bugger

heading along the A40 on the way to silverstone yesterday morning, doing a relaxed 50 along a flat then

BANG

both rear wheels locked up, thrown into the curb, bounced off and managed to keep it on the right side of the road (handy cus there was plenty of stuff going the other way). looking behind me as the smoke cleared i see me rear prop sat in the middle of the road, took me about 10 mins to find what was left of the coupling. the uj at the handbrake drum held ok though heh, the splined bit of the prop was still on the motor!

no warning, no vibe or clunking etc i was even under it few days ago and the coupling look fine. it should do i only fitted the thing 18 months ago.

i crapped me self

that sounds bloody scary, if you work out what caused to fail be sure to let us know, have you heard of this happening to anyone else?

That looks nasty. I don't think the coupling was the problem though. I would guess that the rear diff seized and the sudden load from the engine ripped the coupling apart. But then wouldn't the diff in the transfer box just transfer the drive to the front wheels?
Funnily enough, I've just come in for a cuppa while I take the rear diff out of my Disco.

diver said:

That looks nasty. I don't think the coupling was the problem though. I would guess that the rear diff seized and the sudden load from the engine ripped the coupling apart. But then wouldn't the diff in the transfer box just transfer the drive to the front wheels?
Funnily enough, I've just come in for a cuppa while I take the rear diff out of my Disco.

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Wonder if the diff lock is stuck on, and its that what caused the failure. I would imagine its towed back ok ruling out the rear diff.

Yeah managed to get it onto the verge in diff lock, no bad sounds from anything, just the slap slap slap of the half of the prop that's still attached hitting the underside

Went onto the AA low loader all right, no grinding or anything.

I'll have a proper look later on in the week and report back.

TheMunster said:

Yeah managed to get it onto the verge in diff lock, no bad sounds from anything, just the slap slap slap of the half of the prop that's still attached hitting the underside

Went onto the AA low loader all right, no grinding or anything.

I'll have a proper look later on in the week and report back.

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I fitted a new one to mine last year, "britpart" they said they have no problems with them, but I think I will have another look once the bastid weather gets better again.

The other thing that came to mind is the handbrake coming on or binding a bit causing it to overheat.

Blimey, glad yer OK to tell us about it! Wonder if it mighta even been a wheel bearing going - they can be pretty violent!

odenne said:

Blimey, glad yer OK to tell us about it! Wonder if it mighta even been a wheel bearing going - they can be pretty violent!

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My wife says she's gona get violent if I dunt get her car sortid this week, and I'd rather be strapped to that propshaft nakid than geet her angry.

She even has her own scratching post in the living room.

Well I had a look at it this afternoon. Good news is that the diff is ok.

Bad news is that the splines on the prop are totally shagged and my local indy dosen't seem to stock the disco rear prop.

bugger

Nasty, glad to hear you escaped. Looking at the way the rubber coupling has sheared around the bolts, it does seem as if something locked up. Especially as you were only cruising along with nominal torque being applied.

If either the diff or gearbox/trans box seized that would certainly explain the shearing of the coupling. Also you mentioned the splines being damaged, that also implies something locked up, otherwise why would they have stripped. I recommend you investigate as could happen again once it's all back together.

Is it an auto or manual ?

Did the engine seize/stall ?

Good luck

Nah the splines are knackered where the prop has obviously hit the ground with the internal splined bit in about an inch.

Diff moves ok both wheels turn ok without clunking or resistance etc

Engine was still running when I managed to stop!

TheMunster said:

Nah the splines are knackered where the prop has obviously hit the ground with the internal splined bit in about an inch.

Diff moves ok both wheels turn ok without clunking or resistance etc

Engine was still running when I managed to stop!

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OK cool, well it certainly seems a mystery. I know the last time I checked my coupling there were cracks in the rubber - your post has made me put this job at the top of the list now.

Good luck mate

Yeah defiantly worth checking.

As a update I drained the oil from the diff yesterday and there were more than a few 'bits' in the oil so your idea of the diff letting going causing it seems to be a good 'un.

Diff seems to turn OK like I said but obviously its buggered its self somehow even if it does still pass a basic function check.

I got a prop and diff off a breaker on fleabay for £100 and I'm gonna swap the diff out.

I guess I just gotta pull the halfshafts out a couple of inches then unbolt the diff etc?

I blew a diff last year and it locked up solid. It held the motor on about a 1 in 2, we had to drag it down the hill with the axle locked up to get it somewhere safe to look at it. In the process something else broke and it freed off again.
When we striped it virtually no teeth left on the crown wheel.
I can't see how the doughnut failing could cause the back wheels to seize up, so it's got be the result, not the cause. Diff has got to be favourite. If it was engine/gearbox it would have affected the front as well, so less likely.

Just finished taking the diff off - no fun in the rain I gotta say.

It looks ok until you turn the flange...turns a few degrees then locks and you need to really put some effort in to turn it further, the flange bearing is shagged and the teeth on the drive gear are very worn, makes a lot of crunching when you turn it.

On the other hand this diff I got of the bay for £80 is storming, all the teeth are spotless you can turn it with your little finger and its smooth as anything

Glad you've found the cause. Have you had a good look at the half shafts? It sounds as if they were put under tremendous load.

Yeah the halfshafts look good, splines are perfect and both are dead straight.

Just gotta get some gaskets on the way home tonight and hopefully I can get the new diff in this evening.

Good to see your safe! Now I know you did not have any vibes before failure so what the hell happened, any ideas yet?

A common problem on the tipper lorries (Daf) was that both diff lock lights would go out and yet they were still engaged. My brother in law was coming around the M25 when the transmission decided it had had enough of being wound up and the prop broke at the centre bearing pole vaulting 32 tons through the air!

So you were lucky.............if you know what I mean?

I know you know your car but is it possible the difflock bulb had failed?

I would (as no doubt would you) like some definitive reason for such a sudden failure.

regards

Dave

I'm fairly sure that the rear diff seized up, which blew the coupling. I'm confident the central diff is ok, it wasn't locked in or anything, the light works well it locks and unlocks quickly and the car drives in front wheel drive OK at the moment, no sounds or anything. Haven't driven too far...cus there's a big hole in me rear axle where the diff should be at the moment

I can't get replacement lock nuts for the diff anywhere, local hasn't got any and a machine shop down the road 'only does metric'...?

Pain in the arse! Hoped to get it done this weekend.

Oh and the MOT is due as of today...haha bloody thing

When my rear diff went it lost a couple of teeth on the crown wheel .. the size of bits left were large enoug to have locked up the gears if they had got into them, but I think they were also large enough that they dropped to the bottom of the diffpan and stayed there!! I guess you might have been unlucky, stripped a tooth or two and the bits lodged between pinion and crown wheel gears, or into the centre smaller gears and locked it up .. then fell out hence making it seem like it was free.
When we turned my diff, with the teeth missing, there was apparently nothing wrong, it only made noises under load.