A/T - Leak at Side Cover Bolt Hole

Bulletin No.: T-93-70
File in Group: 7
Number: 254
Corp.Ref.No.: 277150
Date: March, 1993

SUBJECT:
4T80-E TRANSAXLE LEAK AT SIDE COVER

MODELS AFFECTED:
1993 ELDORADOS, SEVILLES, AND ALLANTES WITH HYDRA-MATIC 4T80-E (RPO MH1)








Some 1993 Eldorados, Sevilles, and Allantes equipped with Hydra-Matic 4T80-E (RPO MH1) transaxles may exhibit a transaxle leak at side cover bolt hole (32). Refer to Figures 1 and 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 through the porous area and past the bolt causing an exterior leak. Refer to Figure 2.

Properly diagnosing a fluid leak can be difficult. To verify where the fluid leak originates use the foot spray and black light procedure which follows:

1. Clean area thoroughly with solvent.

2. Remove the torque converter shield.

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. Identify source and type of leak.

Use a black light to identify the type of oil (transmission fluid is normally red in color but will appear green under black light).

6. If fluid is leaking from the transaxle case cover bolt hole (32), replace the bolt with P/N 11508353. Use GM sealing adhesive, P/N 12346004, or equivalent to seal the porous area and coat the bolt before reassembly. Torque bolt to 20-27 N-m (14-20 lbs.ft.).

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.

7. If the fluid is not leaking at the transaxle case cover bolt, refer to Section 7 in the Service Information Manual for leak inspection points and repair procedures.

8. Road test to warm up the unit to operating temperature (82-93~ C or 180-200~ F) and inspect for leaks with engine running.

9. Turn engine off. Check for leaks caused by drain back.

Parts are currently available from GMSPO.





WARRANTY INFORMATION