Need A833 advice

IMO; yur doing the right thing.
I would be chasing the problem too.
There is no way on God's green Earth , that I would just drive it; IMO that is insanity.
My record for dropping that trans, and the GVod behind it, and the dual 3" pipes, plus the shifter, etc., is;
are you ready for it?
Seventeen minutes on a drive on hoist, with air tools; I have witnesses .
Popping the loaded mainshaft out is about a minute more.

BTW
popping the struts back in, not knowing if the anchor tab on the energizer spring is properly indexed, is a recipe for trouble, as the energizer spring is then free to rotate inside the hub. If that happens, the loss of one strut will cause shifting difficulties.

I just thought of a possible third reason for your trans to be malfunctioning. The M/S rear bearing is specific to this trans. It is not likely that any bearing store will keep stock on the shelf. It is special as to the center-hole, and as to it's depth.
But it is a bit of a PITA to install the retaining snap-ring. What-if the builder screwed up?
If the snap ring was not correctly fully installed, and eventually popped out, then the M/S bearing would be able to walk back and forth in it's bore.
As it happens, Chrysler made those gears helically cut, so then, the spinning input gear drives the M/S gears in one direction when going forward, and in the opposite direction when the wheels are doing the driving.
Hmmmmmmmmmmmmmm
It's just a thought........