The rear pinion of my 1998 T100 (VCK21L-CRSSKA) mounts in the third member housing and isn’t removable without first removing the entire third member and then also removing the differential assembly from the third member. What rear axle is that?
Depends. Assuming you're just replacing the flange and utilizing the existing bearings and crush sleeve? If so, than I'd recommend taking out your pinion housing, measure pre-load (in-lb torque) as it is, pull old flange off, install new flange, and start tightening down the new flange. When getting tight, I'd then start checking your pre-load with the goal to get it just barely above where the original preload was. This ensures everything is tight. WFO guys know what they are doing though and clearly deal with this everyday.