INTERMITTENT NO UPSHIFT DUE TO ACCELERATOR CABLE
TRANSMISSION APPLICATIONS: SUBJECT: ------------------------- ------- 1988 THM 125C (MD9) INTERMITTENT NO UPSHIFT DUE TO ACCELERATOR CABLE OVERTRAVEL
TRANSMISSION MODELS: VEHICLE APPLICATIONS: ------------------- -------------------- ALL MODELS 1988 N CAR EQUIPPED WITH QUAD 4 (LD2) ENGINE WITHOUT CRUISE CONTROL (K34)
(Revised to Include Labour Operation and Time.)
BULLETIN COVERS:
An intermittent condition of delayed or no upshift may be encountered on 1988 N cars equipped with a Quad 4 (LD 2) engine, THM 125C (MD9) transaxle, and NOT equipped with cruise control (K34).
Vehicles involved: 1988 Cutlass Calais built prior to VIN JM248915 1988 Grand AM built prior to VIN JC704381 1988 Skylark built prior to VIN JMO27919
During vehicle operation, the accelerator control cable pulley/cam assembly may overtravel its closed throttle position if the accelerator pedal "snaps back" when the driver's foot is quickly removed from the pedal or if the pedal is pulled upward from the floor. This can allow the T.V. cable from the transaxle to retract too far into the transaxle allowing the line boost valve to seat which in turn will raise T.V. pressure causing a delayed or no upshift. T. V. pressure can be relieved by shifting into Park or Manual Low or by stopping and restarting the enigne. Upshifts will then be normal but the condition may return with another "snap back" of the accelerator.
Figure 1 shows the cable and pulley/cam assembly used on a vehicle not equipped with cruise control.
To address this condition, install a new accelerator control cable, part number 22542664. The new accelerator cable has a cable stop to eliminate the overtravel. The procedure for installing the cable is listed on page 6C-5 of the 1988 New Product Service Manual or on page 6C-12 of the 1988 Chassis Service Manual.
After installation of the new cable, road test the vehicle to verify proper operation of the accelorator cable and transaxle upshifts.
NOTICE: This condition could occur on a vehicle equipped with cruise control if the cruise control servo cable were to become disconnected or broken.
* Labour Operation Number: T4625 Labour Time: .3 hours.
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.
