A/T - Perform Cooler Flow Test When Replacing A/T
No: TSB-98-23-004DATE: April, 1998
MODEL: See below
SUBJECT:
REPLACEMENT A/T FLOW TEST
PURPOSE
Automatic transmissions requiring replacement may have particles in the ATF trapped in the radiator transmission cooler, causing a plugged or restricted condition. Any vehicle that receives a new (remanufactured) or repaired automatic transmission must have the transmission cooler in the radiator backflushed and a flow test performed.
If the transmission cooler is plugged or restricted, it can cause the replacement transmission to fail. This bulletin contains instructions for flow testing the replacement transmission's cooler.
AFFECTED VEHICLES
All models equipped with automatic transmission
PROCEDURE
Before transmission installation is complete, the A/T radiator cooler and lines must be backflushed. Use Transmission Cooler Flusher (OTC p/n 108-MLR-6906A) or equivalent.
On models equipped with an auxiliary oil cooler, it must be backflushed separately.
After backflushing, verify that the backflush was adequate by performing the following radiator transmission cooler and auxiliary oil cooler flow test:
FLOW TEST (with the new transmission installed)
IMPORTANT:
The transmission must be at normal operating temperature for the flow test.
1. If a graduated container is not available, prepare one as follows:
Using a large clean plastic container, pour in one quart of liquid (such as oil or water). Mark the 1-quart level. Then add another quart and mark the 2-quart level. Discard the liquid, and use the empty marked container for the flow test.
2. To prevent damaging the transmission during the test, overfill the transmission by one quart of ATF.
3. Connect the transmission output line to the cooler inlet nipple. Connect the other cooler hose to the cooler outlet nipple. Place the other end of the hose in the graduated container.
4. With the line from the transmission cooler placed in the container, start the engine in Neutral and watch for clean ATF flow (no bubbles or foam).
Continue until the ATF flows clean and the fluid level reaches the 1-quart mark.
5. When the fluid reaches the 1-quart mark, start the timer for the flow test.
6. Observe the amount of clean ATF output in 20 seconds. Turn off the engine.
a. If less than one quart of fluid is output in 20 seconds, there may be a restriction in the oil cooler(s). Perform Steps 7 through 9.
b. If one quart or more of fluid is output in 20 seconds, go to Step 10.
7. Empty the graduated container. Disconnect the inlet line to the oil cooler and place the line in the empty container.
8. With the inlet line from the oil cooler placed in the container, start the engine in Neutral and watch for clean ATF flow (no bubbles or foam).
Continue until the ATF flows clean and the fluid level reaches the 1-quart mark. Then start the timer for the flow test.
9. Observe the amount of clean ATF output in 20 seconds. Turn off the engine.
a. If less than one quart of fluid is output in 20 seconds, replace the transmission. Then repeat Steps 2 through 6 to verify there is no restriction in the oil cooler(s).
b. If one quart or more of fluid is output in 20 seconds, replace the radiator. Then continue with Step 10.
IMPORTANT:
On models equipped with an auxiliary oil cooler, remove the line to the auxiliary oil cooler from the radiator and repeat Steps 2 through 4 for flow testing.
10. Reconnect the cooler line and fill the transaxle to the proper level. Check fluid level with the transmission in the Neutral position at normal operating temperature. (Checking the ATF level in Park may give an incorrect fluid level reading.) Inspect and repair any leaks as necessary.
WARRANTY INFORMATION
Every automatic transmission replacement or major transmission repair (e.g., torque converter or valve body replacement) must have both a back flush and a flow test performed The flow test must be documented and the test results retained in the vehicle file.
The flow test results must also be recorded in the related warranty claim's "Condition, Cause and Remedy" section.
IMPORTANT:
Warranty claims for A" replacements or major transmission repairs (e.g., torque converter or valve body replacement) where a backflush procedure and a documented flow test were not performed are subject to debit action.