LG John

I took my car to a garage that my mum works for this morning and myself and one of the mechanics took it for a spin so I could demonstrate the drivetrain clunk. The best way to demonstrate it is to cruise at 30mph in say 3rd gear and whilst keeping your throttle in the same position you ping the clutch so that it disengages and engages again quickly. As it engages it causes a shunt and the double clunk can be heard from roughly behind the gear leaver/gearbox area. The mechanic immediately thought it was an engine mount when he heard it.

We got the car up on the ramps and inspected the mounts and tested them for play but they were all fine and there was no signs of metal on metal impact. We checked the gearbox and its mounts and they seemed fine also. We then did another test: with the car raised, the mechanic underneith it and the hand+foot brake on I'd let her idle in 2nd gear with my foot on the clutch and then side-step it (thank god the brakes held btw!). This would instantly stall the car but would obviously shock the entire driveline - I could hear the trademark clunking from within the car but the mechanic couldn't see anything obvious.

Things he did notice:

1. There was a lot of movement in one of the rear suspension bars (up and down). I told him that I believe this is a case of 'they all do that' as you can hear that bar juddering on nearly all scoobys leaving the line at crail/pod/etc. We both agreed the noise wasn't coming from that far back anyway.

2. He felt the gearbox has a lot of movement in it but didn't know if it was normal. He said it was kicking up by 3 inches roughly but wasn't obviously hitting anything.

3. He said the whole drive system appeared to have a fair bit of movement and play in it but again has no point of reference.

He asked me to post to see if anyone has experience with this and if that sort of movement in the gearbox is normal. Also does anyone know the price of, and where you can buy a lower gearbox mount - visually the existing one seemed fine but depending on price it might be worth fitting a new one to see if it helps.

A little later we noticed a top brace between the top of the gearbox and the bulkhead so we removed the intercooler to check that. Again it seemed ok with no signs of foul play.

Suggestions welcome? It's not been getting worse in the time I've had the car but the mechanic agreed that if I try to sell it most/all people would be instantly put off and its not that hard to recreate in normal driving.

We were also considering raising the car on a different set of ramps which actually leaves the wheels free spinning. Would it harm the car to drive it up to 20-30mph wheel speed and recreate the noise? Would having no load on the wheels cause problems with the diffs? Would all 4 wheels spin or is the centre diff not a limited-slip? Is there any risk of the general momentum created by wheel movement jumping the car off the ramp?

silent running

Clonk can often be the dogbone mount that you found attached to the bulkhead, but pretty much any of the mounts being loose will have the same effect.

I'm no drivetrain expert, but a movement of 3 inches sounds a lot to me. Fits with the idea that one of the gearbox mounts is loose or even missing?

LG John

That's interesting because we did feel it was coming from that area. The rubbers weren't obviously split or perished though How much is it to buy a new mount - if it's not too much it might be worth a punt.

silent running

It's too expensive to play guessing games with. I think to be honest it would be obvious if the rubber had gone on it. Have you looked underneath at the cross support that goes under the box? When I had a missing bolt/nut in that cushion under there, it clonked.

LG John

Thanks s/r - any other suggestions or opinions? The support under the box and the lower rubbers that attach to it looked fine visually.

johnnyroper

3 inch of movement is way too much my gearbox feels rock steady if trying to move by hand.
the gearbox can be moved slightly if using a prybar but substantial resistance from moving against the rubber mounts can be felt.
i would say you have defo got a worn mount if it moves 3inch like you say