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rear axles

jmangi62

Bronco Guru
Joined
Jul 28, 2013
Messages
2,469
Hey guys, just replaced the gears on the 9 inch to 4.56 to match the front axle, I have the factory limited slip, 70 lg bearing, can I install 31 spline axles to replace my current 28 spline axles without changing the LS? Jim:cool:
 

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bronconut73

Bronco Guru
Joined
Aug 7, 2012
Messages
9,916
I got side gears splined for 31 spline axles from WH that will fit in the stock carrier.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
What they said. So yes, you can do it on your existing carrier by swapping out the current 28 spline side gears to 31 spline side gears. Or change the limited-slip unit entirely.
But either way you're taking it all apart again.

Paul
 

Crush

Contributor
Bronco Guru
Joined
May 30, 2007
Messages
3,463
Loc.
Greenbottom, WV
So if i have a 3.50 28 spline trac-loc and want to go 4.56 and 31 spline i can do it on the cheap by getting the 31 spline side gears/axels/and 4.56. Guess i would also need the gear install kit but is there anything else needed to replace the side gears? Do it all at once the first time. Lol
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,875
More likely you will have to get a rebuild kit for the trac-lock too. They typically don't last very long and once you take it apart to replace the side gears you might as well do it right. You will also need a bottle of friction modifier to add into the gear lube when you refill the diff. I would use a solid spacer kit for the pinion bearing instead of the crush sleeve. Later model ford trucks and vans used 31 spline trac-locks.
 
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jmangi62

jmangi62

Bronco Guru
Joined
Jul 28, 2013
Messages
2,469
OK Thanks guys, I'm gonna install new seals and bearings on the stock 28 spline axles for now, then at some point get a new locker and 31s. Jim
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,875
if mostly street driven a tru-trac is a good choice too. Too many weak spots to invest good money on a factory limited slip. Got one use it but don't put any money into it.
 

Quick & Dirty

Sr. Member
Joined
Feb 15, 2004
Messages
826
I was looking into this, as I have a busted 31 spline LS, and wanted to swap the side gears into a good 28 spline case.

The 31 spline case has a 1.35" bore through the bearing stub, the 28 spline has a 1.25" bore. They are both the 3.062" carrier bearing size. The 28 spline case would have to be opened up to fit 31 spline axles. If you have to pay someone to do the lathe work, it's probably not worth it over a replacement carrier.
 

bronconut73

Bronco Guru
Joined
Aug 7, 2012
Messages
9,916
Mine fit. I assume it was a stock diff. Original and only other owner was the Jax. Elec. Auth..
Ended up selling my chunk to a Mustang guy.
I upgraded to a Detroit.
To the original poster....the boys are telling you not to invest to much into the stock carrier...and they are right.
So unless you are coming by all this stuff really cheap you would prolly be miles and money ahead buying a used Detroit.
I bought a used Detroit from Nine Inch Nodular on eBay over 10 years ago, still perfect.
 
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jmangi62

jmangi62

Bronco Guru
Joined
Jul 28, 2013
Messages
2,469
if mostly street driven a tru-trac is a good choice too. Too many weak spots to invest good money on a factory limited slip. Got one use it but don't put any money into it.

^^^^^ Thanks, great advise and will do. Jim :cool:
 

SteveL

Huge chevy guy
Joined
Jun 24, 2001
Messages
11,613
Loc.
Hawthorne ca
If it mostly street driven I doubt you'll like a detroit. True track is a good ls option otherwise skip the full time lockers and spend the extra $$for an arb.
 

bronconut73

Bronco Guru
Joined
Aug 7, 2012
Messages
9,916
Tru-Tracs are smooth. If you can keep both tires on the ground they are tough to beat.

Everyone says how bad mannered the Detroit is on the street, but I wanted one anyway.
I can genuinely promise you that once you get used to them you subconsciously do all the right stuff, like not accelerating through a turn too hard, easy on the throttle at the right times, etc...its like the muscle memory guitarist talk about.
I absolutely do not notice my locker anymore on the street. For most of my regular off roading it allows me to leave my eb in 2 wheel drive most of the time.

The theme of this story is that a locker is awesome off road and only quirky on road until you get used to it.

Disclaimer is if you live in an area of icy roads then a locker "can be" problematic on the street. My buddy Rob who also has a rear locker will often run on the front axle only (open) on icy roads. He says it is seamless and after awhile you forget you are only running on the front axle.
 

DirtDonk

Contributor
Bronco Guru
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Nov 3, 2003
Messages
47,355
Yeah, I'm not a nervous driver by any description normally. But I'm definitely going to be careful if I ever get mine into anything even remotely resembling slippery road conditions.
Unlike my previous Detroit experiences though, this current one is practically invisible on the street. Never driven one so smooth and non-reactive during normal driving conditions.

But I'm still not going to let my guard down.;)
And can't wait to get it off road someday.

Paul
 
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