violent shaking in reverse

[greengiant]

as the title states. And by violent I mean VIOLENT! its very odd, its done it every once and a while since I bought the car over a year ago. seems to be more when its in that high rev stage after it first starts. it did it really bad today twice and it made me really nervous. A group of people 30ft away backed up, they said everything in the front was moving. it doesn't have any issues really going foward. two of the torque dampers are missing which I plan on fixing this winter but I don't think that would make this amount of shaking. I checked the motor mount last fall and seemed fine so i'm confused. I also checked the subframe bushings and they are great.

 

[AREA 91]

I can think of a few things.
The clutch itself could be glazed or contaminated (oil).
Sub frame bushings
Motor mounts
Tranny mount

 

[sperold]

Clutch issue. This is stage 1. Start looking for a deal on a clutch kit. You don't have to rush as you have lots of time left.

 

[greengiant]

I can think of a few things.
The clutch itself could be glazed or contaminated (oil).
Sub frame bushings
Motor mounts
Tranny mount

-tranny is fine, I know that for a fact, subframes too
-motor mounts I don't know
-my clutch was very stiff during the summer but I only drove it every once and while since its not my DD and I don't drive it in the winter. Now I'm up at college and I'm driving it alot more and the clutch pedal has been getting looser and it shifts much smoother now, but it doesn't have any slipping feeling to it, it's just soft.
if there was oil on it how can I get it out?

 

[Racer X]

I can think of a few things.
The clutch itself could be glazed or contaminated (oil).
Sub frame bushings
Motor mounts
Tranny mount

So...

This is happening to someone I know out on the island, and it happened to me a little last night while reversing into my driveway. In my case, it's controllable if I rev up before releasing the clutch, but if I try to slip the clutch as low revs, say 1200 or so, it'll eventually begin to chatter enough to cause the whole drivetrain to convulse, for lack of a better term. This doesn't occur in 1st gear.

It's not oil, as I have no leaks, and the rear main seal, carrier gasket, and input shaft seal are all brand new.

SFB's are Al, mounts are 5 years old, but they're braced HD at all 3 corners.

I'm not super worried about it in my case, but for the guy I know on LI, his car is to the point where he just can't use reverse anymore. Any attempt to clutch out in reverse, high revs, low revs, slip the clutch, side step the clutch... you'll shake the teeth right out of your head.

Replacing the torque dampeners didn't do anything in his case either.

Granted, his car has a few... well, let's call them Easter eggs for now (full story coming soon in the Hall of Fame or Shame forums), so it's likely that he may have a clutch or FW issue, or oil contamination (or both?). But if this is the case, any ideas why the chatter would only happen in reverse, and not when engaging 1st gear? We floated the idea of a clutch issue, but I couldn't get my head around the idea of it only presenting in reverse, and not in 1st as well.

 

[sperold]

My theory is the gear ratio is much higher in reverse. And usually you are backing uphill, like a sloped driveway or something similar. One thing that could be done is, try taking off in second or third and see if you can approximate the feeling.

 

[greengiant]

-Hamal,
so what you're saying is this could be one of those sho things you just have to deal with like dim headlights, rattling interior and dead steering spots

Sperold
I take off in second all the time, the way the town is its slightly sloped most of the time. I've never noticed anything

 

[1993MTXSHO]

It's you're engine mounts I would almost bet anything on it. My old 94 mtx did the exact same thing. Sometimes it was fine, others it felt like the car was going to rattle apart. Fix it now, my car ended up cracking the tranny case because of this.

 

[LJRuddy]

Had this same problem with my car...

It was a combo of a bad rear mount and a bad tranny mount.

 

[lowc]

same issue in mine right now and i know i have a bad rear motor mount all other mounts and bushings are good although im sure ill need a front mount soon enough

 

[Racer X]

My old 94 mtx did the exact same thing. Sometimes it was fine, others it felt like the car was going to rattle apart. Fix it now, my car ended up cracking the tranny case because of this.

No kidding. How'd you fix it?

 

[shotime1994]

It's you're engine mounts I would almost bet anything on it. My old 94 mtx did the exact same thing. Sometimes it was fine, others it felt like the car was going to rattle apart. Fix it now, my car ended up cracking the tranny case because of this.

X2 I would like to know the fix as well.

 

[greengiant]

x3 on that

 

[LOUDSHO92]

I think he just said, its the motor mounts. So replace the motor mounts.

I think the rear is the bigger culprit unless the front has failed as well.

 

[shotime1994]

I have been working on a sho that has the same problem. I replaced the motor mounts and trans mount. The transmission was also replaced because the case was cracked where the trans mount bolts up (thanks Nick). It is a clutch and flywheel issue I have narrowed it down to.

 

[SinisterSHO]

my clutch chatters in reverse because its a 9 puck

 

[Mike93]

Gonna bump this...

I occasionally run into this issue with my car as well...however I had always attributed it to the atx-mtx swap I did...guess it wasn't me screwing something up!

With the following, I experience clutch chatter in reverse:
*brand new stock clutch
*alum. sfb's
*all mounts are made solid with large nuts/bolts keeping them from literally any movement

In all my SHO experience, I can honestly say I don't know the cause of this. I'd be curious to know if people are still running the stock mtx dampers and still having an issue...

 

[greengiant]

i will be checking and replacing my motor mounts and torque dampers this spring to see if it helps the problem