E30 Zone

got rumble from the diff (area) when slowing down,
louder rumble when slowing down from faster speeds,
looking to swap over a diff, but could it be a bearing or another external part,
just want to save a bit of time before i jump feet 1st into swapping diff,

(car is a 320I AUTO WITH LOW-ISH MILES)

cheers chaps

before swapping the diff, check the prop flexi guibo coupling and centre bearing. also the wheel bolts...

also, brake pad check? assuming the noise is when braking? or just downshifting?

the car has rear drums,
the guibo doughnut could be perished a bit as car hads been standing for a while, and check bearing between front a rear parts of the prop ?
or centre diff bearing ?

the centre bearing as a whole (the rubber mount / bearing that guides the prop) can fail causing the prop to flap about.
i've never seen a problem with the rear or centre joints in the prop itself, only the frunt guibo.

if you have rear drums, whip them off and check the shoes. the backplate may have rusted, letting the retaining pins drop through out and the shoes can then go wherever thay want, making a mess as they do so.

i presume its a prop diff thing,from the sound,
would rear brake shoes cause a rumble ?

they can make all sorts of noises
is it when braking? or lifting off/downshifting?

If it happens with engine braking, rather than when the brakes are applied, I'd be checking out the big rubber bush that supports the rear of the diff. If it's badly worn, there could be metal to metal contact when braking torque is applied to it.