"Time for a swappin"

[85 oil burner]

Help !!!! Hi yall I well I am in some trouble,ya see my "SF"14 bolt rearend on my 85 GMC burb,with a oil burnin,6.2 diesel and a 700 r4,decided to strip the gears in that rear,and I need to get to business,I was thinkin about huntin down a tried and true "FF"14 bolt,sliding in a detroit locker,with 3.73 gears or a 3.42 preferrably to save a little diesel,along with some replacement h.d. springs to get her into the 10,000 lb. weight class,but before I go trusting strangers and blowin $$'s I want to glean from those wiser than I on how to do this and if its too much trouble or worth the time and effort,so any help for this michigan hillbilly would be highly appreciated thanx in advance yall !!!

 

[bucket]

A rear from a 3/4 is a bolt-in, while a rear from a 1 ton is not due to different perch spacing and shock mount locations. Finding a 3.73 geared FF from a 3/4 ton should be fairly easy, but look for a non locking rear so you can instal the Detroit in the open carrier.

 

[85 oil burner]

Appreciate the info bucket,thank ya kindly,I was junk yard doggin a while back,and I saw a single wheel "FF" out of a 97 gmc 3500 he put a 3.42 in it to pull campers and save diesel cuz it was a 6.5,but I believe that they did not make a detroit locker for the "ff" until later so I assume it to be a open diff.but most of the legwork has been done I just wanna swap it over directly,to main concerns are the leafs they be rusty and if he was pulling 5th wheels they gotta be worn I am looking to buy 5,000 lb per side leafs online,but I don't know if they will fit the later "FF",I am gonna do some more homework before I make my final answer.Thanx again and keep on truckin.