'89 Maverick DA noisy drivetrain

Hi Guys,

I have an '89 Maverick with a TB42S. On the highway when I am doing lower speeds in 5th gear, a clunk/grinding noise can be heard from somewhere along the drivetrain. It only does it when I am in 5th gear doing lower speeds or slowing down. Once I get the speed up a bit, it goes away.

Sounds like it's coming from towards the back so definitely not the front diff. Not sure if it's the gearbox, transfer case or rear diff etc. but sounds pretty bad and I feel sorry for whatever is slowly dying.

Any ideas?

Cheers

Possibilities.
clunk--- rear suspension bushes or
diff back lash.
grinding --gear box bearings or
diff and or axle bearings.
transfer case.
Try dropping out of gear at said speed and listen, rev engine listen, anything strange happening ?.