GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Guide

Automatic Transmission



When adding fluid or refilling the transmission, always use Dexron II® automatic transmission fluid or the latest superceding Dexron® fluid.


See Figure 1

Check the automatic transmission fluid level at least every 7500 miles. The dipstick can be found in the rear of the engine compartment. The fluid level should be checked only when the transmission is hot (normal operating temperature). The transmission is considered hot after about 15-20 miles of highway driving.

Although the transmission should be checked while the fluid is at normal operating temperature, do not check it if it is at the extreme high end of the operating temperature range. Wait at least 30 minutes if you have just be driving the vehicle in ambient temperatures in excess of 90°F (32°C), at highway speeds for a long time, in heavy traffic (especially in hot weather) or have been pulling a trailer.

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Fig. Fig. 1: Automatic transmission dipstick marks; the proper level for a hot transmission is within the shaded area

  1. Park the truck on a level surface with the engine idling, then shift the transmission into Park and firmly set the parking brake.
  3. With your foot on the brake pedal, move the selector through each gear range (pausing for about 3 seconds in each gear), then place it in Park. Allow the engine to run at idle about 3 more minutes.

When moving the selector through each range, DO NOT race the engine.

  1. With the engi