Rear Diff boiled over and grinding

Hi guys , I was driving on the motorway yesterday... on my way to Billing, when suddenly a grinding noise (and the smell of boiled EP90) started to come from the rear diff of my 1990 110CSW I stopped and EP90 was steaming out of the front end off the diff... where the bearing is. I've opened up the diff ad there is no obvious damage. Where should I look next? Could it be the bearing? Maybe a half shaft? The deeper internals of the diff?

I drove gently 20 meters yesterday and it made a grinding noise then stalled the engine. :doh:

yu might have several faults....
1) leaking oil at front - oil seal?
2) oil boiling - what was the oil level & why would it overheat - low oil or seizing bearings?

i would check for movement in bearing behind flange up/down rather than rotational ,ep90 will get smelly hot on long motorway journey,hence use of thinner oils in gearbox ,thinner transmits heat better and doesnt produce so much,turning gears through thick oil uses energy that energy becomes heat ,but i would be looking at brg and blocked breather maybe as well the front brg near flange is favourite

i suspect that if the front oil seal has gone, then it is probably the front bearing which is breaking down and allowing movement at the front of the shaft, therby wearing away the seal and allowing the oil to escape. Unfortunately it isnt easy to see the front bearing, from what I remember. as JM says - check play at the front flange.

As above, but start with the simple stuff

blocked breather could be an easy (and good) call!

If I was you I would get the diff out and have a good check round it. check the bearings and then whack it back in with some fresh oil.

you never know what oil was put in before hand.