TRANSAXLE LEAK AT SIDE COVER (DIAG./INSTALL NEW SIDE COVER)
SUBJECT: 4T80-E TRANSAXLE LEAK AT SIDE COVER (DIAGNOSE/INSTALL NEW SIDE COVER TO CASE COVER BOLT)
VEHICLES AFFECTED: 1993 "E", "K", "V" MODELS
CONDITION: (FIGURE 1)
Some vehicles equipped with 1993 HYDRA-MATIC 4T80-E (RPO MH1) transaxles, may exhibit a transaxle leak at side cover bolt hole (32).
CAUSE: (FIGURE 2)
The transaxle leak may be caused by porosity in the transaxle case cover (33) bolt hole (32). Pressures within the transaxle may force fluid past the porosity and the bolt causing an exterior leak.
CORRECTION:
Properly diagnosing a fluid leak can be difficult. Diagnosis can be simplified by using the Foot Spray and Black Light method. (Perform the following steps to ensure the vehicle has been properly diagnosed and no unnecessary repairs are performed):
Foot Spray & Black Light Procedure
1. Clean area thoroughly with solvent.
2. Remove the torque converter shield (if required).
3. Spray area with pressurized foot spray powder. (Work area must be completely dry before foot powder can be used.)
4. Start engine and idle fast.
5. Repair leak and recheck as necessary. *Use a black light to identify the type of oil (transmission fluid is normally red in colour, but will appear green under black-light). *Leaking oil is generally carried toward the rear of the car by the air stream.
6. Road test to warm up the unit to operating temperature (88 degrees C or 190 degrees F).
7. Inspect for leaks with engine running.
8. Turn engine off, check for leaks caused by drain back.
IMPORTANT: Refer to the 4T80-E Automatic Transaxle Diagnosis Section of the Service Manual (Diagnosis Charts-Fluid Leaks/Foaming) for possible corrections.
IMPORTANT: If the transaxle case cover (33) is removed for any reason, (whether a leak is present or not), Bolt (32) must be discarded and replaced with a new bolt coated with GM Sealing Adhesive (P/N 12346004) or equivalent.
If it is determined that the exterior leak is caused by the above concern, it is necessary to replace bolt (32) with a new production bolt coated with GM Sealing Adhesive or equivalent. The sealing adhesive is used to coat the porosity in the transaxle case cover (33) to prevent an exterior leak.
SERVICE PART INFORMATION:
Current Part Number Description Models
11508353 Bolt, Side Cover All to Case Cover
12346004 GM Sealing Adhesive All (NAES DEALER) (GMCL DEALERS)
For vehicles repaired under warranty use:
Transaxle Oil Leak Analysis and Bolt, fastener and Automatic transmission: Tighten
Labour Time: .7 Hrs.
SERVICE MANUAL PROCEDURE:
Refer to the appropriate 1993 Service Manual for the proper bolt replacement procedures.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
