4x4 prop shaft replacement. Golf/Bora 4motion?

[Lyonzo]

Folks, I have no idea bout this sort of thing and am looking for a brief lesson, so bear with me.

Basically, just got the car back from the dealer where it was in getting the coilpacks done and a free "health check". I returned to be told of a list of things, most minor, but the most pressing was that there is no 4wd prop shaft fitted.

This then leads me on to the fact that if this has been removed, what else has?! Does the prop shaft just go straight into the transfer box and rear diff? Is the transfer box part of the gear box? How does it all work? Can a rear diff stop working? This could explain removing the prop shaft?

I've managed to find one on eBay, but am wondering if one from a Bora or Mk4 Golf 4motion would fit as well?

Great start to 2013!

[Phil-E]

Bloody hell. How long have you had the car?

They must have also had to change the coding to stop warning lights etc.

That would have been pretty obvious to spot under the car.

The octavia shares the same platform as the golf so assume it would work.

Phil

[Lyonzo]

Since mid December. Bought it from a small dealer outside London, it wasn't advertised as a 4x4 model but I noticed the badge on the boot and checked the reg. I'm now wondering was that all part of the conspiracy!!

I appreciate it should be obvious, but like I say I wouldnt have known to look as I only know the very basics.

[Huskoda]

If the propshaft is missing, then I would believe it likely that the Haldex box is seized/ruined, probably why its been removed.

[Lyonzo]

Is the haldex box seperate to the gear box? If so, could it be removed and the original gear box still function?

[Huskoda]

The gearbox is on the front axle. The Haldex unit is on the rear and houses the rear differential. There is, I believe, a PTO from the gearbox that connects to the haldex via the propshaft. You can remove the link and the front drive should work exactly like a FWD. Infact I believe thats how haldex works most of the time anyway, with the propshaft mostly just idling up to the coupling in the haldex box.

[Lyonzo]

Thanks for that. Like I say, its all new to me.

Could a faulty rear diff/haldex remain in place and operate as a normal axle just if the prop shaft was removed?

[Huskoda]

If the rear diff is free to move, then yes, I imagine it would be fine and unnoticeable, other than any warning lights that could have been disabled. Other than the clever computer deciding when it does so, the haldex unit is pretty dumb and just connects a varying % of power coming in from the propshaft to the rear diff. Without the propshaft, its just running in 'everything is fine, no power needed' mode.

If I'm wrong anywhere in this, someone who knows more please correct me.

[Lyonzo]

I assume my first port of call should be get a prop shaft fitted, then see how the haldex and diff perform when they're brought to life?

Also need to see where I stand with regards the dealer!

[Huskoda]

I'd be very tempted to say get your money back as its potentially dangerous. It was removed for a reason and I can't think of any good ones. Its also possible thinking about it that the rear diff is seized too and both wheels just turn together. Also possible something in it might go pop on the motorway and lock the rear wheels up. Not saying its likely, just stuff going through my head

If nothing else you've potentially already got insurance problems as that's quite a modification, irrespective of what it was sold as.

[Lyonzo]

Fantastic!

I'm over in Belfast sadly and bought the car in London. I've contacted trading standards to see where I stand though.

[snow_muncher]

If the propshaft is missing, then I would believe it likely that the Haldex box is seized/ruined, probably why its been removed.

Most likey case, or prop itself broke and too pikey too fix

iirc the Octavia 4x4 has a specific propshaft - its a longer wheelbase length to a Golf, so the prop is a few cm longer

check via etka to make sure though

Its also possible thinking about it that the rear diff is seized too and both wheels just turn together.

Not that likely tbh

The rear transaxle diff is in a separate section of the casing and uses different oil to the haldex clutch

[Lyonzo]

Cheers.

I had a quick look under the car there (wish I knew what to look for before I bought it!) and the rear diff is still there anyway, as I can see the flange and wee male end poking out. Any way if determining if the diff is sound though, or if its buggered? Or is a prop shaft needed first.

[mannyo]

A diff is straight forward to check.

Chock front wheels, Jack both rear wheels so they are off the ground, and release handbrake . now rotate one wheel in either direction. The wheel on the other side should I believe rotate in the opposite direction. If someone holds the other wheel you should still be able to rotate yours.

That won't check the function of the Haldex, for that you'll need a propshaft in place and a slippery road.

[snow_muncher]

That won't check the function of the Haldex, for that you'll need a propshaft in place and a slippery road.

An all wheels off the groound type ramp will do the job more reliably tbh

The haldex clutch should clamp on total lack of front traction

ps

the fuse will more than likely have been pulled too

[Lyonzo]

Thanks folks, I very much appreciate all the input.

I'm calling at a mechanics on the way home here so I'll get it up on the ramp and test the diff. I'm hoping it still has the 4x4 gear box too. I assume I should see something similar to what I can at the diff, in the way of another flange and male end?

I spoke to the garage in Epping that did the last 4 or 5 services on the car and that has at least reassured me that on paper the car is as genuine as it seems. He knew the name of the 1 and only previous owner before I even said it, and told me that if anything at all was needed on the car through its life, it got it.

So now the best case scenario is that the prop shaft has somehow got damaged after it was traded in, and it was simply removed. A total long shot, but fingers crossed!

[Lyonzo]

The haldex clutch should clamp on total lack of front traction

Could you just explain that bit further for me?

[snow_muncher]

The haldex unit uses a computer controlled hydrolic clutch device to simulate and out-perform a mechanical central diff.

On command of the computer it will pump oil into the clutch thus engaging it, allowing power through to the rear mechanical tranaxle diff

Basically the computer only enages the clutch when it thinks the car is slipping, as setup by vw

When all wheels are off the ground the computer thinks major slippage going on

[Lyonzo]

Well, everything is in place anyway- diff, transfer box etc.

With all wheels off the ground 1 rear wheel rotated freely and the other didn't move. No LSD I assume? Then with the car both switched on and then the front wheels driving, turning one rear wheel turned the other in the same direction. Apparently there was more resistance then on the male end on the diff than there was when it could move freely with the car turned off.

Does that sound like the diff is ok then?!

Edited 8 January, 2013 by Lyonzo

[karlbar2k]

I have a spare propshaft available as mine is now running S3 gearbox, been off the car a while but still got grease on the union joint.

[snow_muncher]

No LSD I assume?

Nope

Not even Audi RS series get rear transaxle LSD's

You can upgrade

Does that sound like the diff is ok then?!

Probably - but without a prop you really won't know 100%

Has the dealer come back with a response yet - Are you thinking of trying to get a refund or get them to pay for an attempt at a fix ?

[Lyonzo]

Havent spoken to the original dealer yet. I phoned my solicitor this morning for some advice so have to phone the dealer here today- not looking forward to it!

The best outcome would probably be to get a contribution to the cost of repair, then just pocket it as compensation and sell the car as it is. Though depending how much (if any) money he gives, it may be worth my wile to stick a prop shaft in it and see what happens.

Is the haldex unit part of the diff?

Is there any way I can get a part number for the prop shaft, then compare it with part numbers of other VAG cars?

[Lyonzo]

I have a spare propshaft available as mine is now running S3 gearbox, been off the car a while but still got grease on the union joint.

I tried to send you a PM there, but it says you can't receive any new ones?

[Lyonzo]

snow_muncher, with regards to this other topic of mine;

http://www.briskoda.net/forums/topic/260252-4x4-downhill-hesitation/page__hl__+hesitation#entry3067864

do the 2 possibilites you described still apply or the scenarios would still occur with no prop shaft fitted? The reason I ask is I was accelerating down a steepish hill yesterday again and the same symptoms occured. Obviously though I'm now armed with the knowledge that the 4x4 isn't working, so do the cases you mentioned involve some sort of electronic wizardry being performed on the rear diff, which would happen regardless of there being any drive there? And if so, is this another confirmation or clue that perhaps the diff/haldex unit is at least functioning as it should?

[snow_muncher]

The ABS/EDL and ASR systems are indepedant of the 4x4 system, they work on the front end of the car

The way VW have setup the haldex unit up is to operate as a traction control system for the rear of the chassis - logic is to allow just enough torque sent to the rear to stop slip.

If this isn't working and slip still increasing the ABS/EDL and/or ASR systems will register this and kick in

The button marked 'ESP' on your dash will turn off the ASR and EDL systems - so probably best left on at mo

The best outcome would probably be to get a contribution to the cost of repair

You've been scammed - dealer should be offering to pay for everything or offer refund and collect car from you