So, the darn thing is pretty much stuck and almost rounded out. Any ideas as to what next? Need to break torque, don't know if the RTV is sealed to the nut, and perhaps a replacement bolt. Any thoughts?

 

not sure which bolt,but RTV wont harden so its locktite, rust, cross threaded, over tightened.two things that ,help heat or tapping with hammer & punch,if its a nut you can weaken with die grinder etc. & chisel off.

 

Should have been more clear- this is the bolt that is a 5/16 or 8 mm allen wrench on the front cover. The rest are 9/16 and took quite a bit of convincing before they let loose. This is the last one, right next to the axle u bolts.

 

https://www.ford-trucks.com/forums/1...llen-head.html

 

No welder or other fancy tools here so I just got to work. Got them all off with much swearing and a sore shoulder. They all had blue loctite on them and were spray painted to the differential cover. The 5/16" hex had a lot of "stuff" in the hex that also required a bit of work to get it all out.

The oil didn't look or smell that great, but the gears looked fine. The bolts were way over torqued and the loctite was a real bear.

Anyway, cleaned up and ready to go.

 

I do diffs, transfer case, and trans at the same time. Some don't change diff fluid and ford says you don't need to unless it leaks or has been submerged in water but I would do it regardless.

 

somebody probably over tightened with 3/8 air wrench,blue medium strength lock tight rarely causes problems.