violent shuddering on take off

[StayGold808]

Hi,

When i move off in 1st gear, sometimes i get a VERy violent shuddering, where the whole car is shaking and the gear lever is shaking.

It doesn't happen always, but atleast once each time i drive the car, sometimes more.

I.e, when moving off, you engage the clutch just enough to get the car rolling, and when the engine revs match the wheels, you can let go of the clutch pedal completely. The shuddering happens when the revs are almost matched.

It also has a much greater tendency to happen when the car is on a steep incline.

Thanks Alot!,
Adam

[slodave]

I get this as well. Old clutch - well at least in my case.

[Todd Simpson]

Your clutch could be contaminated with oil, creating a situation where it grips/doesn't grip very quickly.

Another possibility is a broken motor or trans mount on the left side. Check all 4 mounts to be sure.

[POKDUB]

Bet on transmission mounting nuts loose.

[ChemMan]

Have you changed your clutch cable recently by any chance? Mine did the same thing. Adjusted the cable and everything was fine.
Mike

[Mothy]

I have had the same on mine exactly as you describe. In my case it was some oil on the clutch plate (leaky seal) plus having a VERY steep curved drive into my garage = need to slip clutch = burnt clutch.

If you had an old sedan, you'd swear it was axle tramp!!

Even had it on my WRX - one day I'll learn to use a clutch properly.

Tim

[Jeff]

Adam, You need to adjust your bowden tube and then adjust your clutch cable.

[safe]

Originally posted by Todsimpson
.....Another possibility is a broken motor or trans mount on the left side.....

Why on the left side??

[DW SD]

Originally posted by C U L8R
Adam, You need to adjust your bowden tube and then adjust your clutch cable.

I agree with Jeff! I had the same issue a year ago until I tightened the bowden tube against the firewall.

10 minutes, problem solved. two 15 mm wrenches.

Doug

[norustscott]

I suspect it is the mount that is pulled apart rather than compressed?

[Todd Simpson]

Why on the left side??

This will happen with the front trans mount, I'm not sure about the rear.

If one of the mounting bolts is lost, the engine and trans will drop a little on that side.

Due to the rotation of the engine, the engine and trans twist counterclockwise under load. If a right side bolt is missing the load has the effect of "fixing" the problem by pulling the engine up to the mount. The clutch engagement seems a little slow, but once that mount moves up it feels normal.

The left side under load will continue to pull away from the mount, then spring back producing the juddering.

Just a funny thing I've noticed on 3 different cars. Certainly all the mounts should be looked at.

[StayGold808]

I did suspect it could be oil on the clutch plate....

i didn't replace my clutch cable, but i did have to disconnect it then re adjust it after fixing my pedal assembly...

Ok, i did some reading on what the bowden tube is, but could somebody tell me how to adjust it? I'm not sure if i'm thinking of the right part.

Thanks for the help everyone

[Miguel Antonett]

Loose/slack clutch cable.

[DW SD]

You need to force curve into cable by loading it against the firewall Mine arches above and away from the throttle bellcrank. It is adjusted with the 15mm nuts where the clutch cable attaches to the tranmission.

[cliyde]

I had this EXACT same problem a while back... even posted a question on the PCA website. I replaced 22 yr old motor/trans mounts and re-adjusted the clutch cable. Problem solved!
Good luck with it.

[StayGold808]

thanks alot to every1 who helped. I adjusted the bowden tube a bit, and problem solved.

As a by-product, the clutch engages over a much shorter distance, and hence the meeting point is much higher now. How high is it supposed to be? Because i used to have mine much lower, but my brother has a boxster, and his clutch engages about the same as my 911 after the adjustment.

Thanks alot!