2006 GMC Sierra 1500 Pickup Owner's Manual - Page 442

How to Add Automatic Transmission Fluid Refer to the Maintenance Schedule to determine what kind of transmission fluid to use. See Recommended Fluids and Lubricants (Gasoline Engine) on page 6-14. Add fluid only after checking the transmission fluid while it is hot. A cold check is used only as a reference. If the fluid level is low, add only enough of the proper fluid to bring the level up to the HOT area for a hot check. It does not take much fluid, generally less than one pint (0.5 L). Do not overfill. Notice: Use of the incorrect automatic transmission fluid may damage your vehicle, and the damages may not be covered by your warranty. Always use the automatic transmission fluid listed in Recommended Fluids and Lubricants (Gasoline Engine) on page 6-14. Automatic Transmission Fluid (Allison Transmission®) When to Check and Change Automatic Transmission Fluid A good time to check your automatic transmission fluid level is when the engine oil is changed. Change the fluid and filter at the intervals listed in Additional Required Services (Gasoline Engine) on page 6-7, and be sure to use the transmission fluid listed in Recommended Fluids and Lubricants (Gasoline Engine) on page 6-14. How to Check Automatic Transmission Fluid Because this operation can be a little difficult, you may choose to have this done at the dealership service department. If you do it yourself, be sure to follow all the instructions here, or you could get a false reading on the dipstick. • After adding fluid, recheck the fluid level as • described under "How to Check Automatic Transmission Fluid," earlier in this section. When the correct fluid level is obtained, push the dipstick back in all the way; then flip the handle down to lock the dipstick in place. 5-30