Discovery 2 / LT230 Transfer Box Loud Clicking

[mikesmif]

Hi all,

Thanks for taking the time to read this. I need your help. For reference my car is a 2002 Land Rover Discovery TD5 Auto.

Have just completed a full service on my Disco TD5. When taking it for a test drive I noticed a loud clicking/clunking noise coming from the car. It was so loud I drove home immediately. Got underneath, checked everything and there was nothing obvious, loose or otherwise. So I took it for another drive. The noise seemed to come more-so when under load or when I take my foot off the accelerator with engine breaking. If I matched the engine speed to the driving speed the noise quietened.

I got the ramps out and removed the front prop-shaft. As I did there is lots of play in it. Needless to say I thought I had found the problem. But in the interest of thoroughness I started it up and put it into drive. The front prop flange started to spin and after a couple of seconds the noise was back. Although it was quieter this time it was certainly coming from the transfer box near to the rear output flange. I know it is not the rear shaft as the hand brake was engaged and rear prop still connected with wheels on the ground, it did not move.

At this I decided to investigate the transfer box. (Going back a little when I changed the oil I noticed some small flakes of metal on the drain magnet. Nothing serious just fine flakes.) So I drained the box and once again small fine metal flakes on the magnet. I removed the box opened it up and completely dismantled it.

When looking inside all of the gears are in great condition, there does not appear to be any play in any of the inner race bearings. In fact nothing appeared to be faulty at all, there was not even any evidence of where the flakes of metal had come from. The only bearings I have not checked were the two output shaft final bearings, just inside the oil seals. (These have to be removed to inspect.)

So my question is this. Has anyone experienced this before on a Discovery 2 or LT230 T/Box? Is this likely to be related to bearings ect? Any Ideas at all?

Thanks again for taking the time, I know I have gone on a little.

Regards

Mikesmif

[BogMonster]

What sort of frequency one per prop revolution or very fast or ?

[mikesmif]

I would say roughly once per revolution. Thanks

[kiwi_110]

With the back wheels on the hard, and the front prop off, the centre diff is getting a work-out. The side gears are working to transfer all the power to the front flange. Could be that the clicking is due to damage inside the centre differential, perhaps a broken cross shaft or missing teeth. Unless you dissassembled the differential carrier itself, you would not know.

Does your model have a centre differential lock? If it does, try a short drive (on gravel or loose surface preferably) with the diff lock engaged and see if the clicking stops. Locking the diff stops all differential action through the side gears in the internals of the diff and the front and rear outputs then rotate as one. If the clicking is not evident with the diff locked, I suspect the issue is almost certainly internal to the centre differential unit.

Ray.