1996 GMC Sonoma Owner's Manual - Page 240

Then, without shutting off the engine, follow these steps: 3. Check both sides of the dipstick, and read the lower level. The fluid level must be in the COLD 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 i n place. 1. Flip the handle up and then pull out the dipstick and wipe it with a clean rag or paper towel. 2. Push it back in all the way, wait three seconds and then pull it back out again. 6-18