And some days, the bear eats you

Not a good day yesterday for Freightliner.
Got towed back to the yard, 300 bucks.
New rear section coming today, 2500 bucks.
Lucky I could read the tag on this 700,000 mile rear.
Being an owner-operator is great; until it isn't.

 

fairly simple fix, he said.

I got new gear unit up on a transmission jack,
tipped it in with the jack tilt mechanism,
got top two LONGER studs started to align everything,
and struggled three hours to get the thing into housing???

Every time I tightened any bolt, in any sequence,
it tilted the unit out of being parallel and square
to the face of the housing??? WTF???

I would think if the unit is hanging from two studs
and you tightened two opposing bolts it would suck it in?
friend of mine said "try lifting on yoke with Jack to align?"
Yeah, sounds good. No way. I just came in the house.
Tomorrow is another day. Suggestions, anyone?

 

No jinx there, just as you said, it should be simple and straight forward.
Only thing I can come up with is the CNC operator guy machining the housing
forgot to put a 45 deg. chamfer on the dia. to drop into housing.
If it had a lead in or taper, it would drop right in.
as it is, I have it in place and can't tell.

Tomorrow, all the bolts come out, and just top studs in place.
Then the struggle resumes anew.

Again someone who has "been there, done that" can chime in.
What am I missing here?

 

I found two shiny spots on the diff. housing where it contacts the housing.
I'm pretty sure this is my interference here. Has to be dead straight to go in.

I was going to pull the bearings to clean everything out and air blow dry.
I got 8 cans of brake clean. Not sufficient?

(Thx, by the way.)
I've done car rears, and dually rears, but nothing this big.

 

Shiny spots are on curbside bearing mount,
there is a machined radius
matching a similar sized diameter in housing