Back axle - thicker oil option?

[XJ_Driver]

Hi,

I have noticed a slight 'clonk' from the back axle on my XJR starting to develop when moving off from rest. I am thinking about changing the axle oil. I read on another post that Millers Transax 75/80 (or equivalent) is recommended, but would a slightly thicker oil (to counteract wear in the axle) be advisable? At one time I would have simply added a can of STP or similar, but may be that's a low tech approach to take these days?

[oldtimer]

What makes you think the clonk is coming from the Diff. There are plenty of other items that might well go clunk in the night. Sorry to say that a change of oil grade is highly unlikely to eliminate a clunk.

[XJ_Driver]

True enough, but this does sound like diff to me.

I put the same question to a mate who works in the tech department at Morris Lubricants, Shrewsbury this afternoon and he suggested using their XEP80w-90. I'm going to give that a go and see if it makes a difference.

If not I shall have to investigate further!

Thanks.