How To Add Fluid - GMC 2003 C4C042 Owner's Manual

How to Check and What to Use
Check the fluid level only when your engine is off, the
vehicle is parked on a level place and the transmission is
cool enough for you to rest your fingers on the
transmission case.
Then, follow these steps:
1. Remove the filler plug.
2. Check to be sure that the lubricant level is up
to the bottom of the fill opening. On heavy duty
transmissions (an inch of oil level equals about
one gallon of fluid.)
3. If the fluid level is good, install the plug and be sure
it is fully seated. If the fluid level is low, add more
fluid as described in the next steps.

How to Add Fluid

Here's how to add fluid. Refer to the Maintenance
Schedule to determine the proper fluid to use. See
"Recommended Fluids and Lubricants" in the Index.
1. Remove the filler plug.
2. Add fluid at the filler plug hole. Add only enough
fluid to bring the fluid level up to the bottom of the
fill opening.
3. Install the filler plug. Be sure the plug is fully seated.
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