Sudden knocking noise from transmission tunnel

[rover-2000]

Guys
Driving along at 30mph tonight in the Touring and suddenly a severe knocking noise started-sounded like a wheel coming off.....

Pulled over and checked the wheels-all tight. The noise sounded like it was coming from the transmission tunnel.
I dont know the E30 too well-what could be causing a sudden heavy knocking noise? Prop joint maybe? Is there a bearing?
Nursed it home (Was only 1/2 mile) but not too sure what to check.
All advice greatly appreciated!!

[torquey]

Had the same type of thing,turned out to be the diff mounting bolts had come loose so check them.

[peeweemad]

Also check the exhaust clamp that is situated in the trans tunnel area as have had that cause a knocking sound on my car when lose. Hth

[capri_rob]

Prop centre bearing has shat itself by the sound of it.

Not expensive - available from ECP or GSF - you'll probably need to replace the propshaft rubber "donut" whilst you're at it.

[rover-2000]

Thanks guys. Is the rubber donut dealer only ?
How hard are these bearings to change?

[Rav335uk]

Depends on whether it's been changed in the past.
If not, could be a ballache to get the prop off.

[rover-2000]

Need to take it to my mate then I think. Question-is it drivable (Slowly, obviously!) for a couple of miles or is anything terminal going to happen??

[pacerpete]

DO NOT USE Q DRIVE PROP BEARING OR CENTRE COUPLING AS SOLD BY EURO CAR PARTS !!!!!!!
They are garbage as are most Q drive components.

[capri_rob]

IIRC GSF do Lemforder prop donuts for about half the price the dealers charge - I bought one from the dealers last year - cost me the best part of £70

I only found out afterwards that I could have got one from GSF

Agree with Pete - check what brand they offer you before handing over cash - Lemforder or Febi Bilstein are what you want.

[rover-2000]

Thanks guys-is it drivable to get it to my mechanic, or am I going to make things worse?

[Grrrmachine]

IIRC GSF do Lemforder prop donuts for about half the price the dealers charge - I bought one from the dealers last year - cost me the best part of £70

that's mental! They're only 17 quid over here...

http://allegro.pl/lemforder-lacznik-wal ... 90071.html

[Brianmoooore]

that's mental! They're only 17 quid over here...

http://allegro.pl/lemforder-lacznik-wal ... 90071.html

Any idea what postage to the UK would be?

They seem to have a wide range of products - you can't buy these in GSF/ECP : http://allegro.pl/ShowItem2.php?item=2103530184

[Grrrmachine]

I'm not sure they'd have your size Brian, but I'm happy to check ;)

If anyone's serious about buying those bushes, then I'll order a bulk load and post them out myself.

[rover-2000]

Guys! Please tell me! Will I be able to drive the car (Slowly and carefully) for about 4 miles without causing further damage?
Thanks.

[Grrrmachine]

Impossible to say if we don't know what the problem is. If it's something loose then it could break off at any moment. Best get underneath with some spanners and work out if anything is loose.

Remember that because this is RWD, if you tow it it will all still be rotating, so you either risk driving it or you get it trailered.

[KimH]

I fubarred both the Prop centre bearing and the Guibo doughnut between the prop and the gearbox when I had to replace the diff on mine with a smaller one and overtightened the flange bolts, this was at 8 am one hour beforee the car was booked for its MOT

The noise was similar to that which you describe and, yes, I did drive it very carefully to the MOT station and back home again.

Unless you are unlucky - the worse thing that will probably happen is that you lose drive and become stranded.

If it is the drive train that has failed, buy the best parts you can afford, and you might as well replace both while you're there.

[rover-2000]

Thanks for that. I think I'm going to risk it. One question-I might as well get the lot done-is there only one "doughnut" and one centre bearing/mounting?
Many thanks.

[capri_rob]

Thanks for that. I think I'm going to risk it. One question-I might as well get the lot done-is there only one "doughnut" and one centre bearing/mounting?
Many thanks.

Yes

Prop donut joins the front end of the prop to the gearbox - if its never been changed or messed with there will be a metal "vibration dampener" in place - throw it away you don't need it.

Centre bearing is in the middle of the propshaft and bolts to the underside of the car - make sure if there arent existing markings on the prop that it is marked up before its separated to remove the centre bearing so that it can go back together in exactly the right place - otherwise it will be out of balance.

[mrLEE30]

there are two types of centre bearing, they have different hole spacings, ensure you get the right one.

then once the new bearing is back on (taking care to mark the prop when you split it to go back togther in the same splines) you can see the mounting holes are slotted, fix the front and rear prop bolts and leave the bearing finger tight, then last job is to slide the bearing housing about 5mm toward the gearbox, this stretches the rubber mount for the bearing and preloads the bearing, tighten the centre bearing in the pre-loaded postion.

[rover-2000]

Right-now I AM Confused!!

My mechanic had the car on Monday to look at this. I drove it to his house-not as noisy as before but occasional knocking and bearing type "shushing". Left it with him

Just spoken to him. He took it to his garage and put it on a lift, removed the shielding and found.....absolutely nothing wrong.... He has checked both the centre bearing and the doughnut on the prop and says they are both recent replacements-no cracking to the rubber or evident wear at all.

He put it back together and took it for a 30 min drive-no noise, no knocking, nothing. He then got his mate (Another mechanic) to do the same and neither of them could find anything wrong. They even checked the driveshafts just in case.

So there we are. I know I wasn't dreaming-and I had my kids in the car when it started and it really did sound like a wheel was coming off or something. I can only imagine that something might have got caught on the prop ?

We shall see if it returns .........