Rear Axle Swap

highboy73 · Jan 20, 2004

customer has 78 3/4 1 wheel peeler that has seen to many miles.also has rear axle and springs from 85 extended cab 3/4 ton.I haven't seen the axle to take measurements cause it's a good drive from here but does anyone know if it will fit?
the old 60 had a 3.30 gear and the 85 rear has 4.10 i think that is why he mentioned it.
thanks

davids78bronco · Jan 20, 2004

Not sure if I follow here - a "customer" has a '78 3/4ton pickup, that originally, had a rear D60, but wants to swap it out for a rear D60 and springs, from an '85? And that's because the '85 has the 4.10 gears? At least, that how I read it. It'll be a direct swap out, but I can't recall if the pinion yokes are the same size. IF they aren't, don't go swapping them out w/o new crush sleeves, or anything else of that nature... but I'm sure you already knew that

highboy73 · Jan 20, 2004

sorry about the labeling of people.a gentleman came into my small repair shop and asked if i would swap the rearaxle from an 85 3/4 ton,which is not a dana 60 into his 78 2-wheel drive 3/4 ton. the 78 has a dana 60 with 3.30 gears and the 85 has 4.10 gears(not a dana 60)and he would also like to change the springs also.
the replacement axle is a good distance from me and i wanted to be sure if it would fit into his truck before i picked it up.

davids78bronco · Jan 20, 2004

If the '85s rear axle isn't a D60, then what is it? It's definitely not a 9", and I doubt it's a D70, or a Sterling 10.25" - IIRC, those weren't available until '86. Hmm, seems like some research is in order

highboy73 · Jan 20, 2004

i have no idea but i was told that it wasn't a dana 60?was there another rear available in that year?like i said i haven't seen it yet.
supposedly the lug nuts are alot bigger and the cover is differant.
i don't know alot about those 80's f-series except for the few that come in for repairs and most of them are 1/2 ton

davids78bronco · Jan 20, 2004

If the cover is different, then it might be a 10.25" Sterling. Whether or not it will completely swap in, I can't answer that - not without the same amount of online research that you could do anyway

highboy73 · Jan 20, 2004

then why did you answer my post?

davids78bronco · Jan 20, 2004

Because I have nothing better to do at the moment

highboy73 · Jan 20, 2004

you could of looked and seen about that rear axle
for the benefit of both of us

davids78bronco · Jan 20, 2004

Actually, I still am - trying to find out if the 10.25" and the D60 use the same size yokes, and what the spring perch measurements are

davids78bronco · Jan 20, 2004

Short answer is - yes, the '85 axle will fit the '78 - that much I did know. I've been trying to find out if they both use the same size axle yokes, and to find out if the '85s axle is a D60, or a D70. The 10.25" wasn't availble until '86, and had the VSS, to work with the EFI engine/computer. Ask your customer-person to check for casting numbers on the diff housing. That will answer 98% of your question... and should make it easy to find out if the Ujoints are the same for both axles.

highboy73 · Jan 21, 2004

i'm going to have it here thursday or friday,i'm not quite sure about the rear being a factory installed in the 85 just that is what i was told.I'm no genius just trying to get some info.the u joint for the 85 measures 3 7/8 across and the caps are 1 1/16
i had the driveshaft out of the truck here.