TRANSMISSION BULLETIN SUMMARY LISTING. Chevrolet Nova 1985

Model and Year: ALL HYDRAMATIC TRANSMISSIONS

TO: ALL CHEVROLET DEALERS

This Bulletin is to assist the technician in locating and identifying Chevrolet Dealer Service Bulletins released for the study and/or repair of Automatic Transmissions.

The Bulletin Summary Listing is shown by:

Transmission Type Diagnosis Service Infomation and Repair Procedures New Parts Bulletin Number

BULLETIN SUMMARY LISTING TABLE OF CONTENTS

THM 125-C SECTION A DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS 1-A SECTION B SERVICE INFORMATION AND REPAIR PROCEDURES 1-B SECTION C NEW PARTS 1-C

THM 180-C SECTION A DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS 2-A SECTION B 2-B SERVICE INFORMATION AND REPAIR PROCEDURES SECTION C NEW PARTS 2-C

THM 200-C SECTION A DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS 3-A SECTION B SERVICE INFORMATION AND REPAIR PROCEDURES 3-B SECTION C NEW PARTS 3-C

THM 200-4R SECTION A DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS 4-A SECTION B SERVICE INFORMATION AND REPAIR PROCEDURES 4-B SECTION C NEW PARTS 4-C

THM 250-C/350-C SECTION A DIAGNOSED CONDITTONS OR SYMPTOM DESCRIPTIONS 5-A SECTION B SERVICE INFORMATION AND REPAIR PROCEDURES 5-B SECTION C NEW PARTS 5-C

BULLETIN SUMMARY LISTING TABLE OF CONTENTS

THM 400/475 SECTION A DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS 6-A

SECTION B SERVICE INFORMATION AND REPAIR PROCEDURES 6-B

SECTION C NEW PARTS 6-C

THM 440-T4 SECTION A DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS 7-A

SECTION B SERVICE INFORMATION AND REPAIR PROCEDURES 7-B

SECTION C NEW PARTS 7-C

THM 700-R4 SECTION A DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS 8-A

SECTION B SERVICE INFORMATION AND REPAIR PROCEDURES 8-B

SECTION C NEW PARTS 8-C

BULLETIN SUMMARY LISTING

THM 125-C

SECTION A

THM 125-C DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS

GENERAL DIAGNOSIS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS of SYMPTOM ------ ---------- ----------- ----------------- --------------- LEAKS Diagnosing All models CHEV 83-I-50 Diagnosis procedure ----- transmission given for on car oil leaks leak detection.

Correction 1982 CHEV 82-T-131 Service procedure for oil given for on car foaming service when correcting this condition.

Oil 1982-1983 CHEV 85-T-13 Procedure given for exhausting replacement of the valve body cover from vent attaching bolts.

Front 1982 CHEV 83-T-22 Service procedure for Converter correcting an oil pressure lock-up Seal Oil which forces the Leak converter seal out of its bore.

NOISE Noise in 1982-1983 CHEV 83-T-35 Noise condition may ----- Park & All models damage on drive Neutral and/or driven sprocket roller cage bearings or driven sprocket thrust bearing. Illustration provided.

Bearing 1982-1983 CHEV 83-T-85 Noise condition caused noise in All models by a rough surface on Park or the driven sprocket, Neutral where the driven sprocket roller cage bearing locates. Service procedure given.

PERFOR- Diagnosing 1981 CHEV 82-T-24 Condition could be MANCE no Drive caused by worn or or Harsh missing pressure Sbifts regulator valve retaining pin. Service procedure given

Tntermittent 1983 CHEV 83-T-16 Procedure given for the Second Gear CB, HY removal of the primary Starts models spring from the governor assembly.

Torque 1982-1983 CHEV 83-T-53 Additional information Converter All models on possible causes of Shudder torque converter shudder. Illustrations provided.

No Reverse 1980-1983 CHEV 83-T-16 The low/reverse piston or Neutral All models assembly is being to Reverse produced with a 3rd Delayed design lip seal retainer Engagement and oil displacement insert. Illustration given.

Loss of 1982-1984 CHEV 84-I-93 New brazing process for power in OP model converter blades Drive & prevents movement of Reverse blades and reduction of torque multiplica- tion.

Rough 1982-1984 CEHV 84-94 New forward clutch wave Neutral plate has gone into to Drive production to eliminate Engagement this condition. Part number and serial numbers listed.

Torque 1982-1983 CHEV 84-171 Provides a summary of Converter All models possible causes of Shudder apply shudder and crowd shudder. Illustrations provided.

SECTION B

THM 125-C SERVICE INFORMATION AND REPAIR PROCEDURES

GENERAL MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ------ ---------- ---------------- --------------- BEARINGS 1980-1984 CHEV 84-100 Service procedure provided for & WASHERS All models checking and using a new thrust bearing assembly(final drive sun gear to differen- tial). Part numbers also provided.

CASE 1982 CHEV 82-I-94 Installation procedure given All models for missing cup plugs and one pipe plug which may not have been installed during assembly.

1980-1983 CHEV 83-I-89 Service procedure given for All models inspection of case bushing when replacing final drive assembly.

All models CHEV 84-191 Explanation of all key transmission identifications.

1984 CHEV 84-252 Updated chart provides correct case cover part numbers.

1984 CHEV 84-202 Provides information about 1984 vehicles with 1985 transaxles. Use correct parts list when servicing.

1985 CHEV 85-67 This new oil slot will allow transmission fluid to spray onto the drive link chain to provide additional lubrication.

CLUTCHES 1982 CHEV 82-T-63 Air check procedure is given when diagnosis of a burned & BANDS All models forward clutch housing is necessary.

1980-1984 CHEV 84-100 Service procedure and illustration of new All models larger thrust bearing used in 1984 models.

SECTION B

THM 125-C SERVICE INFORMATION AND REPAIR PROCEDURES

GENERAL MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ------- ---------- ----------------- ---------------- CONTROL 1983 CHEV 83-T-66 Service procedure and package VALVE CA, CB number given for new control valve assembly to correct COMPO- CF models firm 1-2 and 3-2 shift flare.

1983 CHEV 83-I-90 Service procedure, illustra- tions and part charts given for assembly and disassembly of the oil pump rotor and slide.

DRIVE All models CHEV 84-146 New service procedure given CHAIN for checking drive link chain using scribe marks. Illustration provided.

OIL All models CHEV (SN) 54-3 Rear oil seal installation PUMP emphasizing cleaning.

1982 CHEV 82-I-56 Bearing assembly and new oil pump shaft seal replacement procedure given. Part number included.

SHAFT 1986 CHEV 85-128 Provides information on correct tool usage ASSEM- All models when installing seal BLIES rings on turbine shaft. SECTION C ---------- THM 125-C NEW PARTS ------------------- GENERAL ITEMS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ------- ----- ---------- ---------------- --------------- BEARINGS Thrust 1980-1984 CHEV 84-100 Service procedure & Bearing All models provided for checking WASHERS Assembly and using a new thrust bearing assembly (final drive sun gear to differential). Parts numbers also provided.

Hex Head All models CHEV 85-36 Describes and Screws & illustrates reusable hex head screw and Conical conical washer assembly Washers when servicing any transmission or transaxle.

CASE Support 1982 CHEV 82-I-35 Installation procedure Fixture of new fixture and Fastener fastener kit. Illustra- Kit tion and part number given.

Trans- 1984 CHEV 84-34 Changes in the 1984 mission transmission case are Case listed.

Case 1984 CHEV 84-254 Updated chart provides Cover correct case cover part numbers.

Case 1984-1985 CHEV 85-67 Provides information Cover All models about new 'V' shaped groove cut in 'drive feed' oil circuit of case cover. Illustra- tion provided.

CLUTCHES Lo and 1982 CHEV 82-T-33 Illustration of 1982 AND Reverse new design lo and BANDS Clutch reverse clutch Assembly assembly. CLUTCHES Intermediate AND Band and 1982 CHEV 82-I-40 Part number and BANDS Direct illustration given Clutch for new wider inter- Assembly mediate band.

Intermediate 1982 CHEV 82-I-88 Contains parts informa- Band and All models tion and number for new Direct service package for the Clutch band and clutch Assembly assemblies that were previously packaged separately.

Auxiliary 1982-1983 CHEV 83-T-41 Service package Valve All models description and part number given for Body Cover this new cover.

Intermediate 1983 CHEV 83-114 New servo cushion Servo spring to eliminate 3-2 coastdown clunk Cushion condition. Service Spring procedure included.

Forward 1985 CHEV 85-64 Bulletin contains & Direct All models service package Clutch description and part numbers.

CONTROL Solenoid 1982 CHEV 82-I-75 New design solenoid and VALE & clip clip assembly includes ASSEMBLY Assembly plastic clip to prevent wires from moving during assembly. Part number chart & illustration given.

Revised 1982 CHEV 82-I-120 Two charts are listed Valve to determine proper Control gasket usage if Space Plate replacement is & Gasket necessary. Service Package CONTROL Auxiliary 1983 CHEV 83-T-41 Illustration showing VALVE Valve changes in the ASSEMBLY Body Cover auxiliary valve body cover. Part number given.

Auxiliary 1980 CHEV 81-1-105 New auxiliary control Control PZ & CV valve assembly for Valve models non-converter clutch Assembly 1981 applications. Service PZ,CV,CP, package numbers CT,CD & CG provided. models

Auxiliary 1983 CHEV 3-132 Service procedure Valve Body given for installa- tion of this new & Auxiliary material valve body Valve Body and gasket to correct Gasket no TCC release or no TCC apply. Chart and illustra- tions.

OIL Oil Pan & Starting CHEV 4-8 These new oil pan PAN Valve Body 1983 and valve body covers are thicker and Cover have a raised rib to prevent leaks.

OIL Oil Weir 1982 CHEV 2-I-44 This new introduced PUMP part will revise the lubrication flow around the differential assembly.

Rear Oil All models CHEV (SN) 54-3 Rear oil seal installa- Seal tion emphasizing cleaning. OIL PUMP Oil Pump Late 1984 CHEV 85-9 Service information Drive shaft and description of & spacer these new parts are assembly, given. Illustration pump shaft and chart included. bearing & seal assembly

TORQUE Torque 1982-1984 CHEV 84-I-93 New brazing process for CON- Converter OP model converter blades VERTER prevents movement of COETO- blades and reduction of NENTS torque multiplication. Potential loss of power in drive and reverse.

Torque All models CHEV (SN) 57-3 Use of end play Converter All years measurement tool on End Play all torque converters. Measurement Chart and illustra- Tool tions.

BULLETIN SUMMARY LISTING

THM 180-C

SECTION A

THM 180-C DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS

GENERAL DIAGNOSIS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS or SYMPTOM ------ ---------- ---------- ----------------- ---------------

SHIFTING Delayed 1982-1983 CHEV 83-T-71 Gives service procedure engagement for servicing governor in first gear seal rings seized in their grooves.

SECTION B

THM 180-C SERVICE INFORMATION AND REPAIR PROCEDURES

GENERAL MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ------ ----------- ---------------- -------------- CASE 1982 CHEV 82-I-41 Please use updated diagram illustrating front case oil passages for future reference.

All models CHEV 84-191 Explanation of all key transmission identifications.

NOISE All models CHEV 84-210 Lists procedure for finding causes of whining noise and slow or slipping engagement.

OIL All models CHEV (SN) 54-3 Rear oil seal installation Pump emphasizing cleaning.

SECTION C

THM 180-C NEW PARTS

GENERAL ITEMS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ------ ----- ---------- ---------------- --------------- BEARINGS Hex Head All models CHEV 85-36 Describes and AND Screws and illustrates reusable WASHERS Conical hex head screw and conical washer assembly Washers when servicing any transmission or transaxle.

OIL Rear Oil All models CHEV (SN)54-3 Rear oil seal installa- PUMP Seal tion emphasizing cleaning.

Wear 1982-1983 CHEV 83-T-30 New oil pump wear plate Plate has been designed to eliminate whining noise. Includes part number.

TORQUE End Play All models CHEV (SN) 57-3 Use of new end play CON- Tool All years measurement tool on all VERTER torque converters is given. Chart and illustrations are included.

BULLETIN SUMMARY LISTING

THM 200-C

SECTION A

THM 200-C DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS

GENERAL DIAGNOSIS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS or SYMPTOM ------ ---------- ---------- ---------------- --------------- LEAKS Transmission 1982 CHEV 82-T-97 This revised pump and oil exhaust- All models case gasket will help ing from eliminate this condi- vent tion. Service informa- tion and illustration given.

Diagnosing All models CHEV 83-I-50 Diagnosis and repair transmission procedure given for use oil leaks when transmission oil leak is detected.

Transmission 1982 CHEV 83-T-9 Service and repair oil exhaust- All models information given for ing from pump to case bolts vent that are too long.

NOISE Whine noise 1983 CHEV 83-T-65 Noise cause could be in First, All models front internal gear Second & noticeable when car is in drive. Part number Reverse given.

PERFOR- Loss of 1982 CHEV 82-T-133 Repair and service MANCE drive and/ CX,CY,CZ,OR procedure given for or no reverse C7,CN,C0,CK broken or cracked oil CB,CW,C9,HB driven pump gear. HF,HH,FL,PS Replacement part numbers also given.

Loss of 1982-1984 CHEV 84-93 New brazing process Power in OR model for converter blades Drive & 1981 prevents movement of Reverse AS,HT,OT blades and reduction 1983-1984 of torque multiplica- OU model tion. SHIFTING 3-2 and/or 1982-1983 CHEV 83-T-23 Repair and service 2-1 coast- CN,HH procedure given. down clunk models Also 2 new assemblies going into production.

Second or 1983 CHEV 83-T-73 Gives service Third gear HO,CS procedure for removal starts models of burrs sticking in the T.V. bushing causing this condition.

Late En- Early 1984 CHEV 84-12 Possible causes for gagement or this condition are Slipping in given with service Reverse procedures and charts.

2-1 Coast- 1984-early CHEV 85-39 Repair procedure given down Clunk 1985 removal of the Primary from the govenor.

Occasional Some 1984- CHEV 85-29 This condition caused long 1-2 early 1985 by exhaust orifice hole shift when which must be drilled cold to 9/64 diameter.

SECTION B

THM 200-C SERVICE INFORMATION AND REPAIR PROCEDURES

GENERAL MODEL/YEAR BULLETIN NUMBER SUBJECT SUMMARY GROUPS ------ ----------- --------------- --------------- CASE All models CHEV 84-191 Explanation of all key transmis- sion identifications.

OIL All models CHEV (SN) 54-3 Rear oil seal installation PUMP emphasizing cleaning.

SECTION C

THM 200-C NEW PARTS

GENERAL ITEMS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ------ ----- ---------- ---------------- --------------- BEARINGS Selective 1982-1983 CHEV 83-I-91 Illustration of new AND Washer All models design for selective WASHERS washer has new identification tab attached to it.

Selective 1982-1983 CHEV 83-I-91 Date of implementation Washer given.

Hex Head All models CHEV 85-36 Describes and illust- Screws & rates reusable hex Conical head screw and conical washer assembly when Washers servicing any transmis- sion or transaxle.

CLUTCHES Servo 1984 CHEV 85-78 Design changes in the AND Cover new style servo cover BANDS Retainer retaining ring are Ring listed along with required part numbers.

CONTROL Control 1982 CHEV 82-152 Beginning 1984 all THM VALVE Valve 200-C were being ASSEMBLY Spacer produced with a new control valve spacer plate with an orificed exhaust to correct coastdown clunk condi- tion.

OIL Rear All models CHEV(SN) 54-3 Rear oil seal instal- PUMP Oil lation emphasizing Seal cleaning.

Pump Body 1982-1983 CHEV 83-I-59 New pump body has Assembly C7,CN,C0,CK the pressure relief CB,CW,HB,HF port from the body HH,HL,PS,C9 casting. CS,H0,JJ

OIL PAN New Oil Pan, Prior to CHEV 83-117 Release of new oil Hex Head 1983-All pan, hex head screw, Screw, & models and conical washer Conical assembly. Water Assembly

TORQUE Torque 1982-1984 CHEV 84-93 New brazing process CONVERTER Converter OR model for converter blades COMPO- 1981 prevents movement of NENTS AS,HT,OT blades and reduction 1983-1984 of torque multiplica- OU model tion. Potential loss of power in drive and reverse.

Torque All models CHEV(SN) 57-3 Use of end play Converter All years measurement tool on End Play all torque converters Measure- is given. Chart ment Tool and illustration are included.

TRANS- Trans- 1982-1983 CHEV 83-T-23 Two new transmission MISSION mission CN,HH assemblies went into ASSEM- Assembly production to correct 3-2 coast down clunk. BLIES A new control valve assembly released for service.

BULLETIN SUMMARY LISTING

THM 200-4R

SECTION A

THM 200-4R DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS

GENERAL DIAGNOSIS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS or SYMPTON ------ ----------- ----------- ----------------- --------------- LEAKS Oil leak All models CHEV 83-I-50 Provides diagnostic procedure once leak is detected.

NOISE Whine in 1983 CHEV 83-T-65 Condition caused by first, All models front internal gear second & assembly. Diagnosis reverse procedure included.

PERFOR- No fourth 1982-1983 CHEV 83-T-29 Provides diagnostic MANCE gear All models procedures to find cause of no 4th gear conditions.

Loss of 1982-1984 CHEV 84-83 New brazing process Power in OM model for converter blades Drive & 1984 prevents movement of Reverse OF,OY blades and reduction models of torque multiplica- tion.

SHIFT- 3-4 Shift All 1982 CHEV 82-T-20 Assembly sequence to ING Feel CR model eliminate rough 3-4 shift feel by in- stalling piston.

Harsh 1983-1984 CHEV 84-179 Instructions given to 1-2 All models check second clutch upshift check ball for possible peening of oil apply hole.

SECTION B

THM 200-4R SERVICE INFORMATION AND REPAIR PROCEDURES (Cont'd) -------------------------------------------------------------

GENERAL MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ---------- ---------------- --------------- ------ CASE All models CHEV 84-191 Explanation of all key transmission identifications.

OIL All models CHEV(SN) 54-3 Rear oil seal cleaning and PUMP greasing emphasized when replacement is necessary.

All models CHEV 84-108 New service procedure for new parts to service the oil pump rotor and slide.

1982 CHEV 82-I-45 Revised Color Code for selective thrush washers between oil pump and over- drive clutch housing.

SHAFT 1982 CHEV 82-I-55 Service and repair informa- All models tion given for rebuilding output shafts with snap rings attached.

VALVE 1982 CHEV(SN) 54-4 Procedure given for check BODY All models ball on car installations of control valve body assemblies.

SECTION C

THM 200-4R NEW PARTS

GENERAL ITEMS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ----- ---------- ---------------- --------------- -------

BEARINGS Selective 1982-1983 CHEV 83-I-91 Illustration of new design AND Washer All models for selective washer. A WASHERS new identification tab is attached.

Selective 1982-1983 CHEV 83-I-91 Date of implementation Washer All models added.

Hex Head All models CHEV 85-36 Describes and illustrates Screws & reusable hex head screws Conical and conical washer Washers assembly when servic- ing any transmission or transaxle.

CLUTCHES 3-4 1982 CHEV 82-I-76 Beginning mid-October AND Accumu- all THM 200-4R were built BANDS lator with new design accumula- Piston tor and "O" ring seal. & "O" ring seal

Servo 1985 CHEV 85-78 Design changes in the Cover servo cover retainer Retainer ring are listed along Ring with required part numbers.

CONTROL Interme- 1983 CHEV 83-T-72 This new servo assembly VALVE diate BR model is to reduce erratic ASSEM- Servo shifts. Lists part BLY Assembly numbers.

CONTROL Service 1983-1984 CHEV 84-216 These 2 new service ASSEM- Packages BQ & OM packages went into BLY model production to correct soft or slipping 1-2 shift.

DIFFEREN- Rear internal 1982 CHEV 82-T-71 Provides information for TIAL DRIVEgear & output servicing new assembly. AXLE FINALshaft Part number indicated. DRIVE assembly

MANUAL Parking 1983 CHEV 83-I-104 Previous rod assembly has VALVE Lock All models been changed to a one piece assembly.

OIL Oil pan All models CHEV 84-104 These new parts will PAN Gasket & reduce oil leaks. Service Bolts procedure included.

OIL Rear Oil All models CHEV(SN) 54-3 Rear oil seal cleaning PUMP Seal and greasing emphasized when replacement is necessary.

Pump 1981-1982 CHEV 82-T-130 New design pump assembly Assembly All models will eliminate a buzz condition. Part numbers and service information given.

TORQUE Torque 1982-1984 CHEV 84-83 New brazing process for CONVER- Converter OM model converter blades prevents TER COM- 1984 movement of blades and PONENTS OF,OY reduction of torque models multiplication. Potential loss of power in drive and reverse.

Torque 1985 CHEV 85-76 Illustration of 298mm Converter All torque converter assembly Lugs models used with diesel engines now with three lugs instead of six.

Torque All models CHEV (SN) 57-3 Use of end play measure- Converter All years ment tool on all torque End Play converters. Chart and Measurement illustrations. Tool

BULLETIN SUMMARY LISTING

THM 250-C/350-C ---------------

SECTION A

THM 250-C/350-C DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS ------------------------------------------------------------

GENERAL DIAGNOSIS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS or SYMPTOM ---------- ---------------- --------------- ------ ---------- CLUTCHES Clutch rattle 1984 CHEV 84-238 Noised caused by AND above 50 mph 250C,XD,WK Low and Reverse BANDS and reverse WN,XE,XH & clutch piston clutch XK models plate assembly. 350C, WS Gives package number model needed.

PERFOR- TCC 1983 CHEV 83-T-74 Bulletin provides MANCE Shudder All models information that identifies the solenoid assembly as possible cause of shudder condition. Breakpoint informa- tion is provided.

SECTION B

THM 250-C/350C SERVICE INFORMATION AND REPAIR PROCEDURES -------------------------------------------------------- GENERAL MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ----------- ---------------- --------------- ------ CASE All models CHEV 84-191 Explanation of all key transmission identifications.

OIL All models CHEV (SN) 54-3 Rear oil seal installation PUMP emphazing cleaning.

1982 CHEV (SN) 54-4 Provides procedure for All models checking oil pressure. Chart provided gives ranges of PSI for zero and full throttle.

BULLETIN SUMMARY LISTING

THM 400/475 -----------

SECTION A

THM 400/475 DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTION -------------------------------------------------------

GENERAL DIAGNOSIS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS or SYMPTON ----------- ---------------- --------------- ------ ----------

LEAKS Oil All models CHEV 83-T-9 Service and repair Exhausting information given from Vent to correct problem. May be caused by too long pump to case bolts.

PER- Loss of 1982-1984 CHEV 84-93 New brazing process FORMANCE Power in for converter blades Drive & prevents movement of Reverse blades and reduction of torque multiplica- tion.

No Gears 1984 CHEV 84-136 Service and repair or Slipping information given for in all inspection of snap ring, Ranges seal, and reverse boost bushing. Replacement part numbers also given.

SECTION B

THM 400/475 SERVICE INFORMATION AND REPAIR PROCEDURES -----------------------------------------------------

GENERAL MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ---------- ---------------- --------------- ------

CASE All models CHEV 84-191 Explanation of locating transmission I.D. and explanation of all key transmission identifications.

1984/475 CHEV 85-18 Four new bolts are now replacing EV,FI,FS four of the six studs in the HR models rear case extension.

OIL All models CHEV (SN) 54-3 Rear oil seal installation PUMP emphasizing leaning.

SECTION C

THM 400/475 NEW PARTS ----------------------

GENERAL ITEMS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ----- ---------- ---------------- --------------- ------ BEARINGS Hex Head All models CHEV 85-36 Describes and illustrates AND Screws and reusable hex head screw WASHERS Conical and conical washer Washers assembly when servicing any transmission or transaxle.

CASE Case Exten- 1984/475 CHEV 85-18 Four new bolts are now sion Bolts EV,FI,FS replacing four of the six HR models studs in the rear case extension.

OIL Rear Oil All models CHEV (SN) 54-3 Rear oil seal installation PUMP Seal emphasizing cleaning.

TORQUE Torque 1982-1984 CHEV 84-93 New brazing process for CONVER- Converter converter blades prevents TER movement of blades and COMPO- reduction of torque multi- NENTS plication. Potential loss of power in drive and reverse.

End All models CHEV (SN) 57-3 Use of end play measure- Play All years ment tool on all torque Tool converters is given. Chart and illustration are included.

BULLETIN SUMMARY LISTING

THM 440-T4

SECTION A

THM 440-T4 DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS

GENERAL DIAGNOSIS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS of SYMPTON ---------- ---------------- --------------- ------- ----------

PERFOR- No TCC apply 1984-1985 CHEV 85-34 Illustration of new TCC MANCE No TCC shudder All models accumulator piston pin designed to eliminate these conditions.

SHIFTING Second 1985 CHEV 85-122 May be caused by 1-2 Gear CP,CW shift valve remaining Starts HT models in upshift position. New governor part numbers given to correct this condition.

SECTION B

THM 440-T4 SERVICE INFORMATION AND REPAIR PROCEDURES

GENERAL MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ---------- ---------------- --------------- ------ CASE All models CHEV 84-191 Explanation of all key transmission identifications.

CLUTCHES 1985 CHEV 84-146 This new servo seal spring retainer AND has been added to reduce damage to BANDS the reverse servo seal during assembly.

All models CHEV 85-6 Part chart listed and description of this new torque converter clutch solenoid screen.

DRIVE All models CHEV 84-146 New service procedure for checking CHAIN chain wear using scribe marks on case.

OIL All models CHEV (SN) 54-3 Rear oil seal illustration PUMP emphasizing cleaning.

SERVICE All models CHEV SER-126 SRTA Program is explained and PARTS All years contrasted to the present UNIT repair procedures. REPAIR

SECTION C

THM 440-T4 NEW PARTS

GENERAL ITEMS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ----- ---------- ---------------- --------------- ------ BEARINGS Hex Head All models CHEV 85-36 Describes and AND Screws and illustrates reusable WASHERS Conical hex head screw and Washers conical washer assembly when servic- ing any transmission or transaxle.

GOVERNOR Governor 1985 CHEV 85-122 New governor assembly ASSEMBLY Assembly CP,CW&HT went into production models to correct second gear starts.

OIL Rear Oil All models CHEV (SN) 54-3 Rear oil seal PUMP Seal installation emphasizing cleaning.

TORQUE End Play All models CHEV (SN) 57-3 Use of end play measure- CONVER- Tool All years ment tool on all torque TER converters is given. COMPO- Chart and illustration NENTS are included.

TRANS- Transmission 1985-1985 1/2 CHEV 85-86 New models are being MISSION Assemblies All models built with a redesign- ASSEM- ed control valve BLIES assembly to give 3-2 downshift more responsiveness. Service and repair information listed.

BULLETIN SUMMARY LISTING

THM 700-R4

SECTION A

THM 700-R4 DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS

GENERAL DIAGNOSIS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS of SYMPTON ---------- ---------------- --------------- ------ ---------- COMPONENT No 4th gear All models CHEV 83-T-42 This condition may CONDI- and Burned be caused by a TIONS 2-4 Band blocked 2-4 servo exhaust hole. The Assembly hole could be blocked with R.T.V. silicone sealant and/or some after market gaskets.

TCC 1983 CHEV 83-I-78 Pinched TCC wires Inoperative All models causing this condi- tion. Special washers have been designed to hold them in place.

Transmission All models CHEV 84-10 Possible causes are Overheating listed for these over- heating conditions usually when the cooler cannot cool adequately and the TCC is inoperative.

Burned 1982 CHEV 83-124 Illustration and part 3-4 Clutch 9Y6 model number given for new 1983 spacer plate to 3YH,3Y9 correct this condi- tion.

Burned 1982-1985 CHEV 84-107 Additional informa- 3-4 Clutch All models tion on burned 3-4 and/or clutch and/or high high 2-3 2-3 shifts. Illustra- tion provided.

LEAKS Oil Pump All models CHEV 83-T-59 Illustration of past Seal design and new revised Assembly oil pump which will Leaking allow for more effective oil drainback.

SECTION A

THM 700-R4 DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS (Cont'd) -----------------------------------------------------------------

GENERAL DIAGNOSIS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS or SYMPTOM ---------- ---------------- --------------- ------ ---------- LEAKS Diagnosing All models CHEV 83-1-95 Procedure given for Trananission diagnosing and repair- Oil Leaks ing transmission oil leaks.

Oil Leak 1982-1983 CHEV 83-I-88 Cause for leak on 4 at Transfer All models wheel drive vehicles Case may be caused by "O" ring seal. Part number included.

Transmission 1983-1984 CHEV 84-61 May be caused by Oil Exhausting All models gasket. Service Out Breather package numbers given to correct.

Transmission All models CHEV 84-69 Service package and Oil Pan procedure given for Leaks new design oil pan.

NOISE Grinding 1982-1984 CHEV 84-86 Changes in new reac- noise in All models tion Internal Gear all ranges are listed. Part numbers and illustra- tion given.

PERFOR- No Drive 1982-1983 CHEV 83-T-51 Cracked oil pump rotor MANCE & Reverse All models may be possible cause for this condition. Service procedure to verify broken oil pump rotor.

Slipping All models CHEV 83-T-55 Diagnosis procedure in Reverse provided for this or no condition. Includes Reserve illustrations of reverse input piston.

SECTION A

THM 700-R4 DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS (Cont'd) -----------------------------------------------------------------

GENERAL DIAGNOSIS GROUPS or SYMPTOM MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY ------ ---------- ---------- ---------------- --------------- PERFOR- No 2nd, 4th All models CHEV 83-I-125 Inspection of the MANCE or Reverse reaction Sun Gear Gear Shell is necessary to find broken hub or Operation stripped spline causing symptom. Illustration provided.

Loss of 1982-1984 CHEV 84-I-93 New brazing process for power in converter blades Drive & prevents movement of Reverse blades and reduction of torque multiplication. Part chart and models listed.

Elimination 1984 CHEV 84-144 Elimination of 4-3 of 4-3 YA&YW downshift switch will Downshift models improve 4-3 downshift. Illustration of 4-3 downshift switch wiring diagam.

Shifting Burned All models CHEV 83-T-43 Service and diagnosis 2-4 band procedure for a slipping and/or or no 1-2 shift condi- 3-4 clutch tion.

Harsh 2-1 1982-1983 CHEV 83-126 New control valve feel or assembly and spacer Delayed plate went into Downshifts production to control this condition. Part number included.

Buzzing 1982 CHEV 82-T-146 New service package noise & All models for spacer plates and Delayed gaskets is given if Upshifts replacement is necessary.

SECTION A

THM 700-R4 DIAGNOSED CONDITIONS OR SYMPTOM DESCRIPTIONS (Cont'd) ---------------------------------------------------------------- GENERAL DIAGNOSIS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS or SYMPTOM ---------- ---------------- --------------- ------ ---------- SHIFTING Erratic 1982-1983 CHEV 83-I-126 Some 1982 and 1983 may Shifting All models exhibit erratic shift conditions which adjust- ing the T.V. cable won't correct. Repair procedure given to cor- rect this condition.

Erratic or All models CHEV 84-13 Worn governor gear may no upshifts cause these conditions. Diagnosis chart is given for servicing governor model year.

Firm or 1982-1984 CHEV 85-53 New service package Harsh early for control valve body 1-2 Shifts 1985 has gone into produc- tion to eliminate this condition. Part number included.

SECTION B

THM 700-R4 SERVICE INFORMATION AND REPAIR PROCEDURES (Cont'd) ------------------------------------------------------------- GENERAL MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ---------- ---------------- --------------- ------- BEARINGS All models CHEV 83-I-108 Service information and procedures AND given when checking for transmis WASHERS sion end play. Illustration and part description given.

CASE 1982-1983 CHEV 83-I-77 Instructions given for installing All models the output shaft yoke to prevent oil seal assembly leaks.

All models CHEV 83-1-60 Service procedure for air check- ing input housing assembly.

All models CHEV 84-191 Automatic transmission identifica- tion information.

CLUTCHES All models CHEV 84-9 Parking pawl must be removed when AND servicing the low and reverse BANDS piston. Instructions given.

All models CHEV 83-T-79 Service information for the For- ward Spring Clutch is given. Service package numbers are included.

All models CHEV 84-103 Service information is given when checking for wear of pinion washer.

1982-1984 CHEV 84-177 Service information is given for All models inspection of burned overrun clutch, forward clutch, 3rd clutch and 4th clutch assembly.

1985 CHEV (SN) 57-3 1985 Service Manual correction All models on the Lo and Reverse clutch piston dimensions.Illustration.

SECTION B

THM 700-R4 SERVICE INFORMATION AND REPAIR PROCEDURES (Cont'd) ------------------------------------------------------------- GENERAL MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ---------- ---------------- --------------- ------ CONTROL 1982-1983 CHEV 83-I-80 Delete any reference to the throttle VALVE All models exhaust valve in 1982 thru 1983 ASSEMBLY service manuals.

1982-1983 83-109 Accumulator spring usage chart listed for spring usage and location.

All models CHEV 84-11 Starting 1984 the 700-R4 is being produced with a T.V. exhaust check ball in the control valve assembly.

1982-1985 CHEV 84-107 Procedure given for air check of All models the 3rd and 4th clutch piston. Illustration.

1983-1984 CHEV 84-68 Service procedure given for removal All models and inspection of the control assembly to prevent lock-up in reverse.

OIL All models CHEV (SN) 54-3 Installation instructions emphasized PUMP for cleaning and greasing when replacement is necessary.

All models CHEV 83-T-86 Four procedures are given for checking possible points for lack of lubrication when transmission shows signs of being burned.

All models CHEV 83-T-62 Bulletin suggests inspection of the "O" ring, oil filter body, and filter retaining clip when diagnosing low oil pressure or pump condition noise.

OIL All models CHEV 83-I-124 Illustration of new end play PUMP tools used to check fixture adapters.

All models CHEV 83-96 Oil pressure switch information and their locations are given.

All models CHEV 84-108 Service procedure for the oil pump rotor and slide. Illustration and charts are given showing pump disassembly.

1982-1985 CHEV 85-35 Steps for the removal and illustra- All models tion of the oil seal assembly requiring the use of Loctite TM RC-609 are provided.

Late 1984 CHEV 85-107 Service parts information on All 1985 the new pump assembly is given. Part numbers included.

SERVICE 1982 CHEV 82-T-116 Bulletin contains 6 pages of MANUAL artwork to be inserted into UPDATE 1982 service manual.

SECTION C

THM 700-R4 NEW PARTS

GENERAL ITEMS MODEL/YEAR BULLETIN NUMBERS SUBJECT SUMMARY GROUPS ------ ---------- ---------------- --------------- ------ BEARINGS Rod End All models CHEV 83-I-103 Beginning with serial AND Clip number 3TC152D all WASHERS 700-R4 are being built with a new rod end clip which features a wider cross section and a stiffening rib.

Snap Ring All models CHEV 83-I-85 Beginning 9/1/83 all 700-R4 were built with a revised snap ring for the reaction sun gear and Lo and Reverse spring retainer to case.

Hex Head All models CHEV 85-36 Describes and Screws and illustrates reusable hex Conical head screws and conical Washers washer assembly when servicing any transmis- sion or transaxle.

CLUTCHES Input All models CHEV 83-I-88 This new assembly will AND Housing & have two rows of drain BANDS Shaft holes which will reduce gear clash during Assembly transfer case shifting.

Oil 1983 CHEV 83-I-79 This new oil pressure Pressure All models plug will be used at Plugs the 2nd, 3rd and 4th clutch pressure tap locations. Illustration provided.

2-4 All models CHEV 83-I-115 This new servo cover and Servo seal will eliminate Cover & leaks which may occur at Seal the 2-4 servo cover.

Clutch 1983 CHEV 83-I-67 New turbine shaft will Housing accomodate a 245mm Turbine converter assembly. Shaft Charts given with part numbers.

CLUTCHES Input All models CHEV 84-117 This new input housing AND Housing and shaft assembly has BANDS Shaft a check valve retainer Assembly pressed into the hous ing.

Input 1982-1984 CHEV 84-177 Went into production Housing All models 4/16/84 to correct Shaft burned forward clutch, overrun clutch, and Assembly 3rd and 4th clutch Oil Pump plate assemblies.

Forward 1982-1985 CHEV 85-63 Beginning in 1984 all Clutch All models models will be produc- Plate ed with thicker clutch plates. Replacement Assembly part numbers are also given.

CONTROL Pinched 1983 CHEV 83-I-78 Washer has been in- VALVE TCC All models stalled on valve body ASSEMBLY Solenoid to hold TCC solenoid Wires wires to prevent pinch ing during assembly and testing. Illustra- tion provided.

Assembly 1982-1983 CHEV 84-43 New control valve & Space All models bodies and spacer plates Plate went into production March 25, 1983 to correct manual 2-1 harsh feel.

Accumu- 1982-1983 CHEV 83-109 Accumulaor spring usage lator chart listed for spring Spring usage and location.

New 1982-1985 CHEV 85-71 Additional information Design All models on the new design Control control valve assembly. Valve Body

CONTROL Link Detent All models CHEV 83-129 This change provides a VALVE Lever to new retention of the ASSEMBLY Manual detent lever to manual Valve valve link without the clip. Illustration.

OIL Rear Oil All models CHEV (SN)54-3 Installation instruc- PUMP Seal tions emphasized for cleaning and greasing when replacement is necessary.

Cover 1983-1984 CHEV 84-61 New covers and gaskets Gasket All models went into production to stop oil exhaust from vent.

TORQUE Torque 1982-1984 CHEV 84-I-93 New brazing process CONVERTER Converter for converter blades COMPONENTS prevents movement of blades and reduction of torque multiplica- tion. Potential loss of power in drive and reverse.

Torque 1985 CHEV 85-76 Illustration of 298mm Converter All models torque converter assembly used Lugs with diesel engines now with three lugs instead of six.

End Play All models CHEV (SN) 57-3 Use of end play Tool All years measurement tool on all torque converters is given. Illustration and chart provided.

BEARINGS Hex Head All models CHEV 85-36 Describes and AND Screws & illustrates reusable hex head screw and WASHERS Conical conical washer assembly Washers when servicing any transmission or transaxle.

OIL Rear Oil All models CHEV (SN) 54-3 Rear oil seal instal- PUMP Seal lation emphasizing cleaning.

TORQUE Torque 1985 CHEV 85-76 Illustration of 298mm CONVER- Converter All models torque converter TER Lugs assembly used with COMPO- diesel engines now NENTS with 3 lugs instead of 6.

End All models CHEV (SN) 57-3 Use of new end play Play All years measurement tool on Tool all torque converters is given. Chart included.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.