60/62 third member into my rear 80 locked axle

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davegonz

Keeping it Weird
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I'm currently contemplating getting new transfer case gears for my Cummins powered 80 to help get my RPMs down. My 80 has a 60 series split case and manually locking hubs up front. I'd like to try and run a third member from a 60/62 to see how my truck runs with 3.73 gears before I plunk down big money on Mark's gears.

So, my question is, can I easily swap in a front third member off of a 60 or 62 into my rear diff?
 
OK, 60 series third member.
 
I think there was some compatability issues when I tried to shove a 60 diff in my fj80.

Im trying to remember what the issue was, but it wouldnt go and I ended up buying a used 80 diff.

Maybe different output flange or it was a different pattern for the axle housing.

edit: Oh yeah, different pinion flange bolt pattern, and the pinion flanges werent interchangable as the 60 has a different pinion spline than the 80.
 
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I've used an 80 series rear diff in my '86 FJ60 (I'm running 4.11s in it) and it bolted into the diff with no problem. Driveshaft flange of late FJ60s, 62s, and 80s should be the same. I'm also using a FJ62 driveshaft for the rear shaft in a '97 FZJ80; identical flange pattern.

So if you're going to use a 3.70 geared diff from a 85-87 FJ60 you should encounter no problems.
 
Sweet. Now to find someone selling one for cheap :)
 

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