E30 Zone

Trying to undo the fill plug, I cracked my medium case diff rear cover today.

The only option I had was to use a small case diff (same 3.91 ratio) that I had as a spare.

All the bolts seemed to line up and it's on OK. Except, on tightening everything up, the prop to input flange seems to pull the prop towards the diff. I measued the external dimensions and the carrier mounting holes to input flange seem to be the same on both diffs so it should be a straight swap. What am I missing? Has anyone swapped out a medium for small case diff and discovered something I have missed?

Small case diff is about half an inch shorter.

Slack off the big collar nut(I use a pair of waterpump pliers)on the prop close to the centre bearing,slide the rear of the prop onto the diff,do not forget to re-tighten the collar nut.

Be aware that a small case diff is not really suitable for the 2.5ltr engine.

I had a small case diff fail in France whilst on holiday last year with my 2.7 engined cabbie.

Thanks Daimlerman.

It always was a short term expedient just to get the car through its MOT today.
Having refurbed a complete spare rear beam and trailing arms setup, with all new bushes/footbrake and handbrake parts/ backing plates/ Slave cylinder seals, etc, I decided to have a go at the diff oil while the diff was out and completely smashed the rear cover trying to undo the fill plug. I had to get the car to the test station this morning and only had a small case diff to hand.

But, I failed to adjust the collar and the failing prop centre bearing sang to me on the way to the test station. I have ordered a new one from Cotswold to fit at the weekend ”“ ”˜til then, I have a newly MOT’d Touring with a fresh rear setup that I daren’t drive.