Diff Gear ratios

[XLS PB Challenger]

it is another complete diff from a pb with factory locker
i have done some extensive research and mods to it with a big machining bill to go with it
the diff so far owes me over $1000 in just machining stuff with out the cost of the diff it self
and i have done a fare bit of moding it my self so im glad i didnt pay some one to do it
lucky im a tinkera and a mechanic to do so

now im up to the reassembly part i need new bearings and seals and i have a 4.3 factory rear diff lock center to fit in the pb

i have the front sorted it all ready has a 4.3 ready to go into it for the trans plant nothing much to do with the machining on that one little bit mucking around and she should be in

just have had a ruff last 8 months with personal issues and family issues and work related things and the diff isnt on my radar at the moment
nor is the challenger im getting to the stage where im over it
it will be going to the dealers soon for a trade in had a enough of the pb crap fuel and power/torque for towing it is a crap 4x4...

sorry rant over

Hi Coughy,

Just wondering if the diffs might be for sale if the challenger has gone to the dealer for a trade in?


Cheers
Paul

[PC Challenger]

Ok. I started this thread along time ago. And im back thinking about doing it. I have a mate that did the 4.3s. And it was a direct install. He said it helped. But would recommend the 4.6s for towing. This is the rpms ive worked out.

Stock 3.917
Either 4.3 or 4.6
Diff housing 12 bolts

Rpm at 110 km with 3.917 in 5th
245 / 70 /16 - 2391 rpm
265 / 70 / 16 - 2304 rpm

Rpm at 100km with 3.917 in 4th
245/70/16 - 2766 rpm
265/70/16 - 2666 rpm

Rpm at 110 km with 4.3 in 5th
265/75/16 - 2446 rpm
255/85/16 - 2341 rpm

Rpm at 110 km with 4.6 in 5th
265/75/16 - 2617 rpm
255/85/16 - 2504 rpm

Rpm at 90km with 4.3 in 4th
265/75/16 - 2556 rpm
255/85/16 - 2447 rpm

Rpm at 90 km with 4.6 in 4th
265/75/16 - 2735 rpm
255/85/16 - 2617 rpm


Anyonr no if theres 4.6 that will drop straight in?

[old Jack]

Hi PC,

Your numbers do not look correct at a quick glance.
Method for working this out in post #16 of this thread.

https://www2.pajeroclub.com.au/forum/showpost.php?p=453764&postcount=16

My calculations have an auto trans fitted with stock tyres at 100kph gives an engine rpm of 1953 with 3.917 ratio, and with 4.3 diff ratios the engine rpm would be 2145 rpm.

OJ.

[PC Challenger]

Are these correct for a manual
As it all off a app

[nj swb]

Anyonr no if theres 4.6 that will drop straight in?

The Gen 2s had a 4.636 ratio that I would expect to drop in, and it just so happens that I have one for sale. https://www2.pajeroclub.com.au/forum...ad.php?t=59242

The housing from which this centre was removed now has 4.3s from a Triton - a straight forward swap.

I believe all the 8" high pinion fronts are compatible - if you can find the ratio it should drop into your housing. 4.3s from a Gen 4 dropped into my NJ housing.

[nj swb]

Are these correct for a manual
As it all off a app

The 5th gear ratio does appear right for a manual - OJ was talking auto.

Interesting that your friend thinks 4.6 would be better for towing. I put 4.3s in Shorty, and I had somebody try to convince me I should go 4.6. But Shorty isn't for towing, it's smaller / lighter, with the 3.2 and Auto to help out off the line.

[PC Challenger]

The 5th gear ratio does appear right for a manual - OJ was talking auto.

Interesting that your friend thinks 4.6 would be better for towing. I put 4.3s in Shorty, and I had somebody try to convince me I should go 4.6. But Shorty isn't for towing, it's smaller / lighter, with the 3.2 and Auto to help out off the line.

Its more for getting off the line.

I have 33.1" muddys. And on a very steep hill i actually get stuck if i stop.
No matter how high i rev or ride the clutch.

I have 3.15 crawlers. So low range i can just release the clutch with no accelerator. And it will just walk no matter how steep.

I want to get a pop up caravan. And either drive with 33s or 32s depending on what im doing.
And dont want to keep using low range

[nj swb]

Its more for getting off the line.

I have 33.1" muddys. And on a very steep hill i actually get stuck if i stop.
No matter how high i rev or ride the clutch.

I have 3.15 crawlers. So low range i can just release the clutch with no accelerator. And it will just walk no matter how steep.

I want to get a pop up caravan. And either drive with 33s or 32s depending on what im doing.
And dont want to keep using low range

Fair enough.

Another way to look at it (with the help of a calculator):

Pick any speed, in any gear. For every 3,917 rpm with stock diffs, the engine will go to 4,636 rpm with the 4.636 diffs. So, divide current rpm by 3.917, multiply by 4.636 and that's the new revs your engine would spin at the same road speed.

To shorten things a little, 4636 / 3917 = 1.184.

So, for every 1000 rpm now, the new diffs would require 1184 rpm for the same road speed.

2000 rpm now would go to 2368 rpm at the same speed.

Your example earlier, with 110km/h on 265/70 R16 at 2,304 rpm (if that's correct?) would become 2,728 rpm on 4.636 diffs.

[PC Challenger]

Fair enough.

Another way to look at it (with the help of a calculator):

Pick any speed, in any gear. For every 3,917 rpm with stock diffs, the engine will go to 4,636 rpm with the 4.636 diffs. So, divide current rpm by 3.917, multiply by 4.636 and that's the new revs your engine would spin at the same road speed.

To shorten things a little, 4636 / 3917 = 1.184.

So, for every 1000 rpm now, the new diffs would require 1184 rpm for the same road speed.

2000 rpm now would go to 2368 rpm at the same speed.

Your example earlier, with 110km/h on 265/70 R16 at 2,304 rpm (if that's correct?) would become 2,728 rpm on 4.636 diffs.

Yer. But this app takes the tyres in consideration.
Thats why on the 4.3 and 4.6 the tyre size is larger

[4wd26]

I have the 4.6 gears in my Triton. Works nicely with 32” tyres when towing and 33” tyres when off-road. I started with 4.1 gears though.

I now no longer require the manual torque lockup switch in the auto when towing as it is a much more factory ratio (with larger tyres)

It is the Pajero gears I used but you need to confirm you have the 12” diff and axles, otherwise the earlier gen 2 gears will work with the smaller diff.

Will be important as the axles and therefore the rest of your driveline.

Could fit a lsd into your open diff, cannot retro fit a factory locker as the axle length is longer in the Triton/ challenger than the doner Pajero.

[PC Challenger]

I have the 4.6 gears in my Triton. Works nicely with 32” tyres when towing and 33” tyres when off-road. I started with 4.1 gears though.

I now no longer require the manual torque lockup switch in the auto when towing as it is a much more factory ratio (with larger tyres)

It is the Pajero gears I used but you need to confirm you have the 12” diff and axles, otherwise the earlier gen 2 gears will work with the smaller diff.

Will be important as the axles and therefore the rest of your driveline.

Could fit a lsd into your open diff, cannot retro fit a factory locker as the axle length is longer in the Triton/ challenger than the doner Pajero.

Mm well i have factory rear locker and e locker in front. Differently want to be keeping them.

A mate in a MN triton with 12 bolt rear diff managed to keep the lockers on 4.3s

[nj swb]

Mm well i have factory rear locker and e locker in front. Differently want to be keeping them.

A mate in a MN triton with 12 bolt rear diff managed to keep the lockers on 4.3s

The locker is in the diff centre, which gets bolted to the crown wheel. If you already have locker and axles, no problem keeping them.

[4wd26]

The locker is in the diff centre, which gets bolted to the crown wheel. If you already have locker and axles, no problem keeping them.

As above, was just a heads up if you wanted to change

[PC Challenger]

Ive sourced some 4.636 out of a nl Pajero.
Its 8 inch front and a 9.5 inch rear " 12 bolt"
Just the gearsets are $400 for both.
Will confirm with my diff guy.