Troubleshooting the automatic transmission is simplified by using the proven method of diagnosis. One of the most important things to remember is that there is a definite procedure to follow. Do not take short cuts or assume that critical checks or adjustments have already been made.

The following procedures are recommended for checking and/or verifying that the various components are adjusted and operating properly. Use Rotunda Automatic Transmission Tester 014-00737 or equivalent. Follow the manufacturer's instructions.

Transmission Fluid Cooler Flow Check

The linkage, fluid and control pressure must be within specifications before performing this flow check.

Remove the transmission dipstick from the filler tube. Place a funnel in the transmission filler tube. Raise the vehicle and remove the cooler return line from its fitting in the case. Attach a hose to the cooler return line and fasten the free end of the hose in the funnel installed in the filler tube.

Start the engine and set idle speed at 1000 rpm with the transmission in NEUTRAL.

Observe the fluid flow at the funnel. When the flow is solid (air bleeding has been completed), the flow should be liberal. If there is not a liberal flow at 1000 rpm in NEUTRAL, low pump capacity, main circuit system leakage, or cooler system restriction is indicated.

Check both of the metal cooler lines between the transmission and radiator for restrictions. Check for restrictions in the metal or rubber cooler lines to and from the auxiliary cooler, if so equipped. Visually check and physically feel all bends for kinks, especially rubber cooler lines, that would restrict flow and could result in transmission overheating or lack of lubrication.

To separate transmission trouble from cooler system trouble, observe the flow at the transmission case converter-out fitting.