I have an early TD5 90, bought really for fun and to let my boys learn some mechanical skills. So far replaced the hinges, swivel hubs, front dampers and springs and UJs trying to clear the advisories from the MOT.
The annoying persistent noise is on coasting to a stop with a fairly heavy sounding clunk which varies with engine speed.
Nothing when the engine is driving, tried slipping the hi/lo to neutral and still there. Presume the wheels are driving the gears rather than the normal and that is showing up some wear, Sounds to be around the transfer box but some guidance as to next move would be good.
sorry if this is the wrong place for this
Thanks Tony

Chock it, handbrake off, jack up one side and rotate wheels/ props, see if you can replicate the noise.
Hopefully its not the gearbox output splines but it is easy to check.
A Google search will bring up vids etc.
This is the introduce yourself bit, post in the 90/110 bit for more help?
Oh, and welcome!

Check the diffs, same method as above with only one wheel of the ground at a time.
You'll need the hand brake off and gear i neutral with difflock off, so make sure the wheels are chocked.

May also be worth checking your half shafts as well (the rears are straight forward to get off, just undo the drive flange bolts and pull)

When you did the UJs, did you check the prop splines for wear/play?

run it in diff lock with one of the props off in turn first front then rear

Hello and Welcome

I had a similar problem and it turned out to be my handbrake shoes catching when the prop stopped