The gearbox in our van is making quite load rumbling noises, which seem to have got worse recently.

The rumbling noise is there from start up when in neutral - it goes away when the clutch is fully depressed. The noise seems to get worse when pulling away - either stationary or accelerating, or engine braking. If you press the clutch when travelling the noise goes away even if it is still in gear, the same goes for coasting - until engine braking begins.

I don't think it's as bad in reverse - but i just might not have paid as much attention

Gearbox oil was changed a few weeks ago which seemed to make it worse I got a local garage to do it while they were checking the carbs and timing. They put standard 80/90 hypoid in.

I changed the oil again this week for peace of mind - this time with Fuchs Titan synthetic 80w90 Hypoid and stuck in a tube of Forte diff treatment too. This seems to have quietened it slightly but not much

The magnetic drain plug was a bit furry when I pulled it out - not sure if the garage cleaned it the other week though There were no big lumps or gritty bits just small silver flakes - more like copperslip type consistency.

Gearbox is a 1500 beetle unit (AH I think) mated to an 2007cc engine - bus is straight axled.

The box came from Jonesy at Boatyard buses (He didn't rip me off either, got rather a good deal actually ). John Walklett then gave it a once over and welded 3rd and 4th - he said it looked to be in very good condition.

The S/A conversion was done by a guy in Leeds around April time last year.

We've done around 6-7000 miles on it since then.

Any suggestions / questions welcomed.

Cheers

Sounds like clutch release bearing...

yep, that's the most likely cause, although I have had the same noise from the input shaft bearing. Mind you that was on an old gearbox.

Cheers,
Dom.

I'd hazard to guess the same clutch release bearing!

That seems to be the general consesus - which is good, at leat it ain't the 'box itself. Afterall the engine is only 4 bolts

I've had a release bearing go before - but it made noise when the clutch was pressed, not when fully engaged??

I thought that the release bearing didn't do anything when the clutch was fully engaged? Just trying to understand the cause.

Cheers!!

check the wheel bearings (fingers crossed).

release bearing. this has been a common fault for a few months, some below standard bearings being used.

what im guessing at and im no gearbox guru, is that the input shaft bearing (inside the gearbox) has failed/ failing. where the bits stuck to magnetic plug fines or more like flakes. the bigger the particals the sooner the fail and the more expensive the repair.

edit the fines/flakes on the plug after 2 weeks is a bit of a pointer, have another look

mark

Cheers for the suggestions.

Wheel bearings are ok - besides - the noise is there when stationary, in neutral with the clutch up - and when travelling with the clutch depressed.

Release bearing seem to be popular - I just can't understand how? The noise disappears when the release bearing is being used and loaded up - surely if it was failing it would make some sort of noise then? It doesn't "feel" like that sort of noise.

Input shaft bearing sounds, unfortunately, more likely - the noise is there only when there is some sort of loading between the input shaft and the engine. ie. Setting off, accelerating, engine braking. Bugger.

I'm not sure whether the garage cleaned the plug? So it's either 2 weekd of build-up, or 7000 miles. I would say a mix of fines and very small flakes - you couldn't feel the particles in a gritty way, just see them.

Cheers.

id drop the oil again and fingers crossed it'll be clean.

http://i98.photobucket.com/albums/l261/ ... G_0070.jpg

this is a pic of t25 one (nicked off 8090 ) from a gearbox that has no problems. unkown service history so it could be 2yrs or 20yrs of wear and this is considered to be a normal collection.

mark

Cheers for the pic - there wasn't much more than that on mine really, although the magnet on mine is flush with the bottom of the plug so it collected in the recess so maybe a wee bit more. Consistency-wise it looked similar.

I'll try and drop the oil tomorrow and see what it's like then. Trouble is I'm away with work from tomorrow afternoon for a week - and then supposed to be taking the van to Europe as soon as I get beck next Friday hence the questions on the gearbox!

One thing I did notice today after taking it for a decent drive out - the noise seems to get less once everything has warmed up. I pulled up and left it idling in neutral and all you could hear was the engine - the rumbling had gone? It was also quieter when driving too?

well there's only one thing for it......turn the radio up


mark

I realise this is quite an old thread, but I have a very similar rumbling noise - in neutral or in gear with the clutch pedal up, disappears when the pedal is depressed. Did you ever figure out what caused your noise?