Strange goings on when driving downhill under load

[MudRunnerTD]

I would put my money on Hubs too. Much more likely than a transfer case failure. There ain't much in a hub and a little front diff wind up and they will jump a tooth.

[PeeBee]

I can't see this happening with chains jumping cogs or gears jumping out of mesh, you would have serious issues and it would happen more often. I am thinking its transfer case wind up and its releasing as a reaction thru the wheels/suspension. I had a pinion bearing fail on a landcruiser and it went bang in an instant, however didn't manifest into a total failure until 200klm down the road. I would also revisit the pinion bearings for movement, however would think the gear set would be well and truelly gone by then, as mine was.

[Winnie]

I would put my money on Hubs too. Much more likely than a transfer case failure. There ain't much in a hub and a little front diff wind up and they will jump a tooth.

I have put a new set of hubs in it and it didn't make a difference. If it was a hub surely they would show some wear? I'll pull them off to confirm.

I can't see this happening with chains jumping cogs or gears jumping out of mesh, you would have serious issues and it would happen more often. I am thinking its transfer case wind up and its releasing as a reaction thru the wheels/suspension. I had a pinion bearing fail on a landcruiser and it went bang in an instant, however didn't manifest into a total failure until 200klm down the road. I would also revisit the pinion bearings for movement, however would think the gear set would be well and truelly gone by then, as mine was.

Yeah I've been thinking wind up, but why would this be happening? It has been hapenning for about 3 years randomly, I've done a lot of 4wding since and other than when it skips, it drives great.

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[PeeBee]

You don't need much difference in tyre diameter from wear to have this happen, and if you are crawling around on grippy surfaces the wind up will build and release on the next bit of slippery stuff. I used to get this climbing out of burgoynes with my tyres that had worn more on the rears than the fronts, didn't get the release bang when driving , but needed to reverse back and forth a few times and then sometimes it was a significant clunk as the transfer case was moved into 2wd. I would check the tread depth front to rear.

[mudski]

When you remove the hubs take a pic of the gear in the selector part in both lock and unlock positions.
The hubs you bought were new? Genuine? I have pics somewhere of the differences between oem and the Chinese hubs. The gears were noticeably different.


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[Winnie]

You don't need much difference in tyre diameter from wear to have this happen, and if you are crawling around on grippy surfaces the wind up will build and release on the next bit of slippery stuff. I used to get this climbing out of burgoynes with my tyres that had worn more on the rears than the fronts, didn't get the release bang when driving , but needed to reverse back and forth a few times and then sometimes it was a significant clunk as the transfer case was moved into 2wd. I would check the tread depth front to rear.

That would have made sense a couple of years ago as the tyres were definitely unevenly worn. But I have brand new tyres now and it hasn't made a difference.

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[mudski]

Found them.

Check out the teeth size differences between Chinese and OEM. No wonder the Chinese knock offs were jumping. The last pic you can see the wear on the teeth from it. So also make sure the outer gear is throwing in enough to properly mess with the gear in the axle. Which as said this can be adjusted if its not. Or you want to make hem throw that little bit more.

[Winnie]

Thanks Mudski, I didn't know they were adjustable.
I replaced the old ones with 2nd hand genuine.

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[mudski]

Thanks Mudski, I didn't know they were adjustable.
I replaced the old ones with 2nd hand genuine.

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Yeah those six ( i think there is ) pins that hold the gear in the hub, come out and then that gear winds out, its on a thread. So all you need to do is wind it out bit and put the pins back in. Your issue might be a simple as not enough throw in that gear to mesh with the other gear on the axle.