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A broken diff that wasn't broken...

PostPosted: Sun, 30 Aug 2020 12:25 +0000
by xychix
The indident:
on a track I arrive towards a tarmac road. As this road is driven around 90km/h and I have bad visibility I pull lever from 4H to 2H and (without making sure tension is gone) turn at a decent speed and with a blow to the pedal onto the tarmac (let's say a 120 degree turn). I feel the steer pulling back and hear 3 decent 'bangs' (or snapping sound) drive my car on the other end off the road and rotate a bit in order to allow the tension off and get it in 2wd.

We drive 2km along the road and first next patch of grass I run some tests. in 2wd I have no issues no matter what I do.
in 4WD there is a clear ticking noise (3 per wheel turnover) but ONLY when turning.

I do not use the 4wd for the remainder of the holiday.

Diagnose:
we drive to a patch of sand and try and refind the ticking noise, nothing. I also do have the feeling that dispite the packed sand the steering wheel isn't pulling back that much. I had the feeling it wasn't always engaging in 4wd properly (but the dash light shows different...

Pulling pieces apart:
-removed both driveshafts they look good (dust cap on the outer joints is gone but i knew that. plenty of grease still in there. a bit dirty.
- removed and opened the diff, looks like new...
- opened up the ADD, sleeve moves freely

WTF, there was so much tension, there was clear bangs... something SHOULD be broken right!?!?!

what am I missing? sleeve in transfercase?

Re: A broken diff that wasn't broken...

PostPosted: Sun, 30 Aug 2020 12:26 +0000
by xychix
crap, @admins feel free to move this to drivetrain subtopic. My bad. apologies.

Re: A broken diff that wasn't broken...

PostPosted: Sun, 30 Aug 2020 8:39 +0000
by martynvella
My guess would be a damaged CV.
Only when turning is what I base my suspicions on.

Re: A broken diff that wasn't broken...

PostPosted: Sun, 30 Aug 2020 9:06 +0000
by Gipsy
And the tick tick tick, classic cv joint noise! If the boots are torn, even if there's grease in there it's likely that the balls and cage are damaged.

Re: A broken diff that wasn't broken...

PostPosted: Mon, 12 Oct 2020 2:06 +0000
by xychix
Gipsy wrote:And the tick tick tick, classic cv joint noise! If the boots are torn, even if there's grease in there it's likely that the balls and cage are damaged.



yep, something like that potentially.

removed CV's and diff. Flushed all. Did all bearings and seals on diff (which lokked quite good inside) and flushed and redid all grease caps (cv booth?) with new parts and grease.

So far no issues. Only issue is the cost I went trough and didn't identify the issue. This time I'll drive till it breaks

Re: A broken diff that wasn't broken...

PostPosted: Mon, 12 Oct 2020 5:06 +0000
by Gipsy
Dry balls and cage... Bit of grease and all good? If there's no issue maybe you fixed it :D

Re: A broken diff that wasn't broken...

PostPosted: Tue, 13 Oct 2020 5:39 +0000
by hiluxxury
3 clicks per wheel turnover sounds like a tripod to me - the inner CV. It may have popped out - do you have a suspension lift?

Re: A broken diff that wasn't broken...

PostPosted: Sat, 17 Oct 2020 12:01 +0000
by xychix
hiluxxury wrote:3 clicks per wheel turnover sounds like a tripod to me - the inner CV. It may have popped out - do you have a suspension lift?


2" lift, no diff drop.

Can it pop itself back in? cause when we took it all apart a few weeks later all looked good.

Re: A broken diff that wasn't broken...

PostPosted: Sat, 17 Oct 2020 5:41 +0000
by Gipsy
If the tick tick tick was with the steering turned its possible that the grease was not sufficient for the extreme of range, your attention to stripping and degreasing probably spread the grease to the extremes and solved the tick tick tick. It's possible the cv popped in again but dry cage and balls is most likely to be the case.