[Transmission] Unusual G/Box / Drive noise

[Diver637]

Hi Everyone,

I've been reading the forum since last year when I bought an 03 1.9 van (150K miles) I've only just registerd to post though.

The van is in need of a clutch as the pedal is getting closer and closer to the floor so its been on the agenda to fit a new one.

However, recently when I was driving along the motorway (60mph ish) I pulled out to overtake and accelerated. I must admit the radio was on loud so I didnt hear the noise at first but the van seemed to loose power and the tacho whent up in speed. At first I thought that somehow I'd managed not to engage top gear and it had droped out of gear. After decelerating the drive came back and I reduced speed and then carried on as normal.

Since then I've noticed intermittantly there is a loud grating sound (in any gear) and loss of drive momentarily until either dipping the clutch or decelerating. And it is very intermittent, in fact if I drive without any hard acceleration it hardly does this. And turning corners (ie parking etc ) doesnt seem to affect it.

The noise sounds like either two gears not quite meshing or a gear that hasn't engaged fully and the synchro has baulked. But there is no bearing noise from the gearbox, it drives without any gear change issues, the noise / problem can be in any gear.

If the vehicle was driven and the fault didnt occur you would not know there was any problems. When I drove it yesterday I did about 10 miles and the fault didn't happen.

So to that end I'm slightly foxed.

I'm intending to take the gearbox out as it needs a clutch and whilst doing that drain the gearbox oil to see if there is any evidence of swarf etc in the oil that might be a clue. Also I was thinking that at this mileage there might be a worn engine mounting causing partial gear disengagement under different acceleration. I was even considering the differential as the fault is indicative of something that is in permanent drive all of the time but I would of expected some bearing noise beforehand and from experience, differential faults are usually there all of the time.

As I said it is not in any particular gear or happen all of the time.

Just wondering if anyone has encountered these type of symptoms or fault.

Many Thanks


PS an excellent forum.

[brodfather11]

oops Sounds expensive £££££

[Diver637]

Thanks,
Hopefully not that expensive as I'm in the trade and have a fully kitted workshop . Its just any pointers before I start pulling things to pieces. Its always useful if someone has had the fault and if there are any common areas to focus on.

Cheers

[Noel Brig]

The van is in need of a clutch as the pedal is getting closer and closer to the floor so its been on the agenda to fit a new one.

However, recently when I was driving along the motorway (60mph ish) I pulled out to overtake and accelerated. I must admit the radio was on loud so I didnt hear the noise at first but the van seemed to loose power and the tacho whent up in speed. At first I thought that somehow I'd managed not to engage top gear and it had droped out of gear. After decelerating the drive came back and I reduced speed and then carried on as normal.

Since then I've noticed intermittantly there is a loud grating sound (in any gear) and loss of drive momentarily until either dipping the clutch or decelerating. And it is very intermittent, in fact if I drive without any hard acceleration it hardly does this. And turning corners (ie parking etc ) doesnt seem to affect it.

The two bits I have highlighted above in your post are classic examples of a worn out clutch. Often the first signs of a worn out clutch are in a high gear at speed going up a hill.

Basically the friction plates have worn away and no longer provide the grip to hold the engine to the gearbox. You have probably worn it down to the rivets and it will be these that are making the grinding noise!

Interestingly the reason you give for thinking you are in need of a new clutch - "the pedal going down too far" Is not in itself a sign of a worn out clutch, the pedal mechanism should be self adjusting and the feel of the pedal should not have changed - may be it is just a problem with the pedal/cable, although the noise sounds like the rivets which means you need a new clutch - Maybe the problem with the pedal has caused your clutch to fail!

Good luck, and let us know what happens

[craigblues]

What he said above. :-)

[Diver637]

Hi Noel,

Thanks for that, I can see my description would sound like a slipping and worn out clutch and it would be nice if it turns out to be that. But if the clutch friction linings had worn out completely it would be relatively easy to initiate the fault. And I can see by my explanation it sounds like a clutch slippage problem. But generally with clutch drive slippage I would expect to have the usual smell of burnt friction linings from the driven plate and also the slippage sensation is similar when it happens to driving a vehicle with an automatic gearbox ie applying throttle and a delay in drive being taken up. (when this happens its sudden as if its been pulled out of gear)
Also if it had worn out then the fault could be replicated over and over again. I have also thought about clutch slip and tried to set off when its warm in a high gear. Usually if theres any slippage then that will usually identify it.
All the vehicle does is behaves like it is in a gear to high and drives away without slip. And there is no noise when engaging the clutch it all behaves and drives as normal.

With regard to the pedal height then there possibly is a problem with the adjuster but some vehicles do tend to loose pedal height when the clutch wears and yes in an ideal world with a fully functioning adjuster the height would stay the same. But from experience its all to common on older vehicles for that not to work properly or fail completely.

Anyway its a strange one and in all my years I've not heard anything like this. I had a couple of my mechaics look at it yesterday and they both looked as perplexed as I did.

But we are going to drop the transmission and differential oils today and have a closer look underneath and probably pop the gearbox out.

I'll keep you posted and thanks for you help.

Cheers

[hachiroku]

Will be interesting to see what you find, like the others I would have said the symptoms would suggest to me that the clutch was in need of replacement, and given the mileage on the van it's to be expected.
The revs/engine speed rising but the road speed staying the same is classic sign of clutch slippage/wear, if you're at speed then you may not notice the smell of burnt clutch plate.
The grating noise you mentioned could be the rivets as mentioned, and if the clutch is worn that far down then you'll be lucky if the flywheel isn't trashed too, but it could also be gearbox related, perhaps the syncros are worn. I take it the transmission fluid level is ok?

[Diver637]

Hi All,

Well I've eventually got around to getting the gearbox out. We examined the clutch and it didn't show any signs of slippage. The only potential problems that we identified where the diaphragm fingers were worn (I believe its a common fault for the release bearing to wear through these) the friction plate was getting near the end of its life but hadn't worn out completely there was about .5 mm of lining left on both sides so the rivets had not touched the flywheel or pressure plate. The release bearing was worn but nothing unusual. But the centre plate had rather a lot of movement in the centre compared to the new one. Everything else was fine, drive joints, cables etc etc. Also there was no visible material in the old gearbox oil. The pedal height issue is possibly going to be the self adjuster.

So all new clutch( 3 parts) and arm fitted and road tested ....... guess what .......It did exactly the same!!!

45 mins later the gearbox was back out and going to be stripped. On draining the fresh oil out of it there was a tiny amount of metal particles in the oil. And I mean a miniscule amount. But this is probably an indication of something failing in the transmission. But there was no external evidence looking at the outputs or feeling for roughness turning the input shaft. On the roadtest I managed to have the transmission make the noise so I pulled over tried the clutch in and out and the transmission in and out of gear and the noise was matched to the engine speed. With the vehicle in gear and the clutch raised there was no drive until the engine was stopped and gear re-engaged and engine re-started then it drove away as normal. And this can be in any gear, so its something common to all gears and the engine ie input shaft or something in that area.

So I'll keep you all posted.
I did say it was a strange one

[ffrenchie]

If it's in all gears it sounds like a differential fault which would explain loss of drive. Probably stripped some teeth off a gear or a pin partially worn.

[Ol'Jeffers]

I would have thought along the lines of a CV joint getting tired..