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.

Valve Body and ATF Strainer Removal (A/T)
Remove the ATF feed pipe (A) from the regulator valve body (B).
Remove the ATF feed pipes (C) (D) from the servo body (E).
Remove the ATF strainer (F) (two bolts).
...
Disassembly
Raise and support the vehicle.
Remove the rear wheels.
Release the parking brake, and
remove the brake drum.
Remove the tension pins (A) by pushing respe ...
Camshaft Inspection
Remove the camshaft sprocket.
Remove the rocker arm assembly, then disassemble the rocker arm.
Put the rocker shaft holder bridge on the cylinder head, then tight ...