Discovery 2 / LT230 Transfer Box Loud Clicking

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

whats the main gearbox output shaft to input gear on transfer box splines like?

The splines are fine, no evidence of excessive wear or damage, it also looks strainght when spinning. Thanks

if you remove sump ,you can feel if theres any play in intermediate gear ,as you were running with front prop off diff gears were spinning ,theses can be noisy through design and also wear in diff housing and cross shafts

I would be inclined to refurbish the front propshaft, reinstall and see how things are after that.

Thanks for the advice. I think you are right and with regard to the diff noise being excessive due to it being worked overtime with prop off. I have already ordered the parts to rebuild the prop shaft as my plan was to put it back together and recheck. Top advice, thanks guys.

Try looking at the diff lock lever to see if it has been running in diff lock, then the diff lock gears (small bevel-shaped gears in the transfer box). These often break teeth. I usually replace as a set (there are smaller ones running against larger size), as both sides are usually damaged and the new ones sometimes have different numbers of teeth - which doesn't matter when you change them as a set.

Here's a link. http://www.landroverresource.com/docs/LT230_Transfer_Box_Manual.pdf. Go to page 17 of 80. Look at bevel gears 15 & 17 (sun and planetary gears). Check the teeth condition. If chipped, they will click up hills and corners,. Also check condition of thrust washers etc (ie items 14-18) while you are at it. In LR110 & Defender 110 I have seen 15 & 17 with differing numbers of teeth, so count teeth if replacing one type, or replace as a set - which doesn't seem to have affected ours. Hope that helps (if you haven't sorted already!)