Cleaning a diff prior to fitting

[Dominic]

Hi all

I'm fitting a 3.9 diff in the next few days. I bought it a few months ago, and have no idea how long it had been sitting around. It looks clean enough inside, but I have no way of knowing if bits of grit etc might have found their way inside. It turns smoothly with no roughness from bearings. Should I clean it out with paraffin or similar prior to fitting? Or should the oil when it's in situ flush it sufficiently?

[bmcecosse]

I suppose you should clean it - but if it looks ok, I would fit it - run it for a couple of hundred miles, and then change the oil.

[Dominic]

That was my preferred plan certainly - I considered re-using existing oil to flush out, then changing for the new stuff after a few hundred miles

[bmcecosse]

For all it costs - use new oil......

[JOWETTJAVELIN]

I used to use paraffin to clean things but went on to use petrol - it cleans better than paraffin and dries quickly as opposed to the greasy residue of paraffin.