Shimmy when accelerating, only in last gear.?

Question

I have a 95 Galant S automatic.

Recently, it developed a violent shimmy when accelerating from 55-65 MPH, or when attempting to maintain speed over 55mph while going up a hill. Once I got over 65 on relatively flat land, it would drive smoothly again.

I brought it in to have someone look at it, they said it was a bad transmission mount and replaced it. It worked fine for a good 50 miles through the Appalachian mountains, then went back to what it was doing, though not as severe.

I realized that it happens at 55-57MPH because that is when it switches into the last gear. It usually only happens between 2500 and 3000 RPM, unless I am going up a hill. Then it does it all the way up to about 3500.

This is only when accelerating. When I am coasting during those speeds there is absolutely no vibration.

Any ideas? The repair shop was not of much help.

Answer 1

You may want to start with getting your transmission "Flushed", make sure they get the fluid out of the Torque converter -this needs to be done at a local oil change stop or trans shop.

This sounds like the Torque converter needs fresh fluid, and doing this may fix the trouble your having.

If not, you may need a complete transmission Diagnosis...

Best wishes!

"/JOe

Answer 2

i can think of 2 reason why it would do that 1: you might have bad u-joints does it clunk when u shift ? if not that then it for surely is ur drive line all drive lines has a balancer on them if you dented or some how tweaked your drive line it will shake ur car at certain speeds when under load