Need help identifying a part (again)

[jfalcon]

Tried to install the rear differential into my X5 (Vin:L098986) and the rear differential I was sold by my former mechanic is too small it appears. The axle splines do not click into place.

The one I pulled off had number of:
75230940 engs40015

The new one has number of:
026 23908
7553948
engs490-15

What is the difference and what do i order?

[jfalcon]

Or, is there a way I can make this differential work? It appears that rear differentials are getting harder to come by so...

[jfalcon]

So looking at the number of the differential that came off the car has it as a 3.64 gear ratio rear differential. This doesn't match what should be in here according to RealOEM which should be a 3.91 and possibly explains why the rear differential exploded.

Any ideas on how i can move forward with this?

[jfalcon]

Went under the car and here is the new differential that we're trying to figure out where it came from. Obviously it bolts up but wtf?

[jfalcon]

From the otherside...