Axle strength

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rcmccars

rcmccars

10 Year
Joined
Feb 15, 2011
Threads
22
Messages
259
Location
yucaipa, ca
I have an 86 fj60 with 80 axles. my front came out of a 91 and i put in longfield cromos, an aussy locker, and 60 hubs. my rear is out of a 96 and is stock with an e-locker. i am running 37-12.50-17km2's. my next plan is a v8 2007-2008 6.2l 6l80e trans. i havent decided on a t-case yet im looking at the atlas 4spd. i know the rear wont hold up with the e-locker and if i go with the atlas ill need a center diff. im thinking 14 bolt chevy. my question is will the front hold up to 400hp, low gears, and big tires? i think i know the answer but what do the experts think.
thanks matt

ps: i know everyone loves pics even if its a 60
IMG_0829.webp
 
With all that power and gearing and tires you're getting into the realm of having to choose what will break.

Something to consider with the Chevy axle - right now you have a high-pinion with the added clearance it offers. You would be loosing that wouldn't you?

Elocker or no elocker - I don't think it makes any difference in strength of the full floating rear FZJ80 axle. I understand that it -can- make a difference in how hard it is to get the bits back out of the housing if/when they break.

In building things up to be that tough - you might consider putting a fuse in the system somewhere so that you can choose what breaks. I saw an article a few years back about a product to splice into the middle of a drive shaft that would purposely break at a specific torque point - without dropping the shaft. Then it was a quick-repair to fix/replace the broken link. Something to consider?
 
I would think the front would not hold up to well. The front is only a 8" diff. With the cromos and birfs. The weak link would be maybe the ring and pinion. But, that's my assumption. You will have alot of reduction with the gearing.

Why not swap to a 9.5" front axle?
 
There was a guy on here from Australia who said they had an 80 series with stock axles running around 700-750hp (can't remember the exact number) without issue. Also, there are threads that talk about the elocker issue. I still have not heard of anyone running a standard, ARB equipped rear 80 series axle that has experienced a rear axle twisted at the splines inside the rear carrier.

I recall comments about the short splines on the elocker axle being suspect in those failures compared to the longer splines on the standard axles.
 
MaK92 4RnR said:
why not just go to a 9.5" toyota axle?
Click to expand...

80 Series: 8" third in the front larger birfs

60 series 9.5" third and smaller front birfs.

Better off making a hybrid, or buying another 80 rear e-locked third and welding on the outers of the front. You would probably need the new 80 high steer knuckles though. Might hold up with bobby longs spell of invincibility cast upon your inner/outer shafts. Though youd be better with an ARB if your going chromo shafts.

Or go the D60 or 14bolt route.

There is that new 69 third member out now too.
 
Buy a diamond 9.5" housing with 80 balls. You could use your Longfield Super birfs, inner axles, brakes, etc you would just need to swap the 3rd. Bobby said his 80's super birfs are good to 40" tires and as much power as you can throw at them. When I asked I was running them behind a supercharged V8.

Ryan
 
The reason I went with 80 axles was they where wider than 60 axles. The reason I don't want to go to tons is they are too wide. Its not too hard to have a 14 bolt housing shortened and get custom shafts made but I think the Dana 60 would be harder. I like the idea of the diamond in the front and reuse all my parts except for the third. I'll look into that. This is great stuff keep it coming
thanks matt
 
Just had a crazy thought...

Volvo portal axles

There is a thread around here of someone who put them on an 80 and they fit very nicely...

The bonus is they get a monster gear reduction at the wheel with huge ground clearance.
 
CreeperSleeper said:
The only issue with Volvo portals is they aren't much (if any) stronger than stock 80 axles.
Click to expand...

The axle shafts are about the same size - but they get a huge gear reduction right at the wheel - so they don't have to be stronger.

Of course if he's going to provide that much power and torque to the front end of the drive train... Volvo axles would be great for crawling, even without the 'more power'.

If he's mud-bog dragster racing though - better with power and strength.

So - what kind of application is the vehicle going to be applied to?
 
This is my dd and I live around rocks and light mud. SoCal. It needs to be able to get on the freeway that's why I want the 6sp trans. Get to the trail get me through and get me home.
 
Remember the XIV TTC IIRC there was a 4Runner with Volvo Portals that broke one rear ( actually was a front axle in the rear coz he was running rear steering ) that made the worst extraction ever from the tank trap ..

I trully beileve in Cruiser stuff .. 80 series rear with PP or Nitro rear FF Axles will be pretty strong .. and will safe bunch of ground clearance compared to any 14B ..

I only justify D60 and 14B ir you are going big .. I mean over 40" but that's me ..

I'm also agree with the hibrid idea . keeping the front 9.5 with 80 series knuckles ..
 
rcmccars said:
This is my dd and I live around rocks and light mud. SoCal. It needs to be able to get on the freeway that's why I want the 6sp trans. Get to the trail get me through and get me home.
Click to expand...

Ahh - so you're pretty happy with the clearance but need more power to run 80mph on the interstate and lower gearing off road.

On 37" tires - re-gear those 80 series axles to 5.29. That will help with the of-road gearing a lot. For the engine... Right now you have what? 150hp and 220ft-lb of torque? You could probably get what you need from 300hp and 350ft-lb of torque - maybe a 1FZ with a supercharger? I.e. is there a middle level where you would have 'enough' power and still not be blowing parts up?
 
I am happy with clearance. The reason for the motor change is to be able to get on the freeway and go up a grade with ease the other reasons are fuel economy and smog. Because I live in California I have to match the engine and trans out of a doner and (just so there is no problems guaranteed with the ref) out of the same vehicle type ie: suv. The 6.2 with a 6sp gives me power and about 15- 20mpg if I stay out of it. Keeping everything stock ensures longevity no smog issues and easly replaceable parts. I believe the 2f came with 120hp 20 years and 150k mi ago with working smog equip so I think 90 is giving it credit. I do still have 4.11 gears though. But I'm lucky to get 10mpg on the highway doing 60.
 
rcmccars said:
I am happy with clearance. The reason for the motor change is to be able to get on the freeway and go up a grade with ease the other reasons are fuel economy and smog. Because I live in California I have to match the engine and trans out of a doner and (just so there is no problems guaranteed with the ref) out of the same vehicle type ie: suv. The 6.2 with a 6sp gives me power and about 15- 20mpg if I stay out of it. Keeping everything stock ensures longevity no smog issues and easly replaceable parts. I believe the 2f came with 120hp 20 years and 150k mi ago with working smog equip so I think 90 is giving it credit. I do still have 4.11 gears though. But I'm lucky to get 10mpg on the highway doing 60.
Click to expand...

There have been several reports in the 80s section of people with larger diameter tires improving mileage by gearing down. I know it seems counter-intuitive, but it puts the RPMs up a bit higher and into the power band for the engine.

That said, your vehicle has the aerodynamics of two bricks being pushed sideways and is riding on gummy 12.5" wide 37" tall tires. The only way you have a dream in hell of hitting 20mpg is if you put in a diesel and get some hard & skinny tires - regardless of what engine and transmission you put in it.

Getting it up the hill or accelerating on the merge lane - for that you need to lower your gears down to turn those big tires. Good for control off road too.

For perspective:
A stock FZJ80 accelerates better and drives better on the highway than a 35" tire FZJ80 with a supercharger.
After re-gearing the 35" tire FZJ80 to 4.88 gears, it changes that game considerably.

I agree that your stock engine is underpowered - but between the engine and the axle gears, I'd say the larger bottleneck is the axle gears. If you were to re-gear to 5.29 it would put your RPMs back up a bit above what a stock tire set up would be. It should accelerate about like a stock FJ60 should - not great, but better. I don't see how you can put up with it as you're set up now... That has to be like driving a smart car.
 
Trust me in done putting up with it but instead of putting money into a 20 plus year old motor to get it to pass smog and still be underpowered seems like a waste of time to me. As for the gears that's part of this thread. I'm doing the engine swap but I need axles that can handle the power, gears, and tires. When I figure out what those are I can put in the gears I need but why waste money on gears for axles I don't even know will work. As for the mileage its only a guess right now but the motor has the capability to cut down to 4cyl when you don't need the power and it is very efficient so my hopes are high. the truck it came out of gets 12city 18 highway and thats from the EPA not the dealer. That's way better than my 8-10 and It has about 400hp stock.
 
back on topic

After some searching I thinking about diamond housings. The front would be basically the 80 axle I have now with a 60 third and I'm still thinking Aussie locker for the front its simple and cheap. The rear would be centered with a ford 9" third so I can get an Eaton e-locker in there. (it has a better track record than the Toyota) it will be a full floater with 80 outers and cromos. What dose everyone think of that setup.
Thanks matt
 
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