Rear axle crunch on full lock with CDL engaged

[Sirocco]

Evening guys.

Whilst trying to trace the origins of some drive line slack I thought I would take the 90 (1996 300tdi manual) up the road with the centre diff locked in high. It was fine until I tried to turn full lock to head back and there was a lot of crunching coming from the rear axle area.

The diffs were refurbished with Truetrac LSD centres about 60,000km ago. But I don't recall having issues like this with them. Does anyone else run Truetracs on their Defenders?

When the centre isn't locked there is a lot of play in the propshaft between resistance at the wheels to. This goes away when the centre diff is locked.

Rear Halfshafts are still original and the vehicle is near 145,000 miles.

Any thoughts?

G

[BilboBoggles]

It's not a good idea to do full lock turns on a hard surface with center lock engaged. The front and rear wheels have to travel different distances and the difference must be taken up by one wheel slipping. If it's a hard surface then one wheel will spin or you will twist an axle to death or something else will need to break to relieve the force that is built up. That noise you heard may have been just a wheel unloading on the hard surface, or an axle twisting, or your rear diff shagging itself. (A wheel unloading can sound quite nasty...)

Less play on the center diff when locked is normal. If there is a huge difference, then it may be the thrust washers in your center diff are worn, and a transfer case rebuild will fix that. Although it will go for a very long time like that. 145,000 is not a lot of k's but that depends on the flogging they have been getting.

[Sirocco]

It's not a good idea to do full lock turns on a hard surface with center lock engaged. The front and rear wheels have to travel different distances and the difference must be taken up by one wheel slipping. If it's a hard surface then one wheel will spin or you will twist an axle to death or something else will need to break to relieve the force that is built up. That noise you heard may have been just a wheel unloading on the hard surface, or an axle twisting, or your rear diff shagging itself. (A wheel unloading can sound quite nasty...)

Less play on the center diff when locked is normal. If there is a huge difference, then it may be the thrust washers in your center diff are worn, and a transfer case rebuild will fix that. Although it will go for a very long time like that. 145,000 is not a lot of k's but that depends on the flogging they have been getting.

thanks.

I know it isn't a good idea, I just don't remember it doing that ever before :o :D

It has done it on a gravel surface also, I have just never heard a Defender do that.

Hmmm, ok, back to the drawing board to search for my massive driveline clunk

Its' 145,000 miles, so about 225,000km?

There is a big difference in play between the front and rear prop when CDL isn't locked. Im thinking something has gone in the rear. Even with newly build diffs

G

[dullbird]

Can you take a video of the noise?

Might make it easier for people to help you diagnose the sound