thump and hard jerk in transmission

gamagama Member Posts: 2
edited April 2014 in Saturn
My Saturn SL-2 with 42,000 miles (I purchased extended warranty from dealer) started shifting hard and at one point jerked so hard I thought I had been hit in rear end. Took it to dealer and of course this is not a consistent problem and they couln't find anything wrong. Very frustrating as vehicle is still doing this (not consistently) It seems to happen more frequently in heavy traffic and stop and go situations. I'm back to the dealer next week and in meantime feel very uncomfortable driving the car. Automatic transmission and seems to be worse from 1st to 2nd, but not good from 2nd to 3rd. Have driven today and shifts smoothly. But tomorrow who knows- please help - I think the dealer thinks I'm imagining this!!


  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    You might try an oil and filter change, but really, this doesn't sound too good. Something is not releasing properly inside. I don't know your particular trans so can't speculate further--depends how it is shifted.
  • gamagama Member Posts: 2
    in response to Mr. Shiftright it has a 4-speed automatic - I purchased the vehicle used in Nov.,2000 and also purchased extended warranty to 60,ooo miles. Drove some today and did not experience any problems, but am afraid to drive too much. I have told dealer when I bring the car in tomorrow keep it and drive it until they experience same problem. Where do I go from there if they don't find anything?
  • theicemantheiceman Member Posts: 736
    Does the problem mostly manifest itself from a stop or from 1st to 2nd or all shift points? Is it only when you accelerate hard whereas light acceleration there's no evident problem? Is it worse once the transmission has "warmed up" (i.e. after a cold start, it's okay but afterwards it's likely to happen). Your problem could be as simple as a tempermental solenoid.

    Can you find out if the tranny has been previously rebuilt? If yes, it's possible that whoever rebuilt put in a shift kit - which increases the pressure and makes that shift from 1st to 2nd more pronounced. If so, this isn't necessarily a bad thing (just off-putting to most) and could in fact mean that your tranny might last longer.

    P.S. watch for your motor mounts - very hard, jerking shifts could weaken or break your motor mounts. Get this problem check out sooner rather than later.
  • poisondartfrogpoisondartfrog Member Posts: 102
    Had a similar occurrance with a '97 Olds Bravada with the 4.3L V6 and the 4L-60E transmission, at 46K miles. The tranny would experience a "slam" on the upshift from 1>2 (the worst slam), 2>3, and 3>4, but only after driving on the highway for say, an hour or longer. The Service Engine Soon light did come on during these episodes. I minimized the slamming effect by using the "2nd Gear Start" feature, until I got fixed the next week. Note: it didn't act up when it was cold.

    The culprit was a worn modulating valve in the valve body of the transmission. Seems GM used the wrong material for the (sliding-spool) valve, and the valve would become oval (instead of round) over time. (According to the GM service adviser, the valve moves very fast while in operation, so I can understand how a bad material choice could wear out prematurely.) This would allow fluid (especially hot fluid - less viscous) to leak past and screw up the pressure for the upshift. Thus, it would "slam". The solution was to replace the valve body.

    Maybe since Saturn is a GM company they used the same brillant design in the Saturn tranny? Hmmm... after all, why are they "general" motors???

    Hope this helps.
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