Building a stronger front diff for my bj42 crawler (1 Viewer)

[simonliew]

Hi all,
I’ve installed 80 series axles with e-lockers front and rear on my bj42 rockrawker in 2007,modified the 80 knuckles to highsteer,5:29s,Long fields....after many years of wheeling,the front housing is bent,I broke the ring and pinion in Moab is 2013,now I’ve acquired the hellfire highsteer,60 series rear housing cut to 80 series width,my question is where can I get front 80 series long side axle with Long splines so l can use the 80 rear e locker in the front??
I already have the e locker....

 

[simonliew]

80 front ring gear

 

[White Stripe]

trail gear has them I am pretty sure. RCV probably does as well.

 

[jim land]

I thought that 5.29 was weaker than 4.11 and prone to pinion fail ,but in your case its your ring gear that broke

 

[jim land]

do you have a build thread of your 40 , are those rubber's 40'' ?

 

[spotcruiser]

Yep, I think you can get them from RCV. RCV is the original supplier of Longfields before Bobby passed away.

Toyota Axle Shafts

RCV Off-Road Performance Products - CV Joints, Axle Kits, Tools

 

[simonliew]

Hi Jim,yes those are 40s.
Don’t really have time to write a build thread,I’ve a shop and work on lots of jdm Diesel cruisers n Mitsubishi.
Short specs:
3B Diesel intercooler turbo
H55,marlin toybox 4.7
On board air York compressor
Roll bar is my air tank
Front bumper n inner front fender my vacuum tank for brakes
60 series front n rear springs
Trail gear steering ram n pump

Really want to 3 link the front but it cost a lot more to get all the parts to Canada
Plus I’ve two more bj42s and a fj55 to build.

 

[simonliew]

Yes 4:11 is stronger
I should have use 4:88, still strong enough and able to drive it on trails

 

[BlueCruiser84]

I think most people would tell you for a "stronger" diff you would want to forego the factory rear e-locker and install and ARB.

At the very least, you should mod the splines on the axle shaft in case you twist them. Are you leaving the removable cover on the diff?

 

[simonliew]

I was going to go with the arb cos I couldn’t find an 80 rear elocker around here,I fact I got it here,cost a bunch,then I found an elocker for cheap.
I know about the elocker if you break the axle it’s hard to remove the broken piece,but what’s the splines mod you’re talking about??
Yes I’m keeping the removable .

 

[Chris Wilcox]

I bought a rear From Bobby and then after he passed, a front from RCV. I sent them a sketch of what I was after and paid $290 USD in 2014. This is a picture of that sketch but you will have to measure your own length. I did this by sticking the diff in the center and determining the position of where the end of the axle should be relative to a datum. Then I removed the diff and installed the hellfire complete with an 80 series shaft I had to see how far in that went. Find the difference and then add/subtract that from the length of the shaft I used. This took some time and I was careful in the measuring, think machinist layout of a precision part. It all worked in the end

.

 

[White Stripe]

If you use 80 knuckle balls, and 100 side gears, I think you could use Nitro's 32 spline birfield/axle kit. Should be about 30% stronger than 30 spline shafts. But then you will need a 100 series locking collar and maybe a few other parts. Although, I have seen rigs with 30 splines up front get beat on pretty hard without issue.

 

[BlueCruiser84]

I was going to go with the arb cos I couldn’t find an 80 rear elocker around here,I fact I got it here,cost a bunch,then I found an elocker for cheap.
I know about the elocker if you break the axle it’s hard to remove the broken piece,but what’s the splines mod you’re talking about??
Yes I’m keeping the removable .

*Attention* I've never done it and I forget which side (passenger or driver) shaft you do this too. You machine the splines out from the middle of the long splined shaft. This way if the shaft twists or breaks the locking collar can still disengage and you can still get the third member out..... or something to that effect. Obviously more research would be necessary on your end, but this is the drawing I have saved on my phone. Maybe someone with more knowledge than me can chime in.

 

[simonliew]

Thanks bluecruiser.

 

[simonliew]

After some measuring,I’ve to move the passenger side spring pad 1.5” to the right and same as the drivers Long side.
So I ordered a short side axle 2” longer than stock and the long side axle 2” shorter with 4.5” splines for the elocker from trailgear, plus 30 splines birf...
All this just to move the pumpkin 2” to the left

 

[Mieser]

I have been looking at 100 series diff with the 32 spline shafts AND 32 spline pinion. Won't it bolt in place of the normal 9.5 3rd member?

 

[simonliew]

Hmmm can’t find much info on that
Plus I already have the 5:29 gears n lockers sitting here

 

[jim land]

with a h55 and toy box i don't see why you need 5:29 gears in the diff

 

[White Stripe]

I have been looking at 100 series diff with the 32 spline shafts AND 32 spline pinion. Won't it bolt in place of the normal 9.5 3rd member?

Yes it should bolt right in. Most of the 9.5 is mix n matchable from what I've read in Australian forums. They build toy axles to the max because Dana 60s and 14 bolts aren't plentiful down under.

 

[peesalot]

I asked just differentials that question and was told they will not, different offset or something. Then you gotta get custom 32 spline axles ??
A rear from a tundra would make a good chunk for the custom front.