What broke in my transfer...

[Lorin]

As some of you will know, my transfer box 'broke' back in April, handily whilst I was in Spain https://www.landcruiserclub.net/com...ansfer-or-torque-converter-has-let-go.145327/

What exactly broke in the transfer box has remained a mystery, with most bets on it being the centre diff. So, with help of Toby, a forensic dissection was performed, which revealed a surprise result....

The first surprise was actually that there was no visible metal parts/shavings in the transfer box. In fact, at first glance it didn't appear that anything was broken. However, once we removed the input shaft and gear, this is what we found:

 

[Chris]

Ooer. So now the big question is how - why?

 

[Roger]

Thats quite an achievement Lorin - my simple brain is running to resistance such as centre diff lock being engaged on tarmac causing wind up and spline failure? I dont have the VC, could they fail and cause locked 4wd?

 

[Lorin]

There was no suggestion in the transfer itself as to why. In fact, before we disassembled it, everything rotated lovely and smooth. There was certainly no resistance in the transfer itself and the CDL wasn't locked.

 

[frank rabbets]

That wheel should have been a press fit on to the shaft. It looks like it was incorrectly loose. If it was the correct press fit no amount of torque from the car would cause it to move and wear like that. I suppose years of abuse could do it. Is this a common failure?

 

[Lorin]

That wheel should have been a press fit on to the shaft. It looks like it was incorrectly loose. If it was the correct press fit no amount of torque from the car would cause it to move and wear like that. I suppose years of abuse could do it. Is this a common failure?

The assumption is that it was all original in there but there's no way of knowing if it had ever been apart before. Can't think why it would've though. I can't find any other examples of this happening across other forums, so I'd assume it can't be that common. Like you say, it is all press fit on that shaft and everything else was tight on it. Could've been a one-off defect in the metal or a small manufacturing fault I guess..... Seems unlikely it's due to 'abuse' as I would've thought it would be more common on the many trucks running larger tyres, rock crawling and generally having a much harder life etc...

 

[frank rabbets]

That's right Lorin and I was not thinking you had been abusing BTW.

Every 80 main box (4 lol) I've had apart has had one particular drive dog broken off and lying in the bottom of the box so all those wheels at least had been incorrectly ground with that one dog taking the strain which should have been taken by about 40 dogs.

I've come across another box I suspect has a bent input shaft.

In the 70's my friend bought a brand new mini and after 2 years it kept jumping out of 2nd gear. The splined adjuster inside the box was hitting the inside of the gearbox case and the gear was not going fully in to gear. This meant only the ends of the dogs were engaged and these sheared off.

 

[Dave2000]

Pretty much the same as mine Lorin, mine was moving (but not really loose) on the shaft but the centre diff had gone awry. The lack of metal in the oil made it even more intriguing. Yours, mine, and one or two others have been mentioned on other forums means this is something that can happen, not a common problem though.

Re the VC locking, yes they can seize and it gives the same feeling as driving with the CD engaged, the tyres squeal like hell when cornering as the transmission 'wound up', it also add a lot of 'load' on the CV's.

regards

Dave