A/T - 4T80E, Harsh Reverse Gear Engagement

File In Section: 07 - Transmission/Transaxle

Bulletin No.: 01-07-30-019

Date: April, 2001

TECHNICAL

Subject:
Harsh Reverse Engagement, 1st Shift of the Day
(Replace Upper Control Valve Body Spacer Plate Gasket)

Models:
2001 Cadillac DeVille, Eldorado, Seville
2001 Oldsmobile Aurora
with Hydra-Matic 4T80-E Automatic Transmission (RP0 MH1)

Condition

Some owners may comment on a harsh garage shift from Park to Reverse during the first shift of the day. The condition will not repeat itself after the first shift of the day, but will return the next day during the first shift of the day. If the customer concern does not exactly match this description, additional diagnostics should be performed.

Cause





Condition may be caused by an unintended transmission fluid pressure spike occurring during the first Park to Reverse shift of the day due to air in the reverse hydraulic circuit (32) being fed into the line pressure circuit (6) across gasket slot number 41, (Figure 1, Item 1).

Correction

Replace the gasket between the spacer plate and the case cover with the new style gasket that has eliminated the gasket slot number 41 (Figure 1, Item 2). The new gasket has a white stripe across one side (Item 3) to help identify it as the new style gasket in the production assembly process. A "Service Only" kit, P/N 24221401, contains the new gasket. Early kits contain gaskets taken from production inventory and have white stripes. The white stripe is removed in later production and later gasket kits.

Parts Information

Part Number Description Qty.

24221401 Gasket Kit - Control/Valve 1
Body Spacer Plate

Parts are currently available from GMSPO.

Warranty Information





For vehicles repaired under warranty, use the table as shown.





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