EARLY SHIFT POINTS SPECS AND DIAGNOSIS EXPLAINED

MODELS AFFECTED: 1988 SKYLARKS WITH THE LD2 2.3L QUAD 4 ENGINE (VIN CODE D)

Comments have been received that the 1-2 and 2-3 upshifts happen 'early' or at too low a vehicle speed on 1988 Skylarks equipped with Quad 4 (LD2) engines and 125C (MD9) transaxles. A Shift Speed Chart is printed on page 7A-3 of the 1988 New Product Information Manual for Skyhawk/Skylark.

The 125C model KDC with a 2.84 final drive ratio is used with the Quad 4 engine. It is calibrated for minimum throttle shift points as follows:

Ist to 2nd upshift................... 9-12 mph 2nd to 3rd upshift................... 17-19 mph 3rd to 2nd coastdown................. 15-17 mph 2nd to lst coastdown................. 6-10 mph Minimum TCC apply.................... 34 mph

Minimum throttle shifts are accomplished by accelerating the car from a stop with just enough throttle opening to make the car gain speed. As throttle opening is increased, the shift points will happen at a higher speed. These speeds may vary slightly from car to car with different engine loads.

Vehicles with shift speeds falling within the above ranges should be considered calibrated correctly and no T.V. cable adjustment should be made to move the shift points to higher speeds.

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.