Had this same issue last year with the pinion gear contacting the carrier with a fellows 8-3/4 --- tranny shop could not figure it out ( they ruined his original case trying to make it work ) and it ended up with me to sort out --- gears were Doctor Diff brand 3.55 for 742 case --- what I did was remove .030 off the pinion face ,,, this does not compromise the gear or contact pattern at all --- no issues after that, gears set up ok ( with .095 shim ) with plenty of clearance for the carrier .
