A/T - 4L60-E Harsh 1-2 Upshift
Information IB05-05-S0124L60-E Automatic Transmission Diagnostic Information on Harsh 1-2 Upshift
ISSUE DATE: NOVEMBER 19, 2005
Affected Vehicles:
2003-2006 Isuzu Ascender (US/UT)
2006 Isuzu i-280/i-350 (TI) with Automatic Transmission
Service Information
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.
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 Service Manual for further possible causes of this condition.
Slipping or Rough 1-2 Shift
This diagnostic table should be used when addressing a harsh 1-2 shift concern.
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