Thumping when pulling away?

[Shotage]

Hi all.

I have a thumping noise coming from under the van when I pull away. It only happens when pulling away (so 1st gear) and it's a repetative thumping, 4 or 5 times maybe in quick succession. My garage have just done the gearbox mount bushing and I still have the problem. It sometimes also make a bit of a noise when reversing although this is a different noise and maybe completely unrelated.

My mechanic is really good and know his VWs but I just wondered if anyone had any ideas on what to try next? I can't afford to keep replacing things that may or may not be the problem so I hope it's not going to be a big list of things to do as a process of elimination.

We have already checked drive shaft CV joints and they are fine.

It's a 1988 T25 1.9 DG (Auto Sleeper).

Thanks so much.
Andy

[kevtherev]

It's probably clutch judder or worn engine mounts... or both.
Does the noise go away if you dip the clutch

Clutch judder is caused by oil getting on the flywheel, usual suspect is the crankshaft oil seal.
A tell tale dribble will be coming from the bottom of the bell housing.
If you can rock the engine by hand easily then the mounts are shagged.

[Shotage]

Thanks so much Kev.

I think the noise does go when diping the clutch, yes. It really is just as the clutch is engaging so would make perfect sense.

I think my guy checked the engine mounts but will double check that.

I will look for this tell tale dribble of oil. Sorry, but where is the bell housing?

Many thanks,
Andy

[Smcknighty]

Anyone working on the van whilst you pull away? That sometimes causes a thump thump thump and yell of stooooppp

[kevtherev]

The bell housing is on the rear of the engine or the front as you look from the rear.
It's bell shaped.

[CovKid]

Yep, my money would be on engine mounts - or one bolt holding gearbox/engine together not tight. Broken mounts hard to spot when engine is in situ. May need to remove rear cradle and check them. Judder in 1st and reverse symptomatic of this. Hopefully its not the clutch.

[Shotage]

Thanks so much for your help guys.

I will get these checked out and report back.

All the best.
Andy

[kevtherev]

Thanks so much for your help guys.

I will get these checked out and report back.

All the best.
Andy

Hopefully your "guy" will be sober this time.
Pretty standard stuff, and very easy to remedy, no space to do this yourself?

[Shotage]

Pretty sure the bellhousing was clear from oil.

I tried to rock the engine and there was some movement side to side, but I'm not sure how much you are supposed to be able to move it? I guess it should have some tolerance. I could probably rock it by about an inch or so.

I'm short on time, ability, space and tools Kev
I really don't mind doing the really simple stuff but changing engine mounts sounds above what I might be able to do. What sort of tools do you need?

Thanks,
Andy

[what2do]

Pretty sure the bellhousing was clear from oil.

I tried to rock the engine and there was some movement side to side, but I'm not sure how much you are supposed to be able to move it? I guess it should have some tolerance. I could probably rock it by about an inch or so.

I'm short on time, ability, space and tools Kev
I really don't mind doing the really simple stuff but changing engine mounts sounds above what I might be able to do. What sort of tools do you need?

Thanks,
Andy

A jack and ramps, sockets and spanners. Some round pointy bars for lining up the holes and that's about it. Extra pair of hands for a minute or two here and there. I'd classify it as 2 mug of tea difficulty rating

[CovKid]

If you support the engine on a jack or axle stand/wood and undo the cradle at each end, you should soon be able to see if rubber mounts have split or become detached. If they're fine, reattach carrier. If they are worn out, replace them.