No drive

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Originally Posted by wayneg

I was discussing your no drive issue with PeterJam earlier and he seems to think if you have completely disengaged a front CV by it or the axle shaft breaking you could lose all drive. I am not clever enough to grasp it however Peter is very clued up on these things. With that in mind If I were you I would deal with the front CV first and see the result.
Get a cv from the UK if you need one. My last one was something silly like 25 pounds plus shipping.

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Thanks Wayne, I'm taking the night off from working on the car but will start the dismantling tomorrow after I get home from work. A scary thought though if you are traveling alone and break a front axle or destroy CV joint! I would have thought the VC would have transferred the drive to the rear! I will be taking it one step at a time to see what has broken. It sounded a bit like a large branch breaking off a tree when it went, enough that a couple of observers outside of the car presumed I had hit something below the mud (if only).

I had a look at your post re changing your CV's, I don't like the look of getting that big nut off as I don't have access to a 3/4" rattle gun. But that's a job for tomorrow ;)

Gary

There is a centre dif in the transfer box, the viscous is to the front of the dif. If there is no resistance from the front the dif wont transfer power to the rear and just turn the front, as open difs send power to the end of least resistance.
That is how Peter explained it or how my brain comprehended the lesson.
see page 576 of rave

A long quality breaker bar with a length of tube to extend it should give you enough leverage.

Yeh, that's right Wayne, in a diff the planetary gears will carry the rotation the the side of the diff with the least torque load.
The borgwarners viscous coupling is supposed to make the front and rear output shafts rotate at the same speed, but it takes a little while to heat up the silicon jelly inside the viscous unit before it'll lock.

The rear output shaft extends through the centre of the diff, and into the viscous unit. Thus it's still a conventional differentail (50:50), with a limited slip viscous unit.

A quick update...after finally undoing the large retaining nut (with a 1.6m extension on the 1/2" socket) there was good news and some not so good news. First the good news, it looks at this stage that the diff is fine. Bad news is that both the CVJ as well as the axle are stuffed. The axle looks like it snapped off at inside the CVJ after that there was no recovery. Now it's time to go sourcing replacement parts, Linrover look like they are getting a call tomorrow, they have a used axle shaft with CVJ for a bit over $100. All going well I may even be back on the road tomorrow :D.

Gary

Attachment 66100

Quote:

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Originally Posted by wayneg

There is a centre dif in the transfer box, the viscous is to the front of the dif. If there is no resistance from the front the dif wont transfer power to the rear and just turn the front, as open difs send power to the end of least resistance.
That is how Peter explained it or how my brain comprehended the lesson.
see page 576 of rave

A long quality breaker bar with a length of tube to extend it should give you enough leverage.

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I must admit I had never considered a front end drive failure and its consequences for loss of drive......completely!
It would take a fair amount of stress/wear to destroy the front end....I should imagine, what where you doing when it let go?
No diff is as strong in reverse as it is in the usual direction....unless it is pegged.
25 years ago I had a 2a, being silly I used to try and get as far as I could in 2 wheel drive.......this would fairly regularly result in a broken rear axel, I always drove around as a front wheel drive for a while after this happened.
Seems we cant do that with the P38, or it may be OK if we have a rear drive failure.
I guess if we had to get out of trouble we could apply pressure to the front prop shaft with a rope/ratchet strap and trick the VC into sending the drive/some drive, to the rear axle?

Didn't Lucky8 remove the front driveshaft and prove that the VC still sends drive to the rear? There was a YouTube vid of it I'm sure!

If your VC is stuffed, wouldnt you be getting drive to both ends regardless of failure of either axle?
If your VC is functioning as normal, possibly you will loose drive in the event of an axle failure.

Like me at first, you are missing the point that there is a central differential in the transfer box. The viscous coupling is to the front. If there is no resistance from the front the central diff will just keep sending all the drive to the front, as in any open diff. I would love to be proved wrong as this seems to be a bad revelation

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Originally Posted by Keithy P38

Didn't Lucky8 remove the front driveshaft and prove that the VC still sends drive to the rear? There was a YouTube vid of it I'm sure!

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Keithy, there was a Lucky8 youtube vid for sure, running the Rangie in rear wheel drive only, but that was only after they had locked up the VC. The did look like they were having fun on the ice though :D

Gary

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Originally Posted by wayneg

Like me at first, you are missing the point that there is a central differential in the transfer box. The viscous coupling is to the front. If there is no resistance from the front the central diff will just keep sending all the drive to the front, as in any open diff. I would love to be proved wrong as this seems to be a bad revelation

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We should find out tonight one way or another. I have just picked up the CVJ and shaft from Linnrover. Tonight all being well should see it fitted and tested. One part of me hopes it does not solve the problem as this is a rather disconcerting revelation should you happen to break an axle/CVJ out in the bush, but I am along Wayne's thought, the central VC diff is sending the power to the point of least resistance.....the broken axle. The other part of me hopes it will be fixed so that the job is completed.
I'll post the results as soon as I've got it fitted.

Gary