Transmission Fluid Cooler Flow Test

CAUTION: Whenever a transmission has been disassembled to replace worn or damaged parts, the Cooler Bypass Valve (CBV), all transmission fluid coolers (in tank; and auxiliary) and transmission fluid cooler lines must be cleaned and back flushed. Use a torque converter/oil cooler cleaner.

NOTE: Cleaning and backflushing the transmission fluid cooling system along with following all the normal cleaning and inspection procedures during disassembly and reassembly will keep contamination from entering the transmission, causing a repeat repair.

NOTE: The transmission linkage/cable adjustment, fluid level and line pressure must be within specification before performing this test. Refer to Fluid Level Check under Verification of Condition. Refer to Line Pressure Test.

When internal wear or damage has occurred in the transmission, metal particles, clutch plate material, or band material may have been carried into the torque converter and transmission fluid cooler. These contaminants are a major cause of recurring transmission troubles and must be removed from the system be fore the transmission is put back into use.
1. Remove the fluid level indicator from the fluid filler tube.
2. Place a funnel in the fluid filler tube.
3. Raise and support the vehicle.
4. Disconnect the cooler return tube (rear fitting) from the transmission Cooler Bypass Valve (CBV).
5. Connect one end of a hose to the cooler return tube and route the other end of the hose up to a point where it can be inserted into the funnel at the fluid filler tube.
6. Remove the supports and lower the vehicle.
7. Insert the end of a hose into the funnel.
8. Start the engine and run at idle with the transmission in the neutral range.
9. Once a steady flow of fluid (without air bubbles) is observed, remove the hose from the funnel and place the hose in a measuring container for 30 seconds. After 30 seconds place the hose back into the funnel and turn the engine off. Measure the amount of fluid in the container. If adequate flow was observed, approximately 1.0 liter (1.057 quarts) will be in the measuring container; the test is now complete.
10. If adequate flow is not observed, turn off the engine. Disconnect the hose from the cooler return line (transmission inlet).
11. Disconnect the fluid cooler line from the front case fitting and connect the hose to the case fitting (converter out) and repeat Steps 7, 8 and 9.
12. If adequate flow is observed from the transmission then look for a plugged cooler line and/or fluid cooler.
13. If adequate flow is still not observed, repair and/or replacement of the pump and/or converter may be required.