Topic: After some d/d diff options and ratios help

[john90lux]

My car is a d/d doing 60mile round trip 5 days a week to work, (not on fwy)
I wheel about 2x a month and travel approx 100mile there and back

At moment I have 32.5x10.5 daily and when wheeling 35x12.5
The car is very slow with both sets of tyres but 1st high is a joke with 35's

I'm looking at steeping to 37x12.5 for play, and keeping 32.5x10.5 daily
Car was factory 29" and 4.3 3rd
So 4.88 would be perfect for my 32.5 daily but not so perfect on weekend


I'm looking at a few gear options genuine and nitro, 4.85, 4.88, 5.13 and 5.29
Don't want to brake the bank, and all prices are in Aus $$ paying for centre rebuild only

Will genuine 4.88 witch are thinner keep up running 37's or even 33's daily?

Keep 55" axel

$3050 genuine second hand 4.88 centre with rcv axels front and rear

$4150 nitro 4.88 or 5.29 with rcv axels f&r

$4450 80 series hp front with nitro 4.88 or 5.29, rcv axel f&r

Step up to 63" axels will also require new rims witch I have prices yet

$4600 80 series hp front complex diff and and late model 8.8" centred rear diff with 4.88 nitro gear and histeer arms

$4600 80 series hp front complete front and complete flooring rear right offset diff with 4.88 or 5.29 nitro gear on stock axel with histeer arms + need to move gas tank

$4600 complete h260 front and h260 flooring centre rear with 4.85 or 5.19 nitro gears on stock axel and custom histeer arms

[H8PVMNT]

I vote 5.29 Nitro with RCV front, leave the rear axle shafts alone because they rarely break.  To tell the truth I kind of like the narrow track mini-truck axles too.

[john90lux [OP]]

Not changing rear axels will save me $950
Will nitro 5.29 handle and last daily driving, would be fitting auto locking lockers at same time

[Ritchie]

My truck is a DD and has 5.29 Yukon R&P and an auto trans.  No issues at all.

Hope this helps you.

[BoG-ToY]

Dual cases...
Stock gears.
This will keep you super happy with the 32.5s daily, and still drivable off the high speed roads in 2.28 low.
You could still use high with the 37's if you had to do a long highway stretch.
Since you are concerned with cost, but mentioning the fj80 stuff,
You can re-drill or re-use parts from an fj80 when doing the swap. A rear fj80 driveshaft is almost perfect when running duals and a lift, same thing with the front(measure measure measure, cool thing is if you move your axles to match the stock fj80 shafts those are cheap non custom shafts as well) You need 7/16 or 11mm bolts for the rear. I re-drilled my flanges after a center punch.
If you can run dual 2.28x 4.7 you would have lots of gears options to keep you happy, the nice thing is keeping stock diffs means cheap replacements.

You did not mention what engine transmission or transfer case you were running so this could all be different. This is assuming a w56 or g-series.

[BoG-ToY]

Oh yeah, if you move your front cv flange out back, and your rear flange up front in the cases, the cv flange fits the fj rear shaft better when re drilled and I think the fj80 front shaft(non-cv) fits the rear flange I believe

[H8PVMNT]

Not changing rear axels will save me $950
Will nitro 5.29 handle and last daily driving, would be fitting auto locking lockers at same time

I haven't ran Nitros myself but with any R&P if they are set up right they should last a good long time.  I am currently running a brand called G2 but I only have like 25K miles on them.  So far so good.

[john90lux [OP]]

I have a G series box behind a 3L 2.8 non turbo Diesel engine 90hp 140ftlb (when new but has 250k mile on it)
Many here just fit a turbo and run 4.88 3rd with 35's but the gearboxs don't seem to last and brake 5th with the extra power
Next to no one except compertishion trucks run above 35"

I've orders a 4.7 ratio dual witch should be here in 8-12weeks (sea freight)
I was told this was a better ratio to get as I have 3 low options
But I can onsell the 4.7 and keep the 2.x that the box has

Diffs, most are saying stick with the factory? Not jump to 80's width, I can get 60's but I haven't seen high steer in rhd for them

Just need to get axels right as the price is too high to make a mistake with the regearing or axel choise

[BoG-ToY]

See how you like your duals with the 4.7 ... You might not care to spend the money on diffs if you do most of your driving with 32s

[john90lux [OP]]

Down here we don't do a lot of crawling, mostly mud and dirt or open country hilly stuff,
So might be better with some 4.88 to move the torque for 32.5" tyres where I need it at least then when in high range 4x4 it should be close to what I have now with 4.3 and 32.5"

I know factory 4.88 are different to all others but are they equal I strength to aftermarket 4.88 fitted to 4.3 3rd housings

[BoG-ToY]

2667 rpm @ 60mph 4th gear.
2267 rpm @ 60mph 5th (.85)
4.3mph @ 750 rpm 3.9 1st
All 32" tires

4540 rpm @ 60 5th 2.28 low
5341 rpm @ 60 4th 2.28 low
2.2mph @ 750 rpm 1st 2.28 low
All 37s
30 mph @ same rpm as 60 mph for 4.3 with 32s

So driving in low with 37s would suck on the street
There it is!
If you can deal in mph 4lo.com is a good website for engineering and reverse engineering your speed and rpm for different axle ratios, different tire sizes, as well as calculating for each gear option in your transmission. Can really be useful to get an idea as how fast you will need to be going to idle in first and how fast your engine will be screaming at highway speeds

[john90lux [OP]]

My truck weighs 4750lbs or 5000 with me in it, add 3 kids and wife around 5500 and if we going away I'm just on 6000lbs
Most of my local driving is mud, clay, bogholes or deep ruts, so 4low is where I like to be but at 2500-3000rmp 30-35mph is a tad to quick with my 32.5 on I'm 25-30mph witch I think is better but still quick but when coming up to hills I have to drop down to 2nd low and sometimes even 1st

When in high country it's mostly hills, dirt, sand and unsealed road, nothing hard, stock 4wd with decent stock size tyres will do it all, and we sit on about 40mph, if I'm lazy or it's far away I do this with my 32.5" as I can't get over 55mph with 35's on

I think 4.88 might be best all round, but 5.29 might be better as do very little hwy driving unless I'm on a big trip so 5th should put me about 2750rmp at 60mph

[BoG-ToY]

on all my 35" tire rigs 5.29 was my go to gear.  they are CHEAP on ebay for the gear set...

[john90lux [OP]]

Not everything is so cheap when in another country
$599 nitro landed at my door and $250 for master install kit with soild spacer at my door
Is the cheapest price I've got, freight is the killer to Australia so on some things it's better to buy from an agent with warranty

[BoG-ToY]

For sure,
I have a friend in the Uk. It's cheaper for him to have me order him head studs, get them shipped to me then have me re-box and ship to him!

[BoG-ToY]

20 lbs weight limit, if packaged right you could probably get both ring and pinion sets, both instal kits and both solid spacers in either the $75 or $99 box.
They have a $35 box but it's small and 4lbs limit.

[BoG-ToY]

Motive or g2 brand about $160 a set on eBay
$300 for a pair  $26 each for solid spacers
Install kits are $150 each with full bearings
About $750 shipped for everything needed to do the install
(As long as it's under 20 lbs)


Thats USD looks like about $1000 Australian
So you probably got a good deal

[john90lux [OP]]

My prices were each not pair,
I've seen g2 advertised on eBay but no one sells that brand over here, so figured it might not be worth the it if no one sells it,

[BoG-ToY]

OUCH.... So some money could be saved.....
do you get charged duties or anything if you cousin is sending you your birthday present?

[john90lux [OP]]

10% total price including shipping cost

Any idea about fitting 60 series axels
I know My six shooters will bolt straight in front so high steer I can use what I have but gain 3" more width + 9.5" centres
Rear I know is offset but I will have move fuel tank same as 80's?
Or can the back of housing be cut off and turned upside down so I can turn the entire diff around and have 3rd on left side

Have been offered a complete set for same price as a hp 80 series centre, I will still need to regear and rebuild,

[BoG-ToY]

Fj cruiser rear axle is an 8" diff. And like 64.25 wide. Newer 4Runner and Tacoma rear axles as we'll,

[john90lux [OP]]

Readly available axels down here in are
Fj40 58" full floating offset rear 9.5"
Fj60 58" full floating offset rear 9.5"
Fj70-78 sizes vary and front and back are differed by 1" with 9.5" flooring rear and either 8 or 9.5" front
Fj80 63" full floating offset rear 9.5" and 8" front
New fj 64" centred 8" rear
Pre 05 hilux Ifs 58" centred 8" rear
05-16 hilux ifs and pardo 63" centred 8" rear
Post 16 hilux ifs 64" centred 8.8" rear

70 series up 3rds alone go for $800 second hand and broken $450-500
Where as 40 and 60 series you'll buy complete diff for 4-500

It's just fitting a matching front and rear