A/T - 4L60-E/4L65-E Harsh 1-2 Upshift Diagnosis
Bulletin No.: 01-07-30-030BDate: October 18, 2005
INFORMATION
Subject:
4L60-E/4L65-E Automatic Transmission Diagnostic Information on Harsh 1-2 Upshift
Models:
2001-2006 GM Passenger Cars and Light Duty Trucks
2003-2006 HUMMER H2
2006 HUMMER H3
2005-2006 Saab 9-7X
with 4L60-E or 4L65-E Automatic Transmission
Supercede:
This bulletin is being revised to add model years and models. Please discard Corporate Bulletin Number 01-07-30-030A (Section 07 - Transmission/Transaxle).
The following four conditions have been found to cause the majority of consistent, harsh 1-2 shift comments.
^ Chips/Sediment/Debris/Contamination found in the valve body, 1-2 accumulator valve (371) bore, may cause the 1-2 accumulator valve to stick or hang-up.
^ Chips/Sediment/Debris/Contamination found in the valve body, 4-3 sequence valve (383) bore, may cause the 4-3 sequence valve to stick or hang-up.
A cracked 1-2 accumulator piston (56) that is allowing fluid to leak by.
Mislocated/Missing valve body-to-spacer plate check balls (61).
When attempting to correct a consistent harsh 1-2 shift, the four conditions listed above should be inspected as possible causes. It is important to also refer to the appropriate Service Manual for further possible causes of this condition.
This diagnostic table should be used when addressing a harsh 1-2 shift concern.
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