high pinion

[tasman]

just want to double check, i've got 4.6's so i would need a front with the 4.6 ratio to work.

[stimpy]

did mine last week used the lsd out of the rear put it in a front center and changed the tailsharft flange over and it went in no probs at all

[twodiffs]

This mod obviously cannot be done with the rear ARB locker can it??
(31 vs 33 spline).

So if I want to go high pinion rear then you have to use an ARB front locker correct??.......if so then 'buggger'

[A.J.]

No, that's incorrect.

Rear diff, rear locker. That's it.
The only things "front" are the crownwheel+pinion and the centre-housing (third member).

EDIT: The lockers are physically the same on the outside! Only the internals (spider gears) differ from FR to RR. 33 vs. 31 spline.

So again, this is what you need:

-Rear locker or LSD
-Front crownwheel and pinion
-Front centre-housing (third member, the cast bit that bolts in)
-Move the filler plug up 2-3"

That's it.

[SIM79]

-Move the filler plug up 2-3"

I have been lazy and haven't moved mine I just jack the diff up high to get extra oil in.

[twodiffs]

No, that's incorrect.

Rear diff, rear locker. That's it.
The only things "front" are the crownwheel+pinion and the centre-housing (third member).

EDIT: The lockers are physically the same on the outside! Only the internals (spider gears) differ from FR to RR. 33 vs. 31 spline.

So again, this is what you need:

-Rear locker or LSD
-Front crownwheel and pinion
-Front centre-housing (third member, the cast bit that bolts in)
-Move the filler plug up 2-3"

That's it.

okee dokee...so I find a front centre with matching gearing, get my rear locker installed into the housing and presto put it into the rear diff.

Sorry i'm struggling with this - so what are the spider gears and wouldn't the front spider gears be 31 spline....how does that work with rear 33 spline axles??

[twodiffs]

No, that's incorrect.

Rear diff, rear locker. That's it.
The only things "front" are the crownwheel+pinion and the centre-housing (third member).

EDIT: The lockers are physically the same on the outside! Only the internals (spider gears) differ from FR to RR. 33 vs. 31 spline.

So again, this is what you need:

-Rear locker or LSD
-Front crownwheel and pinion
-Front centre-housing (third member, the cast bit that bolts in)
-Move the filler plug up 2-3"

That's it.

okee dokee...so I find a front centre with matching gearing, get my rear locker installed into the housing and presto put it into the rear diff.

Sorry i'm struggling with this - so what are the spider gears and wouldn't the front spider gears be 31 spline....how does that work with rear 33 spline axles??

Rear locker has carrier splines for rear axles.....correct??
Do I get a chocolate this time AJ?

From what SIM said it solved his vibes and grinding completely....is this mod better or more effective than fitting adjustable rear upper & lower control arms...anyone?

Cheers for your patience

[A.J.]

okee dokee...so I find a front centre with matching gearing, get my rear locker installed into the housing and presto put it into the rear diff.

Sorry i'm struggling with this - so what are the spider gears and wouldn't the front spider gears be 31 spline....how does that work with rear 33 spline axles??

What is it with you and your front spider gears? The front is COMPLETELY IRRELEVANT for this, you are using a REAR locker/LSD/whatever which has 33spline internals

You only use the front third member (housing) and take the crownwheel of the carrier (normally open diff) and throw the diff out!

Then you use YOUR rear centre carrier/LSD/locker/ whatever.

All good now?

[twodiffs]

okee dokee...so I find a front centre with matching gearing, get my rear locker installed into the housing and presto put it into the rear diff.

Sorry i'm struggling with this - so what are the spider gears and wouldn't the front spider gears be 31 spline....how does that work with rear 33 spline axles??

What is it with you and your front spider gears? The front is COMPLETELY IRRELEVANT for this, you are using a REAR locker/LSD/whatever which has 33spline internals

You only use the front third member (housing) and take the crownwheel of the carrier (normally open diff) and throw the diff out!

Then you use YOUR rear centre carrier/LSD/locker/ whatever.

All good now?

Well excuse me for not being overly familiar with the dynamics of the centres YET...but i'm working through it, I hope thats alright with you!

What has thrown confusion into the matter for me is comments made by ELF_83 and TUF045 on page 1.

(ELF_83 wrote:
all we are doin is runnin front centres in the rear. that all it is and we (well atleast myself and russ, can't speak for the rest) are runnin moded/custom arb front lockers.

TUF045
you can just use a std rear arb locker. the only diffrence is the spline count on the hemisphere side gears the front is 31 spline the rear is 33.
have had a play with these and have found they end up cracking the teeth on the crown wheel and they make noise when coasting).


Their posts are more than likely valid (no offence to the authors
But it started me thinking "why modded/custom lockers" and "why cracking the teeth on the crown wheel"

Note: You still haven't answered my question aj, what are the spider gears? or is that a nickname for other components.

[76patrol]

well my experiment with itialian gears waas a faliure. dont use these if your running a hp rear. on the weekend mine went bang. although that is with 37"s though. got a genuine center in now so we'll see how that works.

[twodiffs]

I've got a mate with a cruiser who fitted italian gears....same thing happened . Big tyres and lockers as well though so it worked hard.

[SIM79]

From what SIM said it solved his vibes and grinding completely....is this mod better or more effective than fitting adjustable rear upper & lower control arms...anyone?

I had adjustable uppers and longer lowers with zero vibrations and that bloody grinding noise. The high pinion is the only thing that could stop that annoying grinding noise .

[A.J.]

Sorry dude, I wasn't beeing rude

This should answer your question:


EDIT: And with running "custom/modded front lockers", they mean the changed the spider gears to make it 33 spline, which technically makes it a rear locker. Front and rear lockers are the same! Only the spider gears differ (33 to 31 spline) which can be changed.

But as said before, if you have a rear locker, you just use that, if you'd have a front one, you'd have to change the spider gears to fit 33 spline axles.
With "using the front centre" they don't mean the actual centre (LSD or open, also called hemisphere) but rather the housing (centre part off the diff, that bolts into the pumpkin).
So that's all you need from a front diff, the housing and the gears.

I hope this helps mate

okee dokee...so I find a front centre with matching gearing, get my rear locker installed into the housing and presto put it into the rear diff.

Sorry i'm struggling with this - so what are the spider gears and wouldn't the front spider gears be 31 spline....how does that work with rear 33 spline axles??

What is it with you and your front spider gears? The front is COMPLETELY IRRELEVANT for this, you are using a REAR locker/LSD/whatever which has 33spline internals

You only use the front third member (housing) and take the crownwheel of the carrier (normally open diff) and throw the diff out!

Then you use YOUR rear centre carrier/LSD/locker/ whatever.

All good now?

Well excuse me for not being overly familiar with the dynamics of the centres YET...but i'm working through it, I hope thats alright with you!

What has thrown confusion into the matter for me is comments made by ELF_83 and TUF045 on page 1.

(ELF_83 wrote:
all we are doin is runnin front centres in the rear. that all it is and we (well atleast myself and russ, can't speak for the rest) are runnin moded/custom arb front lockers.

TUF045
you can just use a std rear arb locker. the only diffrence is the spline count on the hemisphere side gears the front is 31 spline the rear is 33.
have had a play with these and have found they end up cracking the teeth on the crown wheel and they make noise when coasting).


Their posts are more than likely valid (no offence to the authors
But it started me thinking "why modded/custom lockers" and "why cracking the teeth on the crown wheel"

Note: You still haven't answered my question aj, what are the spider gears? or is that a nickname for other components.

[twodiffs]

From what SIM said it solved his vibes and grinding completely....is this mod better or more effective than fitting adjustable rear upper & lower control arms...anyone?

I had adjustable uppers and longer lowers with zero vibrations and that bloody grinding noise. The high pinion is the only thing that could stop that annoying grinding noise .

Cheers sim, what I was wanting to hear .

[twodiffs]

A.J. - thats perfect, thanks for going to the effort of posting the schematic.

Thats cleared things for me .

Cheers.

[twodiffs]

From what SIM said it solved his vibes and grinding completely....is this mod better or more effective than fitting adjustable rear upper & lower control arms...anyone?

I had adjustable uppers and longer lowers with zero vibrations and that bloody grinding noise. The high pinion is the only thing that could stop that annoying grinding noise .

Cheers sim, what I was wanting to hear .

Edit. I don't really have the vibes either but that frigggin grinding noise backing off the go fast pedal around 120km... makes me cringe like when the teacher dragged the fingernails down the blackboard

[Rolly]

i ran hi pinion rear set up this year at tuff truck and stripped the teeth off the crown wheel .
if you have the money get a new crown wheel and pinion and put in the rear because gears that have run one way for a long time dont like to be run backwards on the other side of the teeth.
the other prob i had which was a pita was getting hung up on the rear diff heaps because with the shape of the diff centre it wont slide over rocks at all its like throwing an anchor out the back.

[nastytroll]

i ran hi pinion rear set up this year at tuff truck and stripped the teeth off the crown wheel .
if you have the money get a new crown wheel and pinion and put in the rear because gears that have run one way for a long time dont like to be run backwards on the other side of the teeth.
the other prob i had which was a pita was getting hung up on the rear diff heaps because with the shape of the diff centre it wont slide over rocks at all its like throwing an anchor out the back.

Proberly broke the pinion because the centre was stuck. Also driving on the week side of the gears would have amplified the problem. 40" stickies would not have helped either.

The crown wheels are different thickness between front and rear's too. From memory I think the crown wheel flange was different too.

[SIM79]

Has anyone had any strenght issues running gear ratio's 4.3 or 4.6 in a high pinion rear?

[toughnut]

This has been a great thread once the kinks were ironed out.

As for the diff getting hung up on rocks. Why don't people just make up a ramp that bolts/welds on to fix this? The other thing I'm curious about is, are these diffs prone to the same thing as *cough*s@#t*cough* toyota diffs that explode of you are reversing up a step or something like a macca's speed bump? Because you are effectively running in reverse most of the time.

[SIM79]

Is anyone running 4.3 or 4.6 in a high pinion rear?

[Bartso]

Is anyone running 4.3 or 4.6 in a high pinion rear?

i use to run a 4.3 high pinion rear with 44's i only ever broke axles

[Rolly]

just put in 4.3 ratios . a new crown wheel and pinion for the rear so it hasnt been run on the other side of the gears before .
also made up slide for bottom of diff so it wont get hung up .
i will let you know how it goes.

[slinky mav]

I cant get my head around why running the front Crown wheel and Pinion.
Wouldn't the rear crownwheel and pinion in there currently do the same job and run on the correct side not the reverse?

[SIM79]

i use to run a 4.3 high pinion rear with 44's i only ever broke axles

Thanks Bartso

just put in 4.3 ratios . a new crown wheel and pinion for the rear so it hasnt been run on the other side of the gears before .
also made up slide for bottom of diff so it wont get hung up .
i will let you know how it goes.

Keen to hear how this goes and see pics of the slide.

[SIM79]

I done it in my shorty, just mahe sure the pinion is done up tight and use locktite. Because it is a front diff in the rear and running in reverse the pinion nut can come loose.

Are there any warning signs/noises that let you know when you pinion nut is loose or starting to get loose?