A/T - Cooler Bypass Kit
NO: 21-01-96GROUP: Transmission
DATE: Jan. 26, 1996
SUBJECT: RWD Automatic Transmission Oil Cooler Cold Temperature Bypass Kit
MODELS: 1989 - 1993 (AB) Ram Van/wagon
1989 - 1993 (AN) Dakota
1989 - 1993 (AD) Ram Pickup
1993 (ZJ) Grand Cherokee
SYMPTOM/CONDITION:
At ambient temperatures of -15 degrees F or below, vehicles equipped with a four speed automatic transmission and auxiliary transmission cooler may experience a lack of transmission fluid flow to the transmission. At these low temperatures, the automatic transmission fluid might freeze in the transmission oil cooler lines restricting fluid flow. This can cause damage to the transmission, and in periods of extended driving, transmission failure may result.
DIAGNOSIS:
The cold weather by-pass kit should be installed if any of the following conditions are met:
1. If the vehicle is used in areas of extended cold ambient temperatures (below -15 degrees F).
2. If the transmission has failed in cold ambient temperatures, install the bypass kit when repairing or replacing the transmission. Follow proper cooler flushing and transmission repair/replacement procedures found in the appropriate Service Manual.
NOTE:
In hot ambient temperatures, this kit will decrease the cooling capacity of the transmission's cooling system. As a result, unless the above stated conditions exist, it is not recommended that this kit be installed.
PARTS REQUIRED:
1 4874284 Universal By-Pass Assembly kit (See Figure 1 for kit contents)
REPAIR PROCEDURE:
This bulletin involves the installation of a cold weather by-pass kit to the transmission auxiliary cooler circuit.
1. Disconnect the negative battery cable and isolate.
2. Raise the vehicle for access to the transmission housing. The by-pass assembly will be connected to the existing transmission lines and mounted to the transmission housing by means of a by-pass adapter.
3. During this installation procedure, some transmission fluid will be lost when the transmission cooler lines are cut (allowing by-pass assembly installation). Take proper precautions and check transmission fluid fill level upon completing the installation.
4. If the cold weather by-pass kit has provision for an in-line temperature sensor, the threaded "thermal well" (in the pressure "P" line of the kit) must be plugged with either the temperature sensor from the existing transmission line or the standard pipe plug provided. Consequently, if the vehicle being serviced is equipped with a temperature sensor (i.e., heavy duty BR truck), remove the temperature sensor from the existing line by unthreading and install it in the "pressure" line provided with the kit. Use Mopar Thread Sealant, P/N 4318044, to ensure a leak free seal.
5. Disconnect the pressure and return lines from the transmission housing quick connect fittings.
6. Remove and discard the quick connect fittings from the transmission housing.
7. Apply Mopar Thread Sealant, P/N 4318044, to the threaded by-pass adapter (See Figure 1 to identify the by-pass adapter).
8. Install the threaded by-pass adapter securely into the front pressure port of the transmission housing and torque to 13 ft. lbs.
9. Make sure the snap ring and O-ring are properly installed in their respective grooves on the nose of the by-pass assembly block. Lubricate the O-ring with ATF.
10. Position the by-pass assembly block such that the return port fitting "R" is pointed directly up and the two other fittings are pointed forward.
11. Firmly press the male nose of the by-pass assembly into the female body of the threaded by-pass adapter until it snaps into place. After snapping into place, the by-pass assembly is permanently attached to the adapter.
NOTE:
The bypass assembly can rotate inside the adapter, and removal of the block from the transmission housing (if required) can be accomplished by unthreading the adapter.
CAUTION:
If flushing the by-pass assembly is required, it must be removed from the transmission housing and forward flushed. Failing to remove the valve and reverse flushing will result in transmission failure by plugging the by-pass valves internal drainback valve.
12. Apply Mopar Thread Sealant, P/N 4318044, to the threaded end (transmission housing end) of the compression fitting.
13. Install the threaded compression fitting securely into the rear return port of the transmission housing and torque to 13 ft. lbs.
14. Using a small tubing cutter, cut the existing pressure line at approximately 5" from the transmission housing end. Repeat the procedure for the existing return line.
CAUTION:
After cutting the pressure line, mark it with a piece of tape for identification.
15. Identify the proper "R" tube by using the marked labels attached to the tubes and the diagrams.
16. Connect the return line "R" to the by-pass assembly block and the rearward return port of the transmission housing. Tighten the compression fitting finger tight, and then wrench tighten it an additional 1/2 turn. Tighten the inverted flare nut to 60 in. lbs.
17. Using figures 2, 3, 4, select the appropriate "RR" and "P" tubes for the application.
18. Loosely connect the pressure line "P" to the pressure port fitting "P" on the bypass assembly block.
19. Loosely connect the radiator return line, "RR" to the "RR" port fitting, on the bypass assembly block.
NOTE:
During the installation of the "p" and "rr" lines, the order may be reversed to aid in the assembly process.
20. Make sure that the existing return line is properly re-attached to the hanger bracket and lay the new return line, "RR" beside it
21. Install the hose bracket (12) (required for the overhead line application). Figure 2
NOTE:
When attaching the compression sleeve, refer to figure 2 for proper orientation of the sleeve.
22. Attach clamp (11) and the rubber hose to the "RR" tube and determine the approximate rubber hose routing. For connection to the existing return line, the existing return line may be cut again to provide optimum line routing.
CAUTION:
When routing the tubing and hose be aware of potential moving component interferences, such as the propeller shaft, shift linkage in all positions, TV cable, TV return spring, and TV linkage. Be aware of the exhaust system, all routings should maintain at least one inch of clearance from the exhaust system.
23. Cut the rubber hose so that it has sufficient length to be attached to the existing return line.
24. Loosely connect a nut (7), a compression sleeve (8), and a hose fitting (10) to the existing return line.
25. Using a clamp (11), install the rubber hose onto the hose fitting (10).
26. Evaluate the line routing to ensure moving components and exhaust will not interfere with the new lines.
27. Disconnect the "RR" tube (3) from the By-Pass Block for access to the "P"; port on the block assembly.
NOTE:
When attaching the compression sleeve, refer to figure 2 for proper orientation of the sleeve.
28. Attach a clamp and the rubber hose to the "P" tube and determine the approximate rubber hose routing. For connection to the existing pressure line, the existing pressure line may be cut again to provide optimum line routing.
CAUTION:
When routing the tubing and hose be aware of potential moving component interferences, such as the propeller shaft, shift linkage in all positions, TV cable, TV return spring, and TV linkage. Be aware of the exhaust system, all routings should maintain at least one inch of clearance from the exhaust system.
29. Cut the rubber hose so that it has sufficient length to be attached to the existing pressure line.
30. Loosely connect a nut (7), a compression sleeve (8), and a hose fitting (10) to the existing pressure line.
31. Using a clamp (11), install the rubber hose onto the hose fitting (10).
32. Evaluate the line routing to ensure moving components and exhaust will not interfere with the new lines.
33. Torque both clamps, the compression fitting (finger tight, then wrench tighten 1/2 turn), and the inverted flare nut to 60 in lbs on the "P" line.
34. Connect the "RR" tube and torque both clamps, the compression fitting (finger tight, then wrench tighten 1/2 turn), and the inverted flare nut to 60 in lbs on the "P" line.
35. Re-check to ensure that all connections have been securely tightened.
36. Refer to Figure 2 for view of completed assembly.
37. If applicable, connect the wire harness to the temperature sensor.
38. Lower the vehicle and reconnect the battery cable.
39. Check and adjust the transmission fluid level as outlined in the appropriate Service Manual.
40. Raise the vehicle and check for leaks (idle in Neutral).
CAUTION:
In order to reverse flush the cooling system after any service, it is necessary to remove the by-pass assembly from the transmission housing. Failure to remove the by-pass assembly prior to flushing may result in transmission failure.
POLICY: Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
Labor Operation No: 21-25-17-98 1.2 Hrs.
1989-93 (AB, AD, AN)
1993 (ZJ)
FAILURE CODE: P8 - New Part