FJ60 front axle in an FZJ80 or FJ60/80 hybrid axle? (1 Viewer)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Joined
Mar 8, 2010
Threads
30
Messages
605
Location
08087, NJ
I know this seems like an odd question... but I am looking at options for TALLER gears for my FZJ80, the reason being a potential diesel conversion in my future.

From what reasearch I've done, the 8"HP front diff in my 80 is the restricting factor for finding taller gears. The rear 9.5" is the same as the older cruiser stuff though, and I can use the 3.70 gears from the older cruisers in it.

If what I've stated above is true, can I have a hybrid acle built using FZJ80 front axle tubes with a 60 series diff housing? Would it be easier to mod the 60 axle complete to work with the 80 front suspension? If I had a spare 80 rear axle assembly, could I use the diff housing from the rear axle in the front to build my hybrid?

I know the other obvious issue is the steering... ideas there? Can the stock 80 steering box be retained and new knuckles/linkage be used?

This seems like a whole lot of work for taller gears, but I don't want to go as far as putting Danas in or something of that nature.
 
You could use a FJ60 housing with IFS hubs, which would give you a 61 or 62" WMS ( can't remember exactly ). Weld on the spring pads, radius arm brackets and panhard mount, then you're good to go.
 
Go with a Diamond axle or the like. Make it the exact same width as an 80 series with a 80 series rear pumpkin.

Diamond Axles - Front/Steering Axles

Thanks for the option, I just sent them a message.

would 3.9 gears ok? they are available ex factory

Really? Where can I source them? 3.90 isn't much taller than 4.10, but combined with a 35" rubber overdrive it might work out ok.

You could use a FJ60 housing with IFS hubs, which would give you a 61 or 62" WMS ( can't remember exactly ). Weld on the spring pads, radius arm brackets and panhard mount, then you're good to go.

This sounds like a relatively simple solution, definitely something I can handle on my own.



Can anyone verify that the 3.70 FJ60 gears can work with the FZJ80 E-locker differentials?



Thanks everyone for the help so far!
 
i think i have a mini-truck 3rd with 3.70 gear's in it if your interested, actually now that i think about it i've got some FJ60 3rd's with 3.70's laying around too
 
You could use a FJ60 housing with IFS hubs, which would give you a 61 or 62" WMS ( can't remember exactly ). Weld on the spring pads, radius arm brackets and panhard mount, then you're good to go.

I am building this same setup for my 4 Runner right now, but setup for leaf springs.

The only issue with this setup going into a FJ80 would be if there is enough room on the axle tubes to mount all of the FJ80 suspension brackets. The tubes are significantly shorter on the FJ60 housing than a FJ80 housing since you are making up your width with the IFS hubs and will still be narrower in the end than a stock FJ80 axle. Before going this route, double check that things will clear each other like the control arms and coil springs with the tires.
 
Really? Where can I source them? 3.90 isn't much taller than 4.10, but combined with a 35" rubber overdrive it might work out ok.


what diesel and transmission are you thinking of transplanting?

Aussie HDJ80s had 4.1 gearing std, this was changed to 4.3 for f the diesels in the HZJ105s

With 35" rubber, most guys over here lower diff ratios to 4.56 or 4.8 particularly on diesel models, as the bigger rubber really saps the torque.

I have 35" tyres on my HZJ105 with 4.1 ratios, and I find I am at least a gear lower than on standard rubber for any decent hill. Crawling is hard on the clutch with 4.1s in mine in steep terrain
 
what diesel and transmission are you thinking of transplanting?

Aussie HDJ80s had 4.1 gearing std, this was changed to 4.3 for f the diesels in the HZJ105s

With 35" rubber, most guys over here lower diff ratios to 4.56 or 4.8 particularly on diesel models, as the bigger rubber really saps the torque.

I have 35" tyres on my HZJ105 with 4.1 ratios, and I find I am at least a gear lower than on standard rubber for any decent hill. Crawling is hard on the clutch with 4.1s in mine in steep terrain

Right now I'm looking at 3 options... Isuzu 4HE1, Hino J05D, and Nissan FD46TA, all of which use AW450-43LE 4-speed automatic transmissions. The Hino and Nissan won't rev past 3k, the Isuzu will rev a little higher, but not much.

The Nissan motor is the most likely, since it seems to have the most clearance around the pan and oil filter, and it's starter isn't an issue like the Isuzu. It is also the cheapest option, as 99-04 UD trucks seem much cheaper than NPRs and 05+ Hino/UD 145s.

The Nissan motor makes 375lb-ft at 1600RPM, and 175HP at 2800. I would like my cruising RPM at 65MPH to be as close to 1600RPM as it can be.

Using an online gear ratio calculator, with 3.9 axle ratio, marks .92 OD gear in a split case, and 35" tires (the biggest I'd like to run) I'd be at 1612RPM at 65MPH.

If I run the 3.7 axle ratio and leave the TC alone, 35" tires, I'm at 1662RPM at 65MPH. This is honestly the option I'd want to take, since it will allow me to keep the full time 4WD.


I know the 1HD has a more broad operating RPM range than these engines, which is why I'm asking what my options are...
 
There were 3.73 ratios available in some markets for the 80 series front diff, and 3.70s for the 9.5" rear are common in earlier Cruisers.

These front gears are not that common, they are not found in North America, and are quite expensive.

I'd stick with a ratio that you have and see how it works out. The auto trans is quite tall geared.


~John
 
There were 3.73 ratios available in some markets for the 80 series front diff, and 3.70s for the 9.5" rear are common in earlier Cruisers.

These front gears are not that common, they are not found in North America, and are quite expensive.

I'd stick with a ratio that you have and see how it works out. The auto trans is quite tall geared.


~John

I've seen 3.90's, but not 3.73's for the HP front.

In any event, I'm going to get the swap going with stock gears and 33's first, and see where the revs are and how it drives. At least I have a plan of action in case I need to get the revs down.

Thanks everyone for your input!
 
3.73 would be too low. Remember that the AW450 has a much higher overdrive ratio than a standard A442F, 0.703 as opposed to 0.765. That is a significant difference. By my calculations 4.10s on 33s with AW gearing puts you in the sweet spot for a torque curve around 1600 rpms. You want to be slightly above torque peak at cruise so you don't fall off if you hit a hill etc. That is the way the FZJ is set up currently (easy to fall off the torque curve at 2000 or so RPMS) and it totally sucks.
 
with the standard drive line on 33 it will still be up at 2600/2700rpm 105kmh (65mph) I am chasing the same thing after getting the right work done to the mighty 1hd-t now makes more torque and lower than standard now making 5th gear pull better than 4th on the highway which is not good for 5th gear but the 3.73 on 33 will give you 2400ish rpm which is where I want to be but the 3.9 sound interesting
 
Cheapest route would be to move the steering to the front via Hellifire knuckles or Slee's highsteer stup or just a JDM drivers steering arm and run a low pinion 8" which should be stout enough in a 3 sumthin ratio gear set. Hell you could could probally do a staight trade for a LP Elocker 3rd with the right gearing.
 
Considering building a hybrid axle with the 9.5" diff and the 80 series knuckles and using new parts where possible.

How does that compare, price wise, with getting something like a Trail-Gear 609 or a Currie RockJock? I figure that the 609 or RockJock will be more expensive, but it would be significantly stronger.
 
i just got my diamond diff from Brian just over a month ago.. very nice stuff.. i got this front diff to match the 80 series front wms but mine has the cruiser 9 inch center and the pumpkin is set to the 60 series offset to match my truck..

if you are putting this diff into your 80, i would thing you would be better to have 80 series knuckle balls installed onto your diamond diff rather than the minitruck stuff.. at least you can use all of your existing steering components and it will be more or less a simple bolt in back into your truck.

for my axle I chose to not go with the 80 series knuckle balls due to there being no real good options for aftermarket knuckles and arms.. there is the hellfire fab stuff if he is still making stuff but i dont like his steering arms and by law you cant have welded steering components and i drive my truck everywhere.. he should have went to the 6 stud option and kept everything common so a person could use lukes 4x4 labs steering arms or trails marts and marlins 25mm bearing upgrade and i think it would have been a bigger hit..

P1020622_zps1caa7f37.jpg
 
i just got my diamond diff from Brian just over a month ago.. very nice stuff.. i got this front diff to match the 80 series front wms but mine has the cruiser 9 inch center and the pumpkin is set to the 60 series offset to match my truck..

if you are putting this diff into your 80, i would thing you would be better to have 80 series knuckle balls installed onto your diamond diff rather than the minitruck stuff.. at least you can use all of your existing steering components and it will be more or less a simple bolt in back into your truck.

for my axle I chose to not go with the 80 series knuckle balls due to there being no real good options for aftermarket knuckles and arms.. there is the hellfire fab stuff if he is still making stuff but i dont like his steering arms and by law you cant have welded steering components and i drive my truck everywhere.. he should have went to the 6 stud option and kept everything common so a person could use lukes 4x4 labs steering arms or trails marts and marlins 25mm bearing upgrade and i think it would have been a bigger hit..

P1020622_zps1caa7f37.jpg


I'm not an expert but I think it will be tough to turn with those axles in the front! :hmm::lol:
 
fj60 fa on an fj80

It's about time I find someone not afraid of the dark. This is the same thing I am trying to do due to what I have available and c$$h. I have an 80 that came w/out the front axle and I have a 60 the body is shot but as GOD is my witness and rveryone that was there my 60 pulled two 20ft alluminum containers to straighten them for a home build, one side was flat the other was 8ft from a more than 45degree incline w/achain so I know how powerful a 62 is. Thats my build in the process of getting all the parts. let me know how it turns out.
have fun
 
Check out this months 4wd Toyota Owners magazine. They add fj80 knuckles to a fj40 housing. Not sure if it will help you out but will work the same with the 60 housing. I have also seen guys lengthen the 60 housing tubes, and with the 80 knuckles you could use your stock steering. You can achieve what you are wanting to do a couple of different ways just depends on how much you want to spend.
 

Users who are viewing this thread

Back
Top Bottom