E70 X5 Rear Differential failure

[JCL]

Originally Posted by bawareca

How could I define that?My 87 325is race car diff is still going on with 440whp/400wtq and 255 slick tires.On the other hand I heard for a 4 E70 diff failures last week alone.My friend's 08 4.8i has the diff removed yesterday and the shop owners says that one of the bearing races has moved somehow and there is a complete mess inside.Likely nothing is reusable.

Any potential causal factors?

Tire pressures balanced left/right?
Tire sizes original spec?
Fluids changed out of spec?
Any tire spinning, even on-road (snow or ice)?

There are some web reports (very sparse) of E70 differential failures, but given that in thousands of threads here it has never come up, I would be looking to common factors in those failures. Driver abuse would be the first thing I would look to, unless there was evidence of poor maintenance. If it was a design fault I would expect many more failures than have been reported, and much earlier in the vehicle's life.