Oil Cooler Flow Check

After the new or repaired transmission has been installed, fill to the proper level with DIAMOND ATF SP III or equivalent transmission fluid. The flow should be checked using the following procedure:

CAUTION: With the fluid set at the proper level, transmission fluid collection should not exceed one quart or internal damage to the transmission may occur.

Disconnect the OUTLET line (from cooler) at the transmission and place a collecting container under the disconnected line.

Fig 1: Disconnecting OUTLET Line At Transmission
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Run the engine at curb idle speed with the shift selector in neutral.
If transmission fluid flow is intermittent or it takes more than 20 seconds to collect one quart of transmission fluid, replace the cooler.
If flow is within acceptable limits, reconnect the cooler line. Then fill the transmission to the proper level, using DIAMOND ATF SP III or equivalent transmission fluid.