A/T - 4T80E Slips in 4th Gear/No 4th Gear/DTC P0734 Set

File In Section: 07 - Transmission/Transaxle

Bulletin No.: 01-07-30-005A

Date: May, 2001

TECHNICAL

Subject:
Slipping in Fourth Gear or No Fourth Gear, DTC P0734 Set
(Replace Lower Control Valve Body Channel Plate and Gasket)

Models:
2000 Cadillac DeVille, Eldorado, Seville
2001 Oldsmobile Aurora
with Hydra-Matic 4T8E (RPO MH1) Automatic Transmission

This bulletin is being revised to correct the part number for the reverse clutch housing assembly. Please discard Corporate Bulletin Number 01-07-30-005 (Section 07 - Transmission/Transaxle).

Condition

Some owners may comment on no 4th gear or it slipping in 4th gear. The "Service Engine Soon" lamp may illuminate. A Diagnostic Trouble Code (DTC) P0734 may be set.

Cause

This condition may be caused by a warped lower control valve body channel plate (900) which allows the loss of 4th band fluid apply pressure.




Correction





Using a Tech 2, check and record any DTCs that are set. Inspect the 4th band (523) and the reverse clutch housing (500) for distress. Replace them as necessary. Also replace the lower control valve body channel plate (900) and the lower control valve body spacer plate/gasket assembly (935).

Refer to the appropriate vehicle Service Manual and Transmission Unit Repair Manual for the proper repair procedures.





Parts Information

Parts are currently available from GMSPO.

Warranty Information





For vehicles repaired under warranty, use the table.





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