Thirds from an 80

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The front 80 third is completely different and won't bolt up.

The rear depends on the year of 80. FJ80 had semi-float rear, the later FZJ80 was full-float. From what I understand, the full-float will work in the front of a 60-series, but requires different inner shafts (something about the splines, I think). No idea whether that means you can use the semi-float without mods.

A much easier option is FJ62 axles. The FJ60 had 3.70 diff gears from the factory, the FJ62 had 4.11 like the 80 series, and the 62 thirds should just bolt up.
 
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The front 80 third is completely different and won't bolt up.

The rear depends on the year of 80. FJ80 had semi-float rear, the later FZJ80 was full-float. From what I understand, the full-float will work in the front of a 60-series, but requires different inner shafts (something about the splines, I think). No idea whether that means you can use the semi-float without mods.


aren't 60 and 62 thirds interchangeable front and rear? so if it'd work at all it'd work for both fr and rr?

I'm going through this same process now and looking for a definitive answer as well.

Can I put the correct year 80 series rear third into my 60 without new parts or mods?

I've searched this and it seems the consensus is split.


and yes I agree that a 62 third would be less brainwork but 80 thirds are being tossed out like candy now so I'd like to take advantage of that.
 
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My 80 SF axles had a different pinion flange bolt pattern than on a 60, and the pinion is coarse spline, compared to my 80 which is fine spline, so the flanges arent interchangable. Unless maybe this 60 3rd id out of a 40 series or something. Check the pinion flanges on the 60 first I guess.

Also the 60 series is 4.11 (37:9) versus the 80 4.10 (41:10) but this shouldnt make a difference.

although most 60`s were 3.7, except for the 62`s, and some of the diesel 80`s were a higher gear, which you may have.
 

RockDoc

I'll take Bruce Vilanch for the block.
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Putting a LOCKED FZJ80 rear in the front of a 60/62 requires a new inner axle on the long side to account for the movement of the locker mechanism. I would assume that a non-locked FZJ rear would go in the front with stock shafts, but maybe someone with better knowledge can confirm. I have no idea on the semi-floater rear FJ diff into the rear of a 60/62, but suspect it would be a straight swap. I believe as far as lockers and gear kits and such for the rear, the 62-80 split is transparent.
 
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Not trying to hijack the thread from the OP but...

I have the round pinion flange as my 60 is an '87.


From what I see here: Cruiser Outfitters

The 80 flange may be round also but may have a different bolt pattern. swapping the flange isn' an issue IMO.

What I'd like to verify for sure is whether or not a non-locker 80 will bolt up with at most a new pinion flange.

This would be for the rear only!
 
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aren't 60 and 62 thirds interchangeable front and rear? so if it'd work at all it'd work for both fr and rr?

Only internal difference between a front diff and a rear diff in a 60/62 is that the rear SF has a square block/spacer on the pinion shaft that keeps the c-clips and axles together. In the FF front you just leave the block off the pinion shaft as it's not needed. Same holds true for installing a SF third in a full float axle, just leave off the block.

Round flanges can always be drilled with a second pattern for a different driveshaft if you need to.

Tony
 

nuclearlemon

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both 60 amd 62 diffs are fine spline. the difference is that 60s are 3.7 standard with an option of 4.1 (or other ratios, but rare) and 62s are 4.1 standard other ratios being an option. as mentioned, there is a block in the front that is not in the rear. it can be easily switched between diffs.

fj80s or fzj80s are the same in the rear if the diff is unlocked. locked does have a longer spline on one shaft. the front is completely different.

as for driveshaft mount patterns, i can't remember what my 60 measured and the 60 axles under my pig have universal round flanges, but my locked 95 axle is roughly 2 1/2 x 2 3/4
 
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if you got an 87 60, then wouldnt you have a 62?

If the splines on yours are fine spline then I would think you should be able to swap them, the ones I have in 60 series axles are 4.11 gears, and must either be out of a 40 series, or made for a 40 series with 40 series flanges.

My bad.
 

GLTHFJ60

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The 80 series diffs are 4.11's with the same flange pattern as the late 60/62. The thirds bolt right into the housings. If you are installing an 80 diff into a SF 60 housing, make sure to get the SF 80 diff as it will come with the spacer block installed.

I have an 80 diff in the rear of my cruiser.
 
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The 80 series diffs are 4.11's with the same flange pattern as the late 60/62. The thirds bolt right into the housings. If you are installing an 80 diff into a SF 60 housing, make sure to get the SF 80 diff as it will come with the spacer block installed.

I have an 80 diff in the rear of my cruiser.

Thanks all for the clarification!

GTLH - thanks for writing it on the wall - sometimes I need that!

I'll check on the SF vs. FF from the donor and get ready for the swap!

is there a recommended service for these while swapping or just new fluids and OEM diff seal?
 
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I would just check the ring and pinion gears for signs of wear, also you might as well check your bearings too.

Its much easier to replace all the things you need now while you have the axle apart.
 

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