Hi all,

I've got a 99 manual Polo. It's been making a metallic grinding noise that has been getting worse over the last month or so. The noise is:

- proportional to the wheel rotations (hard to tell if at the same rate)

- ie => independent of engine speed

- independent of gear

- unaffected by braking or not

- greatly reduced when the clutch was depressed (hard to tell if it's completely gone)

- greatly reduced when in neutral with the clutch pedal up (hard to tell if it's completely gone)

I've had the car on axle stands without wheels, brake pads, brake calipers and brake disks and the noise still happens when I drive the driveshafts.

I thought it was going to be the clutch release bearing, but I've now got the gearbox out and the clutch release bearing seems fine to me, although I'm not an expert. The worrying thing is that when I drive the clutch spindle I can hear a noise from inside the gearbox.

My questions are:

- should turning the clutch spindle drive the driveshaft plates super-smoothly?

- what do you think the problem is?

I really don't want to have to get a reconditioned gearbox...

Any help would be much, much appreciated.

Thanks,

Scott

A similar thing has just happened to myne, reconded gearbox was what was needed.

that is the bearing on the end of output shaft nr diff has failed due to lack of oil

a common fault due to lack of maintanance from new the bearing costs £12, but if its foooked the shaft is £175 plus fitting plus any thing else its foooked

Hmm, thanks for the advice.

I'll try opening up the differential at the weekend. Very carefully.

Two more questions:

- are there any online diagrams/instructions of the differential & gearbox dismantling?

- where can I get internal differential/gearbox parts from?

Thanks,

Scott

I have similar symptoms on an 8P box, but instead it just whines at 25-35mph (independant of gear).

I've yet to do thorough trouble-shooting though...

This bearing, I take it it's inside the box itself?

Also the clutch release bearing, is this turning when driving or only when the clutch is depressed?

Cheers

Usually signs that the gearbox is on its way out to much of a common problem with Polo, iv just had a new gearbox from the same proplem it got so bad it sounded like i was running a charger lol

So can anyone recommend any online diagams of the inside of a 99 1.4 petrol polo gearbox? And how about any good places to get the differential/gearbox bits from?

(_subtle bump_)

http://www.volkswagenspares.com/page.php?page=Gearboxes

scroll down, its near the bottom

Here is a pic of an open 085 type gearbox.

You can see one of the diff bearings on the top, the other is on the opposite side out of sight. That particular bearing was really badly worn, unevenly scoured the diff housing where it is mounted and slightly melted that white plastic speedo drive cog next to it.

Thanks Nick_S and smiffyraf1!

I'm going to take loads of pictures as I take it to bits so I can remember how to put it back together again!

I haven't really looked at it yet (I needed a couple of days to calm down after it wasn't the clutch release bearing), but is there only one place to split the gearbox open?

Oh, one more thing, when I put the car back together what kind of grease do I need for the drive shaft on the transmission end, and how much do I use?

here's my guide on replacing the diff bearings:

http://www.polog40.co.uk/forum/index.php/topic,248.0.html

I'd buy the parts from VW to make sure you are proper OE quality parts, a set of bearings and oil seals should set you back about £50. Since you'll be replacing a bearing on the same diff and putting it into the same box you'll get away without replacing the pre-load washer. Bearings from places like GSF can be varying quality as they just buy from loads of different suppliers. You want to make sure you use the best quality, most long-lasting bearings you can, you don't want to be doing this job every year!

If it is the bearing on the end of the output shaft as BrownyG40 suggests (although how he can be so sure of himself without even seeing the gearbox in question is beyond me) then the process is fairly similar, you'll need a gear/bearing puller to remove that bearing though.

I'd agree that it's not the release bearing though because that would be engine speed related rather than wheel speed and would normally change as you press and release the clutch.

Thanks Hayesey!

That's exactly the kind of information I was looking for. No amount of googling would ever have got me anything like as useful. I'll post a reply when I see what's inside the box.

What's the consensus on replacing both differential bearings now that I've got this far? I haven't got a bearing puller but might be willing to invest in one...

sorry to say, but my polo was making similar noises, until it started grinding really loudly, then wouldnt go into first, then finally decided to spring a nice oil leak onto the cat, creating a white plume of smoke. now its sat in my garage, waiting for the replacement box to be fitted tuesday. totally knackard. if replacing said bearings doesnt do the trick, id run it to the ground, ring the aa to take you home, and get either a re-con box, or one from the scrappers.

Okay, so I've got the gearbox apart!

The first interesting thing was that when I removed the drive flanges, on both sides the remains of a small metal ring fell out. Are these the oil seals?!?

Secondly, a number of the bearings felt a bit gritty when I span them with my finger. The bearings on each side of the differential and the one on the rod nearest to the differential. The one on the clutch spindle seemed pretty smooth.

I haven't tried removing all the rods and cogs as I reckon I'll never get them back in again! But then again, there aren't that many bits so how hard can it be? I could get the whole lot out and clean it all up before I put it back together again...

What do you all recommend I do next? The gearbox casing and all the cogs look fine, it's just the bearings that are a bit gritty. If I replace them what kind of bearing puller do I need to get and what bits do I need to ask for from my VW dealer?

Where on earth can I get some proper diagrams for all this? I've got the VW Polo Haynes manual but it stops with the removal of the gearbox. Can I get a more specific one?

Thanks!

Those brass coloured things are called tapered rings and hence the name, yours are definately foobard! They are found on the later 085 type gearboxes, along with large springs for the flanges which the early 085 boxes don't have.

If the bearings feel gritty to spin, then again they are worn out.

You may as well get a quote from a local transmission refurbers. That way you can get the whole lot serviced for peace of of mind, if you plan on keeping the car a long time!

If you are going to do this yourself then I'd try and avoid removing all the gears if possible! It's a right ball ache to get it all back in right.

Like Nick said I'd be tempted to take it to a local gearbox rebuilders and get them to replace all the bearings. There are two more bearings on the other ends of the shafts which could also be worn, you can't see these without removing the shafts from the box though.

I agree as the output shaft bearing has to be shimmed and the bearing is easley fooked