Refer to the Maintenance Schedule to determine how often to check the lubricant and when to change it. See Scheduled Maintenance .

Refer to the Maintenance Schedule to determine what kind of fluid to use. See Part C: Recommended Fluids and Lubricants .

A good time to have it checked is when the engine oil is checked. See your Maintenance Schedule to find out when to change your transmission fluid.

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.

Here's how to add fluid. Refer to the Maintenance Schedule to determine the proper fluid to use. See Part C: Recommended Fluids and Lubricants .

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.