[Closed] Gearbox issues

Occams razer - the driveshafts are the likeliest option as they are the bit that has been disturbed recently

But they’ve just been replaced

If it didn't do it before they were replaced then I'd look at those first. Just because they're new doesn't mean they're right.

It did do it before, which is why they got replaced. It's possible I did it wrong, but the same symptoms from two sets?

I should have put that info in the OP. It's possible that the old and new ones are both bad though, if it's standard wear.

Also one more thing I tried. I jacked up the front and put it in gear, and listened to the gearbox with a screwdriver on the housing. Nothing but whispering gears. I then stopped one wheel so the diff was working, still nothing but whispering gears from the gearbox. Bit of a rumble from somewhere else though but hard to tell with the engine going.

Both joints on both sides?

I fitted two complete GKN driveshafts. They are probably refurbs, but the outer joints at least are clearly new because they felt tight out of the box.

There's one other weird thing. The shaft on the near side, the short one, wobbles at the inner joint end as the wheels turn. The old shaft also did this. It's possible that it's normal and due to the more extreme angle as the suspension is fully extended, but it didn't seem to lessen with a jack under the suspension. There's no evidence of wobble or vibration whilst driving, just the symptoms as described.

Worn driveshaft causes vibration/rumble under acceleration.

I suggest you adopt the Land Rover doctrine: "Continue driving the vehicle until the noise becomes unbearable for the operator. At this point, consider an overhaul."

Worn driveshaft causes vibration/rumble under acceleration.

Certainly feels more driveshafty to me, tbh.

I too would suspect the new driveshafts. This on a passat? Are they as crap as T5 ones are where it's the splines in the hub ends that fails, not the CVs?

Diffs on fwd cars usually have one failure mode - out backwards through the casing. You could try taking a look at the oil and checking if there's any swarf or filings in it. Gearbox otherwise ok?

suggest you adopt the Land Rover doctrine: “Continue driving the vehicle until the noise becomes unbearable for the operator. At this point, consider an overhaul.”

And with owners with that Attitude no wonder they have a bad rep for breaking down.

Gearbox / Diff oil levels need topped up?

Gearboxes are fixed - nothing changes when the car turns, unlike driveshafts/CV joints and possibly wheel bearings.

Gearboxes are fixed – nothing changes when the car turns.

Apart from the diff, which on a FWD car usually sloshes around in the same oil, in the same casing. We had a diff pinion break free on my brother's 205 many years ago, but that was running stupid power and he did drive it stupidly. The hole it made in the casing was quite amusing The lost weekend while we juggled a new one into the gallic heap in the smegging rain less so.

Oil is fine although I had just changed it. Wasn't sure Id done the procedure correctly when we had the noise so did it again as part of the driveshaft fix and it's now fine. It shifts really well (dsg automatic).

Was worried about DMF but there are none of the symptoms really.

Are they as crap as T5 ones are where it’s the splines in the hub ends that fails, not the CVs?

Don't think so but the hub has also been replaced.

It’s nothing simple like a balance weight hitting rod on full lock?

Wheel bearing or inner drive shaft bearing perhaps?

+1 for a possible wheel bearing

When I say I changed the hub, it included the wheel bearing. Fortunately on this car the whole hub and bearing assembly is one piece and bolts on and off. Beats struggling with pullers.

It’s nothing simple like a balance weight hitting rod on full lock?

Would certainly explain the noise, but it does it on medium lock too if you are accelerating. Plus there are no balance weights on the shafts. It's not a balancing issue either cos it's fine when driving at any speed in a straight or nearly straight line. And you can corner as sharply as you like as long as you don't accelerate even slightly. So roundabouts can be fine.

And the shaft wobbles when the car is on stands and the wheels are turning. Is this normal? It's just off centre.

Potentialy ARB drop link bush? or a lower rear wishbone bushing failed.
Acceleration under lock loads up the wishbones differntly to straightline accelaration.
Stuttering over uneven road surfaces can lead to 'failed driveshaft' symptons when its actualy something else

Drop link ball joint is a good idea. They weren't fully tightened after I did the shocks because the tiny torx bit stripped and I had to bodge.

And the shaft wobbles when the car is on stands and the wheels are turning. Is this normal? It’s just off centre

Does it really do this? Have you checked it with a DTI? It definitely shouldn't as it means at least one of the CVS is knackered: can you wobble it up and down by hand?

tiny torx bit stripped

FFR the meyle ones have flats on the back between the link and the ball joint & you can get a 17mm cone spanner in there, just, so you never need use the useless torx bit on the front. If you jubilee clip the cone spanner to the link, you can even get a windy on the nut without risking amputating your fingers.

Drop link ball joint is a good idea. They weren’t fully tightened after I did the shocks because the tiny torx bit stripped and I had to bodge.

Top tip i find is when ever stripping the front end for any reason , buy drop links. ~Ensures that the torx doesnt strip.

You can always return them 😀

Does it really do this? Have you checked it with a DTI?

Don't need a DTI, it's really obvious, and it's not the gearbox flange moving or the cup but the shaft in the cup. Deviation of the shaft is about 5mm or so.

If this isn't normal then it's clearly faulty so I should be able to get a swap from ECP. I'm worried about having to argue with them about it.

ECP aren't that bad for returns, just try and go when its quiet and you don't have to queue with the chavs (perhaps film it on yer phone?). Wait a few mins and get a second opinion on here, but IME I've never seen one do that unless it was dead.

Was there plenty of grease inside the CV joint itself? The clicking can be a sign of a dry joint, so its possible the grease just needs to be distributed throughout the joint.

I bought complete driveshafts so I haven't looked inside the joints. Assuming it's a refurb unit since there's a payment for returning my old one, it's possible only the outers and the boots were changed.

Rumble on hard acceleration and wobbling point to inner CV joint problem.

asked a mechanic mate of mine. His response was:

its &*^%ed or they have fitted the wrong size races on the velocity joint or the cup was to worn to take them. I have had issues with those the other way where they were so tight they blew up in 10 miles

Thanks HF.

Runout on the LH that I think is faulty is about 1.1mm. The RH that seems fine is about 0.25mm, measured with a DTI.

There's no apparent play in the inner joint when off the car on the LH shaft, although there is when it's fitted, but having removed it the outer joint is rough as hell and feels notchy in certain directions. I mean, it was tight when I fitted it but I assumed that we just cos it was new. But after 20 miles or so of driving it feels terrible.

Are you sure the new driveshafts are the correct length fully compressed? I had to send one back for junior's 205. There are so many variations for soe cars that even with the chassis number they send you the wrong one. I've had a number of drive shaft running vissibly out by around a mm (in fact only .5mm because what you measure is double the runout) with no vibration.

Driveshaft or a favourite when someone has fitted new shafts a not very tight hub but.

Are you sure the new driveshafts are the correct length fully compressed?

Well, this is a good shout. I did check the length as there are two parts listed and their lengths differ by 2mm. But these two were identical.

When I measured the runout it fluctuated 3 times per rev rather than 1. This means it's related to the sliding rollers I think, cos it's more at the gearbox end. The clicking is more than once per rev also.

ECP have agreed to replace no quibble, but it's not in stock so I won't know til Monday.

Hub bolt spec is 200nm and 180 degrees, the latter of which is more than I can do with my breaker bar and a 1m length of pipe, at least before I chicken out.

200nm and 180 degrees

That is such a VW thing to do. Brake calipers on the t5 are 180+45. Without extending my bar though the engine bay and out the other side, there's no way I can get a proper breaker on there.

Well, that's according to Haynes. It says for the 6 sided bolt, 200nm + 180 degrees and for the 12 sided bolt it's 70nm + 90 degrees (or something like that). I have a 6 sided Allen bolt..??

And why so different? The bolt's the same size just the head that's different?

Might be fine and coarse metric threads. They Like to use M12 and M14 fine pitch on a lot of the t5’s bits. Usually they’re triplesquare sockets though to avoid slippage.

I think @hot_fiat has it.

Got a new driveshaft from ECP eventually, went to fit it and it wouldn't go into the hub. Every other time I'd just slid it in (no s****ing). I thought somehow it was a slightly wrong size or something, so I struggle for a bit then realised I had the old hub still in the garage. On the bench I was able to get it in, it's just a very snug fit requiring some force. Back to the car, a little more persuasion got it in place. But it's MUCH tighter fit than any previous combination of old/new driveshaft and hub. And guess what - clicking seems to have gone.