Aluminum in the Oil ?!?!?!?!?!?!?!

Remove the Tranny, and take it apart, you will find your problem.

The splines in the tranny are gone... Wrong axles can do that because they are too short, and out of alignment.

Looks like the car was maybe high-centered, or the suspension was unloaded all the way and the axle rubbed agains the bracket for a while...

Find a How to, on a engine Swap, and pull the motor and do it yourself.

It will save you a lot of headache down the road...