Outer Limits 4x4 Board

Posted: **Sun Feb 29, 2004 9:14 pm**

I have just picked up a 86 NT sierra and am looking at running 31's for the time being.
I will be putting in a 1lt transcase to lower the gearing but I also have the 1lt diffs.
Now I know the 1lt diffs are 4.1 's and the NT's are 3.9 so the 1lt diffs would be better for the gearing.
But how are the 1lt diff for strength. I think someone once told me they were not as strong as the 1.3 diffs.

Also if they are a bit weaker, are the diff centres for these two interchangable as I think I remember reading that they may not be.

i wish I had a better memory!!!!!!!!!!!!!!!!!!!!!!!!!!!

Posted: **Sun Feb 29, 2004 9:21 pm**

31s will be fine

Posted: **Sun Feb 29, 2004 9:33 pm**

1 and 1.3 centres are not interchangeable.....my 1.0 litre diffs are coping well, but not much after market stuff for them, ie lockers etc. christover

Posted: **Sun Feb 29, 2004 9:45 pm**

Cool thanks! I am going welded diffs anyway so I wont have to worry about lockers.
I will soon have some birfields, there shouldn't be any dramas with those though, will there?

Posted: **Sun Feb 29, 2004 10:20 pm**

Wolverine wrote:Cool thanks! I am going welded diffs anyway so I wont have to worry about lockers.
I will soon have some birfields, there shouldn't be any dramas with those though, will there?

dont know much about birfields, both my diffs are welded, I run a 1.3 motor into my 1.0 litre gearing, it pulls 31's OK...hopper be better, but that relies on winning lotto.. also the extra clearance under the 1 litre diffs is great, christover

Posted: **Sun Feb 29, 2004 11:54 pm**

so to keep things cheap do you reckon I change over to the 1lt diffs for better gearing or is this a backwards step.

Another option I have is the rocklobster conversion as I now believe the 1lt case I have is a 84 so I just need to find someone who does it over in Perth.

Any thoughts

Posted: **Mon Mar 01, 2004 6:33 am**

Wolverine wrote:Cool thanks! I am going welded diffs anyway so I wont have to worry about lockers.
I will soon have some birfields, there shouldn't be any dramas with those though, will there?

I wouldn't bother with birfields if your only running 31's

My 2c

Posted: **Mon Mar 01, 2004 8:43 am**

Wolverine wrote:so to keep things cheap do you reckon I change over to the 1lt diffs for better gearing or is this a backwards step.

Another option I have is the rocklobster conversion as I now believe the 1lt case I have is a 84 so I just need to find someone who does it over in Perth.

Any thoughts

the difference between 3.9 and 4.1 wont be worth the trouble, but the extra diff clearance is very good. I'd stick to the 1.3 diffs with 1.0 transfer case. rocklobster is just 2 sets of gears welded together I think. not a very reliable outcome, as 2nd hand 4:1 rockhoppers are now getting cheaper, as the money guys want 6:1 hoppers.

Posted: **Mon Mar 01, 2004 10:07 am**

speaking of diff strength, has anybody ever run 35x15x15 boggers in WT diffs? how long did they last?

Posted: **Mon Mar 01, 2004 10:19 am**

speaking of diff strength, has anybody ever run 35x15x15 boggers in WT diffs? how long did they last?

Myself and greg are running 34 x 9.50 swampers with low gearing and lockers and haven't broken them yet (I have had this setup for a few yearsd and greg a couple) Bigsteve has just put 34 x 10 on his but hasn't tested them yet and love_mud has 35 claws on his.

In Melbourne and our conditions of more mud and low traction surfaces you should be ok as long as you don't flog the living crap out of it. On rock or high traction surfaces you would probably find the strength to be lacking[/quote]

Posted: **Mon Mar 01, 2004 10:28 am**

grimbo wrote:
Dawg wrote:speaking of diff strength, has anybody ever run 35x15x15 boggers in WT diffs? how long did they last?

Myself and greg are running 34 x 9.50 swampers with low gearing and lockers and haven't broken them yet (I have had this setup for a few yearsd and greg a couple) Bigsteve has just put 34 x 10 on his but hasn't tested them yet and love_mud has 35 claws on his.

In Melbourne and our conditions of more mud and low traction surfaces you should be ok as long as you don't flog the living crap out of it. On rock or high traction surfaces you would probably find the strength to be lacking

[/quote]

Dawg, If you find that they are no good - give them to me and i will work out how to run them

Posted: **Mon Mar 01, 2004 10:50 am**

grimbo wrote:
speaking of diff strength, has anybody ever run 35x15x15 boggers in WT diffs? how long did they last?

Myself and greg are running 34 x 9.50 swampers with low gearing and lockers and haven't broken them yet (I have had this setup for a few yearsd and greg a couple) Bigsteve has just put 34 x 10 on his but hasn't tested them yet and love_mud has 35 claws on his.

In Melbourne and our conditions of more mud and low traction surfaces you should be ok as long as you don't flog the living crap out of it. On rock or high traction surfaces you would probably find the strength to be lacking

[/quote]

I have run 33x12.5 swampers and 35x12.5 claws for a while now, the biggest issue I have found is actually fatuige over time.. IE cracking the diff housing in a horizontal plane... most just stress from torque applied over the past 80,000kms I have run with 32's and bigger.

If your sensible they should last OK .. (depending on the surface your running on as well like grimbo said)

Posted: **Mon Mar 01, 2004 1:05 pm**

Horizontal crack like this !!

Posted: **Mon Mar 01, 2004 1:06 pm**

Dick wrote:Horizontal crack like this !!

Nah in the actual diff housing itself .. in the long side axle tube

Posted: **Mon Mar 01, 2004 1:10 pm**

Oh I see.. :oops:

Did u know that Vitara front diff will bolt into Sierra rear hsg .. Seen one yesterday, for what its worth...

Posted: **Mon Mar 01, 2004 1:16 pm**

Dick wrote:Oh I see..
Did u know that Vitara front diff will bolt into Sierra rear hsg .. Seen one yesterday, for what its worth...

They do .. but due to the marginal strength of the alloy housing on the majority of vit diffs.. on a modified sierra they are begging for expensive trouble :shock:

Posted: **Tue Mar 02, 2004 11:17 am**

love_mud wrote:
Dick wrote:Oh I see..
Did u know that Vitara front diff will bolt into Sierra rear hsg .. Seen one yesterday, for what its worth...

They do .. but due to the marginal strength of the alloy housing on the majority of vit diffs.. on a modified sierra they are begging for expensive trouble

Why would Suzuki ever make a diff with Alloy housing.. got me stuffed.. My GV steel one is being assembled now, complete with A/L and I am adding an extra mount to be safe.. Next problem C/V's I assume ! :?:

Posted: **Tue Mar 02, 2004 11:19 am**

Dick wrote:
love_mud wrote:
Dick wrote:Oh I see..
Did u know that Vitara front diff will bolt into Sierra rear hsg .. Seen one yesterday, for what its worth...

They do .. but due to the marginal strength of the alloy housing on the majority of vit diffs.. on a modified sierra they are begging for expensive trouble

Why would Suzuki ever make a diff with Alloy housing.. got me stuffed.. My GV steel one is being assembled now, complete with A/L and I am adding an extra mount to be safe.. Next problem C/V's I assume !

Lighter = better fuel economy, the only reason I can think of ..

Posted: **Tue Mar 02, 2004 10:29 pm**

What breaks first? the chicken or the egg?

Seriously the IFS alloy front end has to be substantially lighter than the widetrack front end, with the benefit of 5" more width.

If I get around to ripping all the bits out in the near future I'll weigh them.

there was at least SOME method in the madness I am sure.

Outer Limits 4x4 Board

Diff strength

Diff strength