I have an - 8" center differential that a PO put a SPOOL in, it has 3.80 :1 Ford gears. I'm swapping in a Posi center carrier unit . Pinion is not being removed - Only carrier is swapping not gear set, ring gear is re-installed on new carrier. Only carrier bearings should need attention ... use loctite on ring bolts- ? ... been to U-Tube - any experienced tips appreciated have fun .. 3.80:1 matches up nicely with the T5-Z Overdrive ratio (1:.68) .
Yes, use Loctite. Evenly torque ring gear bolts. Check your backlash and gear pattern, adjust as necessary. Depending on your gear set it sometimes helps to mark the ring and pinion before disassembly and align them the same way when reinstalling.