Outer Limits 4x4 Board

Hi Everyone,

I have a 1985 Hilux petrol and it has had a hard life,
I am looking for some advice as to what could be causing a knocking noise which is comming from the rear while driving.
The knocking is associated with the tires turing (it speeds up as I do)
Its not,
Brakes (adjusted properly now)
Wheel bearings (done those today)
The tires (changed those arround)

Does anyone know how I would check things like the diff or uni joint.
Is anyone has any advice/ideas they would be appreciated.
THanks,
p.s. this has been posted on other forumns.

Climb under the back, and check the unis/tailshaft for any excessive play. That would be an easy way to check.

another thing you can do is drain the oil from the diff, if it has lots of shiny bits of metal or chunks on the oil somethings fubar, you will probably need to then pull the diff centre out to look at what's damaged in the diff.

Check your UJs first

Climb under and give them a shake. Should be tight with stuff all movement and nil noises.

take the rear tail shaft of and engage 4x4 then take for a drive see if the noise is still there