1999 GMC Sonoma Owner's Manual - Page 257

yellowblue D With your foot on the brake pedal, move the shift lever through each gear range, pausing for about three seconds in each range. Then, position the shift lever in PARK (P). D Let the engine run at idle for three minutes or more. Then, without shutting off the engine, follow these steps: 1. The transmission dipstick is located near the center of the engine compartment. Flip the handle up and then pull out the dipstick and wipe it with a clean rag or paper towel. 3. Check both sides of the dipstick, and read the lower level. The fluid level must be in the COLD area, below the cross-hatched area, for a cold check or in the HOT area or cross-hatched area for a hot check. 4. If the fluid level is in the acceptable range, push the dipstick back in all the way; then flip the handle down to lock the dipstick in place. 2. Push it back in all the way, wait three seconds and then pull it back out again. 6-19