73 diff into a 40 ff rear axle (1 Viewer)

[73fj40lc]

I am looking at installing a 40 rear ff axle into my 73 FJ40. I have read the faq section and nothing is mentioned on if I can use my 73 semi float diff into the ff rear axle. My goal is to have OEM disk brakes on a ff rear axle with a locker. I have looked at doing the 80 series rear axle swap but it will take custom work to cut down the axle, and I don't know if I have thoses services available locally. I am also not crazy about having custom made axle shafts in case one breaks. I have also looked at going with a 70 series FF but I worry about getting parts for the 70 series axle. It is also hard to find a 70 ff rear with disk brakes. So I guess my overall questions are will the 73 diff fit into a 40 rear ff axle? If it were you what axle would you end up going with for what I want in the end?

 

[PhrogsPhorever]

I have a 70 series FF axle on my '76 and it fits fine. You'll have to reposition the spring perches a little, and the axle is a little bit wider than the one on your 40.

Parts are pretty easy, bearings and seals are interchangeable with some US spec axles. Poly Performance made me new axle shafts, and the 80 series locker diffs work awesome if you get some long spline sfafts made. With the disc rears, I think the calipers are the same as the 80 series, the rotors are not the same, and I think either 4skinner or FJC rotors will work in my poring thru threads. I can't remember.

I have the 70 series drum axle, and it's fine for stopping power.

 

[Josie'sLandCruiser]

Hi All:

Yes, the semi-floater rear axle third member will fit and work in the full-floater rear axle housing.

Good luck!

Alan

I am looking at installing a 40 rear ff axle into my 73 FJ40. I have read the faq section and nothing is mentioned on if I can use my 73 semi float diff into the ff rear axle. My goal is to have OEM disk brakes on a ff rear axle with a locker. I have looked at doing the 80 series rear axle swap but it will take custom work to cut down the axle, and I don't know if I have thoses services available locally. I am also not crazy about having custom made axle shafts in case one breaks. I have also looked at going with a 70 series FF but I worry about getting parts for the 70 series axle. It is also hard to find a 70 ff rear with disk brakes. So I guess my overall questions are will the 73 diff fit into a 40 rear ff axle? If it were you what axle would you end up going with for what I want in the end?

 

[bikersmurf]

X2

Bolted a 45 FF rear axle into my 40, no mods required. If you use the stock 45 drums you'll need an adjustable proportioning valve to keep the rear brakes from locking up all the time.

I've currently got a 3rd in the FF rear axle that I pulled from a 40 front axle.

I also added rear discs. The brackets are different for FF and SF axles.