Transmission clunk/thump???

[davew833]

I'm trying to diagnose a moderate transmission clunk/thump in the '95 LSi I just got. It happens immediately after accelerating from a stop if I'm not extremely gentle on the gas pedal. At first I thought it was just downshifting hard into first as I accelerated, but it also happens if I put the gear shift is in "1". I also put the FWD fuse in to see if that made any difference, and it still made the noise. It seems to be coming from directly under the shifter, or maybe slightly behind it. I probably wouldn't have noticed it, except my '92 doesn't do it at all.

Interestingly, I found a dealership service order from 1999 showing the previous owner had the same complaint(!) The dealer was "unable to duplicate the problem". The transmission seems to shift fine, but I think the thump will drive me crazy if I don't know what it is. Any suggestions? I'm thinking maybe a broken trans mount...

[Budfreak]

Originally Posted by davew833

I'm trying to diagnose a moderate transmission clunk/thump in the '95 LSi I just got. It happens immediately after accelerating from a stop if I'm not extremely gentle on the gas pedal. At first I thought it was just downshifting hard into first as I accelerated, but it also happens if I put the gear shift is in "1". I also put the FWD fuse in to see if that made any difference, and it still made the noise. It seems to be coming from directly under the shifter, or maybe slightly behind it. I probably wouldn't have noticed it, except my '92 doesn't do it at all.

Interestingly, I found a dealership service order from 1999 showing the previous owner had the same complaint(!) The dealer was "unable to duplicate the problem". The transmission seems to shift fine, but I think the thump will drive me crazy if I don't know what it is. Any suggestions? I'm thinking maybe a broken trans mount...

Sounds like the carrier bearing or u joint on the driveshaft or trans. mount is shot. Could also be the rear diff.

[dannmarr]

Sounds like the carrier bearing or u joint on the driveshaft or trans.

I agree. When my car had this problem it was a bad u-joint and a worn yoke on the drive shaft.

[crotchrocketony]

Im going to put my money on the rear trans mount.....

[davew833]

I got under the car last night, and there is some play in the front u-joint, but I also found I could easily push the tail end of the tranny up off the crossmember/mount. I'm guessing it's not supposed to do that! Since the tranny mount is slightly easier/cheaper to change, I guess I'll start there.

[crotchrocketony]

once again im going to say it is your trans mount...there is not supose to be play like that in it. what you hear is the trans hitting the bolt that stops the trans from hitting the floor when the mount goes bad like yours is....save like $75 on the mount by going to subaruparts.com its like $80 there but if there is play in the ujount....replace it...it isnt cool when they go bad all the way.... I saw a truck flip from the u-joint breaking on the highway

[Shadow_Myst]

My car has a very similar symptom... that is exatly like the trans mount. Good luck and let us know if it solves your problem.
-=Chris

[davew833]

Well, Budfreak is sending me a good used tranny mount, but I also tightened up that center bolt that keeps the tranny from moving upward too much and it solved the problem, at least temporarily. I guess it's a good indication that it is, in fact, the tranny mount.

[Ricochet]

Does it get faster with speed, rpms, or is it constant?