what would cause the transmission to shift hard into second an third when engine is hot
- posted
10 years ago
1996 gmc 1/2 ton transmission problems
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- posted
10 years ago
It is getting old and worn. Could be a valve sticking.
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- posted
10 years ago
If a 4L60e or other similar electronically controlled transmission, not to state the obvious but putting a scan tool on it and reading any codes, and watching live data is the logical thing to do. Many codes do not turn on the MIL light but will present drivability issues. Otherwise you are just shooting in the dark.
Hint: the harsh shifts are likely because the transmission is setting the line pressure to maximum. For a mechanically controlled transmission it is possible that there is a problem with the pressure regulator.