Help? FZJ80 locking axle with 3.70 gears possible? (1 Viewer)

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I hate asking a dumb question here but here goes.

With BOSSKLLA being diesel, I absolutely need to stay with 3.7 gears. BUT I would love to have an E locking rear axle with full floating bearings and disc brakes.

I'm aware the 80 diff/ locker can be made to fit the 60 housing.

Can the 60 series 3.7 ring/pinion be transferred over to the E locking third member? Ive learned the hard way before, to never assume!
 
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I'm currently running about 2k rpm@ 70mph. 4.1 gears would kind of ruin that for me. I'm only interested in the rear 80 axle.
 
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down in a hole.
might just hold out for an fj60 ff and then cable lock it. the ring and pinion for the 60 diff likely are not correct for the 80 diff. I do not know if aftermarket 3.70 gears are available- for cheap. personally, the FF is worth far more to me than a locker. you could always drop an ARB into it...
 
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Guess I'm asking about the 80 axle because they are cheap. At least what i think is cheap, 250.

From everything i read the thirds bolt in place of each other, but i wonder if the 3.7 ring gear will be too large for the housing, or if the carrier of the locker is at a different offset that would make the swap not possible.

I learned recently the hard way that a gs460 diff is not compatible with gs300 diff ring and pinion due to the offset. So i know better than to assume.
 

NookShneer

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Elocked 80 third member will fit in your existing axle. You may be hard pressed to find someone who would be willing to just part the elocked third and not the whole axle or set for that matter. (Front 80 axles are a smaller than the 9.5" front rear 60 axles)

FZJ80 rear axles are FF and also wider than your existing 60 axle.

If you could get ahold of an elocked third, you still need to grind the 60 axle housing, replace 2 longer studs and change out your axles to a FF 60 series axles and then pull the R&P which would be 4.10 to swap in your 60 3.70's. Which is why it is more common that people swap the whole axle instead of just the third.

This has a great write-up about the process.

digitalferg: Toyota 80 Series Electric Locking Differentials Retrofit for an FJ60 Land Cruiser (or other 40, 50 or 60 or even 70 or 80 series)
 

cruisermatt

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Elocked 80 third member will fit in your existing axle. You may be hard pressed to find someone who would be willing to just part the elocked third and not the whole axle or set for that matter. (Front 80 axles are a smaller than the 9.5" front rear 60 axles)

FZJ80 rear axles are FF and also wider than your existing 60 axle.

If you could get ahold of an elocked third, you still need to grind the 60 axle housing, replace 2 longer studs and change out your axles to a FF 60 series axles and then pull the R&P which would be 4.10 to swap in your 60 3.70's. Which is why it is more common that people swap the whole axle instead of just the third.

This has a great write-up about the process.

digitalferg: Toyota 80 Series Electric Locking Differentials Retrofit for an FJ60 Land Cruiser (or other 40, 50 or 60 or even 70 or 80 series)

The 80 E-locker will not work in a 60 semi-float housing, it does in a 60 full-float housing though.

@crashmonk, there are no 3.70:1 gears available for the 80 E-locker, however you will have no interference issues installing your existing 60 3.70:1 diff into an 80 housing.
 

The Phoenician

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With your diesel turning at 2k to make 70mph I would not regear to 4.1, the diesel has more than enough torque for anything you will encounter while offroading.

Not exactly an apples to apples comparison, but I swapped out an 80 axle for my rear 60 axle and regeared it to 3.73 and added an ARB locker. I wanted the full floater and I wanted the disk brakes and I wanted to be able to go fast on the highway. So I traded my 4.1 thirds for 3.73s with someone on this forum. I've been very happy with it and the braking improved a LOT. If you go that route, you will also need to change out the brake cylinder to an 80.
 

LINUS

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I just saw this as a header in the 60 & I'm a 80 guy, so no clue how our axle widths or diff offsets play with your drivetrain (alot of guys use a 60 transfer case if they part-time their setup, so must be somewhat plug/play)

Diesel 80's came with a ~3.73 & ran into the FF generation ('93+ in USA)

@crashmonk -being close to the Canada border, you & I both see diesel 80's FS on CL in either whole or parting, so you might see what happens that route. Most the diesel 80's are RHD imports, but they are imported in quantity, not rare around here.
HTH.
 

cruisermatt

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(alot of guys use a 60 transfer case if they part-time their setup, so must be somewhat plug/play)

Diesel 80's came with a ~3.73 & ran into the FF generation ('93+ in USA)

Virtually nothing between 60’s and 80’s are plug and play besides 3FE’s and 9.5” diffs...

Are you certain about 3.70’s in 80’s?

@GLTHFJ60, when you had Toyota lockers with the 4BT what gears did you have?
 

RockDoc

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@GLTHFJ60, when you had Toyota lockers with the 4BT what gears did you have?

4.10 - I have his old rear elocker sitting in a bucket waiting to go in the 60 FF rear under my pig project.

A quick look on Cruiser Outfitters website shows gear install kits specific to the elocker diff, but no gears that are specifically for it. Same gears between open and elocker carriers?
 

cruisermatt

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4.10 - I have his old rear elocker sitting in a bucket waiting to go in the 60 FF rear under my pig project.

A quick look on Cruiser Outfitters website shows gear install kits specific to the elocker diff, but no gears that are specifically for it. Same gears between open and elocker carriers?

I'm almost completely positive the ring gears are different.
 

RockDoc

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That was my strong suspicion too before looking. I certainly don't know for sure one way or the other.
 
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Aww man, this doesn't make me feel terribly confident. I'm all about the cheap!
 

LINUS

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The gearsets between elockers & open are the same. That I know per Just Differentials when they did my 4.88's on my elocker 3rds & me converting my axle shells to e-locker version, adding all the other parts from a wrecked lockered 80.

I swapped the full elocker setup into my unlocked 80 some 6-8yrs back, the carriers are where the differences are esp the FR bolt pattern to axle flange. The rear bolt pattern matches but you need different length studs. The RR axle also takes a longer section of splines on the RS axle shaft, lets the dog gear that locks the rear slide in/out to lock/unlock.

@cruisermatt
The diesel 80's shipped with a 3.73 ratio per members in the 80 subsection who like outside the USA. Maybe a quick search there to confirm with one of them?

Bummer you guys can't swap axles more easily - but above is what I know of 80's just because that's my wheelhouse. I'm a 40 & 60 relative newb.
 
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I'd like to find a ring gear part number on a diesel 80 that came 3.7's and compare to my 3.7 part number. Ya never know...
 

LINUS

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@cruisermatt - I will add that for the rear ring gear, Mr T mysteriously decided to notch the 3rd member flange for ease of install on locker 3rds where unlocked flanges aren't notched. Buying a locker flange gasket shows the 'template' real clearly.

It's exactly clearanced ~1/4" top & bottom where you stab the ring gear portion past the axle flange. Some people do the notching when converting, some don't- I did.

That may be why you have some thoughts about ring gears being different?

I'll add while setting backlash & runout is nothing new to me, when I consulted @cruiserdan some years ago, he stated the smart money was to let JD's, Zuk, -whoever else- adjust the locker 3rds on gearset swaps.
Open diffs where you add a locker of whatever brand/flavor & different gears weren't near as picky, just the locker 3rds. HTH.

I simply went with his advice as he was/is one of the reigning "parts gurus" (retired) -of the 80 world, so his advice to me might as well be added pages in the FSM.

If he chimes in, maybe he'll clear any other questions/myths of 80 axles.
 

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