1994 e420

So i fell into my desires and swapped out the 2.24 differential for a 2.82 from an s-class.

Took it for a spin and ....DAMN...much quicker....then...

This morning after driving for about 25 miles, the transmission starts shifting funny, the ABS light turns on and then the tranny does not shift from 2-3 or even 3-4 (even at really low throttle).

is it the differential? (the speedometer is off with the actual speed of the car, I have to find something to adjust..suggestions?...I am thinking this is why the ABS light is on)

It shifts fine when cold or if driving short distances.

The transmission was working fine before the swap.

I used 80w-90 gear oil in the diff.

Any suggestions and help are dearly appreciated.

Thanks in advance.