Bearing advice please!

My Disco makes a whining noise when I'm driving (and I've not got a puppy stuck under the bonnet). It's a bearing, somewhere in the transmission. The whine seems to speed up with the wheel speed, not the engine speed, and the noise fades when coasting or going downhill. People have suggested either gearbox or transfer box, which sounds right, but is there any way of isolating it further so I know which is the likely culprit? I don't want to remove one to find it's the other!

Secondly, once I know which bearing it is, how difficult are they to replace? I'm OK with spanners, and have changed gearboxes in the past, but never dismantled one.....

download gearbox manual and look

Ta for the reply- been studying the manual, but it always looks simpler in a book! If you can shed any light on which bearing(s) it might be, I'd appreciate it. Guess otherwise I'll start ripping stuff apart and see what looks like it needs replacing....

Aint got a clue! Got an auto and a series not a manual disco


Only bearing names I can think of are layshaft and mainshaft but thems would be a bugger if it is cos thats a lot of effort

slide under it and jigel ya front prop if the ouput flange moves up and down then ya lucky its just that bearing and you may be able to just tighten up the flange but ya can change that bearing with the box still in the car. it could also be a uj on its way as these some time wine so check everything ya can see first if not its a case of pull both boxes and either strip um yer self or get a specialist to do it for ya cos they aint all that easy.

Thanks, good info, I'll check tonight

change the oils in g box and tranny box see if that helps first before ripping things out

Done that- the noise got worse
Thanks anyway