05 chevy avalanche tranny issues

So first issue was the rear u joint broke.
Drove great for a day or 2 Then the diff.
When the diff went. Went into all gears .just
when moveing made alot of popping and
medal grinding and was making the truck
jump. Took the truck in to get the diff fixed
after it was fixed went to pick it up and now
it wont go into the (drive) but P.R.321 WORK
but is making a grinding noise or a plate
spin screach sound. And its sound like the
diff. But the place.is saying its the tranny
and the sound is echoing to the diff... Fluid
is good. But when i try to put in drive its like
is not there. Cant even feel with the shifter