MANUAL TRANS DIAG./EXCHANGE PROCEDURE (REPLACEMENT)

DIVS INVL 1 5 7

THIS BULLETIN COVERS:

* PRELIMINARY DIAGNOSIS AND EXCHANGE PROCEDURE FOR THE NV4500 MANUAL TRANSMISSION.

* IN ORDER TO PROVIDE NEEDED PRODUCT FEEDBACK, AND UNTIL FURTHER NOTICE ANY NV4500 MANUAL TRANSMISSION REQUIRING WARRANTY REPAIR WILL BE EXCHANGED FOR A REPLACEMENT UNIT.

IMPORTANT: CUSTOMER PAY UNITS REQUIRING REPAIR SHOULD BE SERVICED USING COMPLETE ASSEMBLIES AVAILABLE THROUGH GMSPO.

SERVICE INFORMATION:

* TRANSMISSION IDENTIFICATION INFORMATION:

- THE IDENTIFICATION TAG IS LOCATED ON THE DRIVER'S SIDE PTO COVER AND THE SERIAL NUMBER IS LOCATED ON A BAR CODE LABEL ON TOP OF THE SHIFT COVER (FIGURE 1).

* THIS TRANSMISSION INCORPORATES THE FOLLOWING UNIQUE OPERATING FEATURES WHICH SHOULD NOT BE MISTAKEN FOR A TRANSMISSION PROBLEM.

- LOW AND 1ST GEAR OVERSPEED DOWNSHIFT INHIBITORS. THIS FEATURE PREVENTS OVERSPEED DAMAGE TO DRIVETRAIN COMPONENTS BY MECHANICALLY BLOCKING HIGH RPM 2-1 OR 1-LOW DOWNSHIFTS. ATTEMPTED DOWNSHIFTS INTO 1ST WHEN 2ND GEAR ENGINE SPEEDS ARE ABOVE 3000-3200 RPM OR INTO LOW WHEN 1ST GEAR ENGINE SPEEDS ARE ABOVE 3600-3800 RP WILL BE PREVENTED.

- OVERDRIVE TO REVERSE INHIBITOR. THIS FEATURE PREVENTS SHIFTING THE TRANSMISSION DIRECTLY FROM OVERDRIVE INTO REVERSE. IF AN OVERDRIVE TO REVERSE SHIFT IS DESIRED IT WILL BE NECESSARY TO FIRST MOVE THE SHIFT LEVER TO THE "2-3" POSITION OF NEUTRAL AND THEN INTO REVERSE.

* PRELIMINARY DIAGNOSIS PROCEDURE:

- INSURE CORRECT OIL LEVEL. TRANSMISSION CAPACITY IS 3.78L (4 QTS).

IMPORTANT: THIS TRANSMISSION REQUIRES A SPECIAL SYNTHETIC LUBRICANT P/N 12345871. DO NOT SUBSTITUTE ANY OTHER LUBRICANT AS INTERNAL TRANSMISSION DAMAGE MAY OCCUR.

- INSURE CLUTCH OPERATION IS NORMAL (FIGURE 2).

- INSURE THAT ALL ENGINE AND TRANSMISSION MOUNTS ARE TIGHT.

* ON-VEHICLE WARRANTY SERVICE PROCEDURES (TRANSMISSIONS REMOVAL NOT REQUIRED):

- RESEALING OF THE PTO COVER.

- REPLACEMENT OF THE EXTENSION HOUSING OIL SEAL.

- REPLACEMENT OF THE SPEED SENSOR.

- REPLACEMENT OF THE BACK-UP LAMP SWITCH ASSEMBLY.

* SERVICE MANUAL REFERENCE:

- REFER TO SECTION 7B OF THE 1991 C/K SERVICE MANUAL.

SERVICE ACTION:

* WHILE THIS EXCHANGE PROGRAM IS IN EFFECT, TECHNICAL ASSISTANCE SHOULD BE CONTACTED ANYTIME A PROBLEM IS ENCOUNTERED WITH A NV4500. THE DEALERSHIP WILL THEN BE CONTACTED BY NVG (NEW VENTURE GEAR) TO GATHER FURTHER INFORMATION AND HELP DIAGNOSE THE PROBLEM.

* EXCHANGE TRANSMISSIONS MUST NOT BE DISASSEMBLED AND EXCHANG UNITS MUST BE RETURNED WITH THE STUB LEVER INTACT.

EXCHANGE PROCEDURE:

1. REFERENCE FIGURE 3 AND HAVE INFORMATION AVAILABLE BEFORE CALLING. IT IS NECESSARY TO RECORD THIS INFORMATION AS THE FORM WILL BE RETURNED WITH THE TRANSMISSION. (BLANK FORMS WILL BE SHIPPED WITH EXCHANGE UNIT). RECORD THE THE UNIT SERIAL NUMBER FROM THE BAR CODE LABEL LOCATED ON TOP OF THE SHIFT COVER.

2. CALL GMC TECHNICAL ASSISTANCE (TAC) AT 1-800-624-2022 (CHEVROLET TAN). GMC - TAC (CHEVROLET TAN) WILL SET A CASE, PROVIDE THE DEALERSHIP WITH THE CASE NUMBER AND CONTACT NVG. NVG WILL THEN CONTACT THE DEALERSHIP TO HELP WITH DIAGNOSIS. IF AN EXCHANGE I DETERMINED NECESSARY, THE TRANSMISSION WILL BE SHIPPED TO ARRIVE WITHIN 48 HOURS. REPLACEMENT TRANSMISSION WILL BE SHIPPED FILLE WITH FLUID.

3. WHEN THE EXCHANGE UNIT IS RECEIVED, THE REPLACED UNIT IS TO BE RETURNED TO NVG WITHIN 10 DAYS TO AVOID A CHARGEBACK. THE AUTHORIZATION NUMBER MUST BE WRITTEN ON THE TRANSMISSION CASE IN BLACK MARKER BEFORE ITS RETURN. IF THE CASE IS EXCESSIVELY GREASY, WRITE THE AUTHORIZATION NUMBER ON A TAG AND ATTACH IT TO THE CASE WITH WIRE. A RETURN SHIPPING LABEL WILL BE SENT WITH THE EXCHANGE UNIT.

4. THE REPLACED UNIT MUST BE RETURNED COMPLETE AS REMOVED FROM THE VEHICLE WITHOUT ANY DISASSEMBLY OF THE UNIT. DEALERSHIPS RETURNING UNITS EVEN PARTIALLY DISASSEMBLED WILL BE SUBJECT TO BILLING FOR MATERIALS FURNISHED.

5. THE EXCHANGE UNIT WILL HAVE A PLASTIC BAG ATTACHED TO IT. THIS BAG WILL CONTAIN:

* REPORTING FORM (FIGURE 3) * INSTRUCTION SHEET (FIGURE 4) * RETURN SHIPPING LABEL * RETURN SHIPPING CARRIER INFORMATION

PREPARATION FOR SHIPPING:

1. DRAIN ALL OIL FROM UNIT.

2. REMOVE ALL PLASTIC SHIPPING PLUGS AND COVERS FROM THE REPLACEMENT UNIT AND INSTALL THEM ON THE REPLACED UNIT.

3. PLACE THE REPORT FORM AND A COPY OF THE REPAIR ORDER IN THE ENCLOSED PLASTIC BAG AND ATTACH THE BAG TO THE COMPLAINT UNIT.

4. WRITE THE AUTHORIZATION NUMBER ON THE CASE OF THE COMPLAINT UNIT

5. REPACK THE REPLACED UNIT INTO THE ORIGINAL SHIPPING CONTAINER.

6. PLACE THE SHIPPING LABEL ON THE ORIGINAL SHIPPING CONTAINER.

IMPORTANT: ALL RETURN SHIPPING IS COD TO NVG. SHIPPING INFORMATION IS INCLUDED WITH THE REPLACEMENT UNIT

SERVICE PARTS INFORMATION:

PART NUMBER DESCRIPTION ---------- --------------------------- 12345871 FLUID, MANUAL TRANSMISSION (1 GALLON)

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

FOR REPAIRS PERFORMED UNDER WARRANTY, CLAIMS SHOULD BE SUBMITTED FOR R&R LABOR, AND THE PARTS ALLOWANCE. REPLACEMENT TRANSMISSIONS WILL B SHIPPED TO THE DEALER ON A NO-CHARGE BASIS. TO AVOID A CHARGEBACK, A COPY OF THE CREDIT MEMO PERTAINING TO THE REPLACEMENT, WITH THE OPERATION HIGHLIGHTED, AS WELL AS THE PROOF OF SHIPMENT TO NVG MUST B SENT TO:

WARRANTY PROCESSING DEPT. GMC TRUCK 16 JUDSON ST. PONTIAC, MI 48058

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION MODELS DESCRIPTION TIME --------- ---------- ---------------------- -------- K2720 C2, C3 TRANSMISSION ASSEMBLY, 1.5 HRS. REPLACE

K2720 C3500 HD TRANSMISSION ASSEMBLY, 1.6 HRS REPLACE

K2720 K2, K3 TRANSMISSION ASSEMBLY, 2.5 HRS. REPLACE

PART ALLOWANCE: $150.48 *

* THE AMOUNT IDENTIFIED IN THE "PART ALLOWANCE" ABOVE REPRESENTS 30% OF DEALER NET FOR PARTS THAT WERE FURNISHED BY NVG. THIS AMOUNT IS T BE PLACED IN THE NET ITEM AMOUNT COLUMN OF THE CLAIM AND USE TYPE COD "M".

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.

COPYRIGHT 1991 GMC TRUCK DIVISION, GENERAL MOTORS CORPORATION ALL RIGHTS RESERVED