Strange clutch / gear change behaviour

[s2_bo]

Hello.

I noticed last night while driving that there was suddenly some vibrations during gear changes, at first it felt like they where coming through the clutch pedal but i went for another drive just now and it feels and sounds like they are coming mostly from the back of the car but also a bit from the front.

If you let the clutch slip gently in 1st on a hill start it judders and vibrates just on the biting point. Same happens when you change in to 2nd but less and so on. Also in reverse gear if you slip the clutch it vibrates the same.


It feels like the clutch is uneven and its not biting properly.

Anyhow i got under the back of the car to see if everything was tight. All the mounts were tight apart from the rear diff mount. The bolt that goes through the center was not very tight. I tried to tighten it but the nut on the other end is just spinning. Wont come lose anymore but also wont tighten.

The nut and bolt in question are:
N 021 195 5 - M10 self locking
and
N 010 472 11 - M10 x 85mm

Also looks like the rear diff mount has been moving around a little in its casing as there are slight marks from where the silicone has rubbed the dirt away.

Could this be the problem to the vibrations? Or does it sound like its defiantly clutch related. This morning the pedal felt fine so I'm ruling out MC or SC for now.

Any help would be much appreciated.

[Acidburn]

I'd start with sorting the rear diff mount out as that will be making a difference, do you feel more klonks etc when changing gear?

[s2_bo]

Not really no, just the vibration but it only started yesterday night.

[QuattroFever]

i had the same symptoms when my clutch friction disc broke up.
when was your clutch last done?

drove ok but juddered on the biting point.

any moaning/groaning noises?

[s2_bo]

No other noises.

Clutch is a St3 clutchnet one. its done about 15k and I checked it about 2k ago when the engine was out, all looked ok with loads of surface left.

Is there any way to test if the friction plate is still ok? I really hope thats not the case as i dont have the tools here to change the clutch again.

I cant change the center diff mount bolt and nut yet as i need a hard point chisel to split the nut, its just spinning on the spot. I think the wrong type was used when the Poly bushes were fitted as its not a self looking one.

[QuattroFever]

anything happen leading up to the vibration? hard acceleration or anything.

SM or DM flywheel? can you see the edge of the clutch plate from the window in the bellhousing

as above tho....main suspect is prolly that rear diff. mount if you say the majority of the vibration is at the rear.
so no sweat, no ones luck is as bad as mine.

can you get a grip on the nut with mole grips and a hacksaw blade down the back of it?

[s2_bo]

No i was driving normally, so not to hard. But the road conditions here are notorious and i have a very hard eibach/bilstein coilover combo so maybe it shook the diff about a bit to much.

Its a stock 3b flywheel.

I cant get in there with a hacksaw but i do have a hard point chisel, so will use that to try and split the nut.

Got a spare nut and bolt ready to replace it with.

Cheers for the suggestions so far..