HARSH SHIFT CONDITION (ON CAR SERVICE INFORMATION)

SUBJECT: HARSH SHIFT CONDITIONS AND ON CAR SERVICE INFORMATION FOR HARSH 3-2 DOWNSHIFTS

MODEL/YEARS: 1985-92 VEHICLES WITH HYDRA-MATIC 4T60 TRANSAXLES (RPO-ME9)

This bulletin covers harsh 3-2 shift conditions and specific service information which applies to the correction of these conditions. This bulletin also cancels and replaces Dealer Technical Bulletin 90-T-55, which may be discarded.

IMPORTANT: Before performing any service, verify the customer's concern is a 3-2 downshift and not a 2-1 downshift concern. A TECH 1 or other scan tool can be used as an aid to make this determination. Also, it would be an aid for diagnosis to put the transaxle in manual 3rd, or 2nd before and after the concern to determine actual gears of the shift complaint.

Notice: DO NOT USE General Motors limited slip differential lubricant additive or equivalent to eliminate undesirable "shift-feel", or to reduce harsh shifting, or to minimize torque converter apply/release "shudder." This will prematurely distress the clutches and bands in the transaxle/transmission by elongating shift-engagement times and increasing slippage between surfaces, even though it might provide better shift-feel for the customer at first. Also, the static capacity (a measure of load-holding capacity) will be reduced by at least 50 percent (i.e., the transaxle/transmission will only handle one half the Combined Gross Vehicle Weight as it did before without slipping). The customer may be pleased at first, but will be back to the dealership with a distressed transaxle/transmission.

Before resorting to the 3-2 Service Packages available, verify that the harsh condition is not caused by the following:

o Vacuum Leaks (low vacuum supply to the vacuum modulator) Remember, the available vacuum will be less at higher altitudes. Also, a restricted exhaust (plugged catalytic converter) can cause a low vacuum. Measure exhaust system pressure as outlined in Section 6F of the Service Manual.

o Faulty Vacuum Modulator (19) Check for proper modulator function as outlined in Section 7 (Transaxle Unit Repair) of your Service Manual. Also verify the modulator valve (17) moves freely in its bore and is free of nicks or burrs.

o Sticking 1-2 Servo Control Valve (373) in Control Valve Assembly (35)

o Sticking 3-2 Control Valve (340) in Control Valve Assembly (35)

o Missing or Mislocated Checkballs (2, 4,12) (refer to Figure 1)

o Sticking 3-2 Coast down Valve (218) in Oil Pump Assembly (44)

o Improper TN Cable Adjustment (refer to Section 7A of your Service Manual for the proper TN cable adjustment procedure)

IMPORTANT: Service replacement Transaxle Assemblies (SRTA) are built with original calibrations and may need to be updated with a service 3-2 control valve spring per customer requirements.

Refer to the HYDRA-MATIC 4T60 (ME 9) Automatic Transaxle Unit Repair Table of Contents for appropriate service information.

VERY HARSH PART THROTTLE 3-2 SHIFT AT 20-40 MPH:

1985 - 1990 Cutlass Ciera/Cruiser, Cutlass Supreme, Eighty Eight, Ninety Eight, And Toronado/Trofeo

A part throttle downshift is a quick apply of the accelerator pedal beyond a medium throttle position (approximately 1/2 of accelerator pedal travel), forcing a downshift.

A harsh part throttle 3-2 shift at 20-40 mph may be caused by a missing or mislocated #2 3-2 control checkball (Figure 1). Remove the valve body to inspect for proper checkball location or damage to the spacer plate. A mislocated checkball may have bent the spacer plate. Also inspect the #12 1-2 servo feed checkball to ensure it is seating properly.

HARSH 3-2 AND/OR 4-2 SHIFTS: --------------------------- Cutlass Ciera/Cruiser, Cutlass Supreme, Eighty Eight, Ninety Eight, And Toronado/Trofeo Harsh 3-2 and 4-2 shifts at any altitude may be caused by a missing or partial hole in the spacer plate. Remove the valve body and inspect the spacer plate for a missing or partial governor passage hole (25) as shown in Figure 2. A partial hole can be drilled out using a #77 drill bit to meet the hole size requirement of .46 mm (.018'). If the hole is missing, use the spacer plate gasket and control valve body as a guide to locate and drill the hole, or replace the spacer plate.

INTERMITTENT HARSH PART THROTTLE 3.2 SHIFT: ------------------------------------------ 1985-1/2 - All Models Except With 2.8L Or 3.0L Engines

1986 - All Models Except 2.8L Or 3.0L Engines With Transaxles Built Prior To July 21, 1986 (Julian Date 202)

An intermittent harsh 3-2 shift may be caused by a broken 3-2 line control retainer (435) (refer to Figure 3). Remove the transaxle side cover to access the 3-2 line control valve and, if necessary, replace a broken retainer with P/N 8658678. Also ensure the 3-2 line control valve moves freely in its bore.

HARSH 3-2 SHIFT **HIGH ALTITUDE ONLY**: -------------------------------------- 1985-1990 Cutlass Ciera/Cruiser, Cutless Supreme, Eighty Eight, Ninety Eight, And Toronado/Trofeo

1991 Cutlass Ciera/Cruiser, Cutlass Supreme, Eighty Eight

1992 Cutlass Ciera/Cruiser, Cutlass Supreme

Note: This information applies to the vehicles mentioned above that are operated in counties which have substantially all of their area above 4000 ft. (Ref. Federal Register). For your convenience we have listed the Designated High Altitude Counties below.

Arizona

Apache Cochise Coconino Navajo Yavapai

Colorado

Adams Elbert Mesa Summit Alamosa El Paso Mineral Teller Arapahoe Fremont Moffat Washington Archuleta Garfield Montezuma Weld Boulder Gilpin Montrose Chaffee Grand Morgan Cheyenne Gunnison Otero Clear Creek Hinsdale Ouray Conejos Huerfano Park Costilla Jackson Pitkin Crowley Jefferson Pueblo Custer Kit Carson Rio Bianco Dolores Lake Rio Grande Delta La Planta Routt Denver Larimer Sanguache Douglas Las Animas San Juan Eagle Lincoln San Miguel

Idaho

Bannock Custer Bow Lake Franlkin Bingham Fremont Blaine Jefferson Bonneville Lemhi Butte Madison Camas Minidoka Caribou Oneida Cassia Power Clark Teton Valley

Montana

Beaverhead Deer Lodge Gallatin Jefferson Judith Basin Madison Meagher Park Powell Silver Bow Wheatland

Nevada

Carson City Nye Douglas Pershing Elko Storey Esmeralda Washoe Eureka White Pine Humbolt Lander Lincoln Lyon Mineral

Nebraska

Banner Cheyenne Kimball Sioux

New Mexico

Bemalillo Los Alamos Santa Fe Catron Luna Sierra Colfax McKinley Socorro Curry Mora Taos De Baca Otero Torrance Grant Rio Arriba Union Gaudalupe Roosevelt Valencia Harding Sandoval Hidalgo San Juan Lincoln San Miguel

Oregon

Harney Klamath Lake

Texas

Hudspeth Jeff Davis Parmer

Utah

Beaver Morgan Box Elder Plute Cache Rich Carbon Salt Lam Daggett San Juan Davis Sanpete Duchesne Sevier Emery Summitt Garfield Tooele Grand Uintah Iron Utah Juab Wasatch Kane Wayne Milard Weber

Wyoming

Albany Natrona Campbell Niobrara Carbon Park Converse Platte Freemont Sublette Goshen Sweetwater Hot Springs Teton Johnson Uinta Laramie Washakie Lincoln Weston

A harsh 3-2shift condition at high altitude may be corrected by installing the appropriate Service Package containing:

o 1 3-2 Control Valve Spring (341) (refer to Figure 4)

o 2 Spacer Plate Gaskets

o 3 Instruction Sheets

3-2 Control Valve Spring Transaxle Model Identification Package (See the service manual Number for model identification) ------------ ------------------------------ 8646979 2WWH 8646980 2YBH, 2YCH, 2YKH 8646982 2WFH

8646979 1WWH, 1WSH, 1WXH, 1PAH 8646982 1YDH, 1CHH, 1YHH, 1CJM, 1YSH 1CAH, 1YTH, 1CBH, 1YTH, 1CBH 8646981 1WMH, 1BHH 8646982 1WJH, 1BJH, 1WPH, 1BWH, 1WFH, IBDH, 1WDH, IBAH

8646979 0PAH, 0WXH 8646980 0AAH, 0ABH, 0AFH, 0ANH, 0ATH, 0BFH, 0KCH, 0KDH, 0KPH, 0KRH, 0KLH, 0WHH 8646981 0BHH, 0WMH 8646982 0BAH, 0BDH, 0BWH, 0BJH, 0CJH 0CHH, 0WDH, 0WFH, 0WPH, 0WJH 8646993 0LMH, 0LNH, 0YKH, 0YLH, 0YSH, 0YTH, 0YDH, 0YHH 8662932 0AJH, 0BPH, 0KHH, 0WNH

8646953 9AAH, 9ABH, 9AFH, 9ANH, 9ATH, 9AJH 8646980 9BPH, 9WRH 8646981 9BHH, 9PAH, 9WBH, 9WCH 8646982 9BAH, 9BDH, 9BJH, 9BWH, 9YCH, 9YAH, 9YBH, 9YJH, 9YFH 8646993 9BFH, 9BMH, 9WUH, 9VYH

8646994 9CDH, 9CLH, 0CPH, 9CYH, 9CZH 8662932 9PBH, 9WLH, 9WKH 8675936 9ACH, 9ADH, 9AHH (Use ALL components In package EXCEPT labels)

8646979 8FCH 96469828 8BKH, 8FBH 8646993 8BJH, 8BRH, 8BTH, 8FJH

8646979 7FCH, 7FZH 8646982 7FBH, 7FKH 8646993 7FJH, 7FNH, 7FRH, 7FTH

8646979 6BCH, 6BDH, 6BMH, 6BZH, 6FCH, 6FZH 8646980 6BAH 8646981 6ACH, 6AWH 8646982 6AAH, 6AMH, 6AFH, 6APH, 6ASH, 6AYH, 6BBH, 6BHH, 6FBH 8646983 6CMH, 6CNH, 6CFH 8646992 6BLH, 6BTH, 6BYH 8646993 6FTH, 6FYH

8646979 5BXH 8646981 5ACH, 5AYH, SBWH 8646982 5AMH 8646983 5CMH, 5CNH 8646993 5BRH, 5CPH, 5CWH 8646994 5BVH

Before installing Service Replacement Transaxle Assembly (SRTA) in areas designated as "high altitude," install the new 3-2 control valve spring. Refer to pages 2 and 3 for a geographical listing of high altitude areas.

HARSH 3-2 SHIFT **LOW ALTITUDE* ONLY**: -------------------------------------- 1985-1990 Cutlass Ciera/Cruiser, Cutless Supreme, Eighty Eight, Ninety Eight, And Toronado/Trofeo

1991 Cutlass Ciera/Cruiser, Cutlass Supreme, Eighty Eight

1992 Cutlass Ciera/Cruiser, Cutlass Supreme

Note: Low Altitude areas are those counties not listed on "Designated High Altitude Counties on pages 2 and 3.

A harsh 3-2 shift at low altitude in a 1991 or 1992 model may be corrected by installing the appropriate service package which contains:

o 1 3-2 Control Valve Spring (341) (refer to Figure 4)

o 2 Spacer Plate Gaskets

o 3 Instruction Sheet

3-2 Control Valve Spring Package Number Transaxle Model Identification ------------ ------------------------------ 8646979 2YBH, 2YCH, 2YKH 8646993 2WFH 8662907 2WWH

8646979 1YDH, 1CHH, 1YHH, 1CJH, 1YSH, 1CAH, 1YTH, 1CBH 8646980 1WMH, 1BHH 8646993 1WFH, 1BDH,1WDH, 1BAH, 1WJH, 1BJH 1WPH, 1BWH 8662907 1PAH

8646979 0YKH, 0YLH, 0BFH, 0YDH, 0YHH, 0WHH 8646980 0AAH, 0ABH, 0AFH, 0ANH, 0ATH, 0BHH, 0KCH, 0KDH, 0KPH 0KRH, 0KLH, 0WMH 8646981 0CHH, 0CJH 8646993 0BAH, 0BDH, 0BWH, 0BJH, 0WDH, 0WFH, 0WPH, 0WJH 8662907 0PAH, 0WXH 8662932 0AJH, 0KHH 8675962 0BPH, 0WNH 8675963 0LMH, 0LNH, 0YSH, 0YTH

8646953 9AAH, 9ABH, 9AFH, 9AJH, 9ANH, 9ATH, 9WTH 8646980 9BFH, 9BMH, 9WUH, 9WZH, 9VYH 8646981 9BAH, 9BDH, 9BJH, 9BWH, 9YAH, 9YBH, 9YJH, 9YFH, 9YCH 8646993 9BHH, 9PAH, 9WBH, 9BCH 8662932 9BPH, 9WRH 8675936 9ACH, 9ADH, 9AHH, (Use ALL components in package EXCEPT labels)

8646979 8FJH, 8BJH, 8BTH, 8BYH 8646980 8BRH 8646993 8FBH, 8BKH 8662932 8FCH

8646979 7FJH, 7FNH, 7FRH, 7FTH 8646993 7FBH, 7FKH 8662932 6BHH 8646993 6FBH 8646994 6CNH, 6CMH, 6CFH 8662907 6BCH, 6BDH, 6BMH, 6BZH 8662932 6FCH, 6FZH

HARSH 3-2 SHIFT MANEUVER AT 17-20 MPH:

1985-1/2 - 1986 Cutlass Ciera/Cruiser, Cutlass Supreme, Eighty Eight, Ninety Eight, And Tornado/Trofeo A 3-2 shift maneuver is obtained by allowing the vehicle to coast down to 17-20 mph (with closed or zero throttle) and then stepping into the throttle to obtain a 3-2 shift.

At start of production (SOP) 1987, an orifice pipe was added between the 1-2 servo release cover plate and the 3-2 coast down valve to allow a smoother second gear apply (Figure 5). The four new parts installed as a set will service certain past model transaxles with a harsh 3-2 shift maneuver condition.

P/N 8646995 Package Contents: Transaxle Model Identifcation ---------------------------- ----------------------------- 1 Oil Pump Body Assembly Complete 6AAH, 6ACH, 6ADH, 1 Release Cover Gasket SAFH, 6AMH, 6ANH 1 Plug & Release Cover Pipe Assembly 6APH, 6ARH, 6ASH 1 Conduit Clip 6ATH, 6AWH, 6AYH, 5AM, 5AF

P/N 8646996 Package Contents: ---------------------------- 1 Oil Pump Body Assembly Complete 6BAH, 6BBH, 6BCH, 1 Release Cover Gasket 6BDH, 6BHH, 6BLH 1 Plug & Release Cover Pips Assembly 6BMH, 6BSH, 6BTH 1 Conduit Clip 6BYH, 6BZH, 6CFH, 6CMH, 6CNH, 6HBH, 6HJH 5BR, 5BV, 5BW, 5CM 5CN, 5HJ, 5HA

If the new pump body assembly has a "one terminal" 3rd clutch switch, remove it and replace with the "two terminal" 3rd clutch switch from the original pump body assembly.

When servicing a transaxle for the above described condition in designated high altitude areas, also install the 3-2 control valve spring package described in Section 11 of this bulletin.

Also ensure the 3-2 control valve and 1-2 servo control valve move freely in their bores.

HARSH 3-2 COASTDOWN BUMP 3.8L OR 4.5L AT 15-22 MPH: -------------------------------------------------- 1985-87 Cutlass Clara/Cruiser, Eighty Eight, Ninety Eight, And Toronado/Trofeo, With Transaxles Built Prior To December 18, 1986 (Julian Date 352) And 3.SL Engings

A coastdown bump is obtained by allowing the vehicle to coastdown to 15-22 mph (with closed or zero throttle) and a sudden and forceful apply of the 1-2 band is felt when the transaxle shifts from third to second gear.

A harsh 3-2 coastdown bump may be caused by the 1-2 servo cushion spring. This condition may be corrected by replacing the 1-2 servo cushion spring with P/N 8668123. Refer to the chart below to determine the transaxle model and Julian Date when the new springs were first used in production units.

Transaxle Build Date/ Transaxle Build Date/ Model Julian Date Model Julian Date --------- ----------- --------- ----------- 7FBH 12-11-86/3451 7FSH 12-1-86/3451 7FCH 12-11-86/345 7FTH 12-11-86/345 7FJH 12-15-86/349 7FZH 12-12-86/346 7FKH 12-11-86/345 7HAH 12-15-86/349 7FNH 12-11-86/345 7HCH 12-18-86/352 7FRH 12-17-86/351

If the above condition persists make sure the 3-2 coastdown valve (located in the oil pump body) is not stuck and moves freely in its bore.

HARSH UPSHIFTS - HIGH ALTITUDE ONLY:

1985-86 Cutlass Ciera/Cruiser With 2.BL Engine

Harsh upshifts for ALL GEARS at high altitudes may be caused by high line pressure due to low engine vacuum. This condition may be corrected on certain transaxle models by installing the appropriate aneroid modulator Service Package.

P/N 8646956 Transaxle Model Identification Package Contents ------------------------------ ---------------- 1 Vacuum Modulator Valve 6CFH, 6CMH, 6HBH, 6HJH, 5CM,, 5CN, SCP, 5CW, 5HA, 5HJ, 5HT 1 Modulator Valve 1 O-Ring Seal 1 Instruction Sheet

A new vacuum line from the engine to the vacuum modulator, P/N 14062624, MUST also be installed when using the service packages listed above.

All parts listed in this bulletin are currently available from GMSPO.

Other items affecting harsh upshift conditions are:

o Engine vacuum leaks

o Sticking modulator valve

o Restrictions in the vacuum lines such as paint in the modulator tube and/or carbon at the throttle body fitting

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.