After running at highway speeds for 30 minutes or so, when I slow down, the car vibrates hard (seems to be staying in 4th gear) then after the car stops, it slams into first gear. It only does this after the car has been running for some 30 to 40 minutes usually at 45mph or faster. Any help is as always appreciated.

If it's a 960, the torque converter lock-up solenoid is bad. Replace it...it's the only fix. Flushing the trans won't do anything...wait until you have the pan off to replace the solenoid and then flush it.

Lance

If it's a 960, it sounds as if the lockup torque converter is staying locked up. There has been a significant amount of discussion here about that. It's not an unheard of problem with the 960 trans. It WOULD be an unusual problem with a 940 transmission.

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1992 940 wagon, 72k
make people envious; smile often.

940, 960 how many miles?? When was the last time fluid was replaced?
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1996 960 127,507

The car is approaching 80k miles. I dont know if the previous owner ever flushed the tranny fluid. Any recommendation on the type of fluid that should be used?

The only fluid SYNTHETIC. Do a flush.
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1996 964 126,040

Flush the transmission fluid. Do not simply drain and replace -- you have to flush to get all the old gunk out. See the FAQ for directions, otherwise take it to a shop with the "power flush" equipment.

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Matt L. -- Cary, NC -- '89 740 sedan -- '91 740 wagon