SUPPLEMENTAL DIAGNOSIS 440-T4 ROUGH SHIFT, TCC SHUDDER, ETC.

1984-85 CUTLASS CIERA & 1985 NINETY-EIGHT

Accurate diagnosis is essential to determine if a transaxle can be corrected by procedures which do not require an exchange unit.

An updated 440-T4 diagnosis section is included in the 1985 Firenza, Calais, Cutlass Ciera and Ninety-Eight Chassis Service Manual, Vol. II. Further diagnostic information is as follows:

No Upshift

A. Governor - Cause may be an imprex particle under governor ball. Imprex is an impregnation plastic used to seal cases against porosity.

When the engine is shut off, the particle may float back into the governor feed passage and then lodge again in the governor when engine is restarted. To correct this condition, remove the governor, reinstall the governor cover and operate the engine to flush the oil passages. Clean the governor. To verify that the cleaned governor is operable, seat the balls by holding the governor weights against them. Pour solvent into the governor shaft and inspect for leakage past the balls. If no leakage is noted, reinstall governor.

B. Leakage at governor oil pipe retainer; loose or stripped retainer bolt.

C. Valve body - 1-2 shift valve train may be stuck in valve body. Remove any burrs or raised metal on valves with a flat hone stone. DO NOT remove any more metal from valve than necessary. 1-2 valve is an aluminum alloy. Inspect TV valve for freeness.

The valve body can be removed and replaced without removing the transaxle from the car. Use care to catch check balls during removal.

TCC Shudder

A. A rolled or cut TCC accumu!ator piston seal.

B. Turbine shaft seals cut or damaged.

C. TCC solenoid "O" ring cut or broken. On-car service.

Intermittent No Drive or No Drive At All

Input sprag failure.

Erratic. Rough Shifts. Slipping Shifts. 2nd Gear Starts ------------------------------------------------------- A. Vacuum related conditions. Refer to Dealer Technical Bulletin 85-T-16.

B. A vacuum line that is pinched or kinked may cause vacuum to be retained in the modulator, resulting in low pressure and possible second clutch distress. If fluid inspection indicates a burned clutch, a SRTA unit should be considered. Replace vacuum line.

C. A vacuum problem may result in No.10 check ball peening into the spacer plate seat. Leakage at No. 10 check ball may influence shift quality or TCC operation. On-car correction is recommended if the clutch is not burned.

lst Gear Shudder

A. May also exhibit:

- Slip or second gear start

- Slip or flare on 2-3 shift

- Flare/freewheel in 3rd on light acceleration

- No drive, reverse OK

B. Leak at l-2 servo apply or release pipe to valve body or case seal.

No Forward Gear

A. No forward gear - Slips all ranges. Input clutch maybe burnt.

B. Input accumulator piston cocking in bore. The input accumulator piston is located on the case side of the channel plate.

Shudder on 3-4 Shift

Turbine shaft "O" ring cut or mining.

TCC on at Stops

Engine Stalls - may have a valve body knockout slug lodged in TCC apply valve; TCC apply valve locked in apply position.

Fluid Burned. Slips in Second ----------------------------- Pinched vacuum line holding vacuum in modulator causing low pressure and a burned second clutch. A SRTA unit should be considered. Replace vacuum line.

Harsh 4-3 Downshift

1. Check TCC circuit with a test light to check TCC release before down shift.

NOTICE: Test light bulb must have enough resistance so that it will not ground out terminal F. Bulb no. 73, WDDGM part number 9436790 or bulb no. 756, WDDGM part number 9428049 has adequate resistance.

PROM, part number 16047215 described in Dealer Technical Bulletin 85-T-13 assures TCC release before downshift. This PROM applies ONLY to 1985 Ninety-Eight models with 3.8L engines built PRIOR to the following VINs:

F4328962 F1326511

Later production cars have "WF4" on the Service Part Identification Label which identifies a later ECM circuit which assures TCC release.

2. Incorrect TV cable adjustment - The TV cable controls shift timing only. If misadjusted, upshifts will be incorrectly timed.

3. Incorrect throttle position sensor operation or adjustment.

Refer to pages 6E3-177 and 6E3-178 of the 1985 chassis service manual for adjustment procedure.

4. Number 1 check ball missing.

5. Number 10 check ball sticking or peened into spacer plate.

Harsh 3-2 Downshift

1. 3.8L 1985 model only - Replace 3-2 downshift spring in valve body with new spring available by contacting the Oldsmobile Technical Service Communication System. This correction does NOT apply to models equipped with 3.OL engines or 1985 1/2 models.

2. Missing check ball number 2, 4 or l2.

3. Valve body- Sticking 3-2 control valve, 3-2 coast valve or l-2 servo control valve.

4. Vacuum loss - To diagnose, connect direct manifold vacuum of at least 13 inches to the modulator on 1985 models equipped with an aspirator solenoid.

Whine Noise

A whine or whistle noise under acceleration may be due to:

- Low fluid level

- Filter-to-case seal leak

- Leak at filter crimp

NOTICE: Due to thermo-element operation, fluid level after a refill will require rechecking after warm operation such as a road test to ensure that transaxle is adequately filled.

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.