Jim Grant's Tech Tips
96
Pontiac Grand Am, Automatic Neutral Transmission
Q: My girlfriend has a '96 Pontiac
Grand Am with 40,000 miles. When leaving a toll booth the transmission
in the car slipped and then caught after a few long yards. The transmission
did it again and then has worked for a long time. The dealer put it on
some machine and said there was nothing wrong so I had the transmission
flushed and new fluid and a filter installed. Now, just a few weeks after
the warrantee on the vehicle ran out the transmission slipped again. It's
still working now. But what was it?
A: That's
a good question. Would the condition best be described as if the car was
momentarily shifted into neutral? GM had some problems with the Hydra-Matic
4T60-E transmission which was used in '96 -'97 Pontiac Grand Am and other
GM products of those years. The problem was with a shifting valve inside
the transmission sticking causing the transmission to intermittently lose
drive, feels like neutral. In some cases the condition could even cause
the transmission to lock up, which is very damaging. ALLDATA Information
Systems shows Bulletin No. 67-71-64 addressing this condition and the
fix requires replacement of the control valve body assembly of the automatic
transmission with updated control valves.
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