Follow these instructions to keep the ATF cooler cleaner working properly:
Replace the two magnetic nonbypass spin-on filters after every 20 hours of use, based on the hour meter, or when you notice a restriction in the ATF flow.
Check the level and condition of the fluid in the tank before each use.
Replace the ATF in the tank when it looks dark or dirty.

ATF Replacement (A/T)
NOTE: Keep all foreign particles out of the transmission.
Warm up the engine to normal operating temperature (the radiator fan
comes on), and turn the engine off.
Raise the vehic ...
Engine Block Drain Bolt/Sealing Bolt Installation
NOTE:
When installing the drain bolt (A), always use a new washer.
When installing the sealing bolt(s) (B), always use a new bolt(s) and
washer(s) (C).
...
Intermediate Shaft Removal (A/T)
Drain the transmission fluid. Reinstall the drain plug with a new sealing
washer.
Remove the right driveshaft.
Remove the shift cable cover (A).
Re ...