Autobox Clunk

Hi

Any ideas where to start. I have a 91 RR 3.9 with the ZF box. It is fine going fowards and kick down etc all works fine, but randomly when you select reverse you get a sickening metalick thunk and the whole vehicle moves slightly. It rarely happens when cold, but if the machine has been out on a long run it will do it 3 times out of 5 roughly.

Obviously this is not good but any ideas where to start. The oil is fine on the dip stick, and was checked by my "mechanic" at my last service.

Any guidance would be greatly appreciated....already been an expensive month getting it through the dreaded MOT!

Many thanks

Matt

Saw a post on another site suggesting cleaning the filter on the box. This is supposed to make a marked difference.

This is the thread: http://forums.mud-club.com/viewtopic.php?t=3427&highlight=gearbox

Hi,

Sounds like the chain in the transfer box. They do have a tendancy of getting rather slack. I had it on my old classic, in the end changed the transfer box.

Bryan