Ford 8.8 Eaton eLocker build and install

[TowVan]

Awesome work sir!
I've managed to avoid any differential work so far, but thanks for the conformation of the GM/8.8 similarities!

[dit]

I realized that I posted this previously elsewhere. This is some information that might be useful. Probably should be up top but I don't know how to put it there!

Years ago when I put the 4.10 gears in my van, I wanted to also install a selectable locker. Of course there wasn't one available for our 7.5" rear ends and still isn't. Living in snow country I really didn't want an auto locker so I opted for a TruTrac.

Well let's just say that the TruTrac while good, it really doesn't help much in corner to corner unweighting that is so common off road. Now that I have a bad axle, wheel bearing and leaky seal I'm reconsidering a selectable locker in a Ford 8.8. There is a lot of talk here about Ford 9" which are rather obsolete. The 8.8's are very common and used under a wide variety of vehicles. In researching both on the web and at my local salvage yard I have discovered that most 8.8's, like our diffs, have a passenger side offset.

About 8.8s

The diff I'm looking at is from an f150 4x4. It has a WMS (wheel mount surface) width of 65" compared to an Astro 66.25. Drivers side from center 33.5 (Astro 35.25), Passenger from center 31.5 (Astro 31), spring perch 45 (astro 50).

Axle tube centerline to u-joint ~12" (same as Astro)

My thoughts are to mount the rearend .25 to .5" left. This will make the passenger side correct or .25 long. On the drivers side install a 1.25" wheel adapter. A little Frankenstein I know, but super simple. I know off road guys run the spacer/adapters regularly with no issue so I'm not worried about that.

The only real fabrication will be spring perches, shock mounts and turning (on a lathe) the passenger axle hub to fit the GM center bore and re-drilling the same axle (and drum) for the 5 on 5" lugs (the drivers side lug pattern will be corrected by the adapter/spacer.

Then install 4.10s on an Eaton eLocker.

BTW, I also measured up Explorers (way to narrow) and a 1/2 ton Econoline 8.8: ~68.5 wide (36.5 x 32). The wheels were on so don't quote me on that measurement. So with a lot of fabrication and after market axles that rearend would work; or go with a 2.25" wider stance.

[sixsix]

Nice work- gotta' want that real bad... Cool.
Man after MY own heart.

[dit]

Nice work- gotta' want that real bad... Cool.
Man after MY own heart.

Ya the fun is in the fabrication! But beyond that. From my experience, the difference between a locked and open differential is about the same as that between 2wd and 4wd; less getting out to stack rocks, less tearing up the trails. I hope this works out should I ever receive delivery of the locker.

[SainT]

I also wanted thicker axle with reliable lockers on second hand market
So I bought 4.11 nissan patrol y61 rear axle with LSD 233mm(9.17) for 100$ -they have plenty of cheap oem lockers and ratios and have 6x139.7 (5.5) lugs +disk brakes
The main reason to choose this axle - wheel bearings are bolted by nut to half shafts -if I break shaft -the wheel won't go outside

[WERDI Recreation]

Years ago when I put the 4.10 gears in my van, I wanted to also install a selectable locker. Of course there wasn't one available for our 7.5" rear ends and still isn't. Living in snow country I really didn't want an auto locker so I opted for a TruTrac.

If I follow you correctly the ARB company makes an air locker for the 7.5 rear end on gm's. S10, Astro Safari, Blazer...

Unless the "selectable" actually refers to electric locker.
ARB RD148 is the part #

J.

[Sparkydog]

Other potential Ford 8.8 donors with posi are Aerostars and Mustang V8's. Both of these axles do not have perches for leaf springs but since you need to relo the perches anyway...

The Aerostar 8.8 axles were attached to a 3-link so the pumpkin has a weird "horn" off to one side. But easy to cut off. Almost nobody in a wrecking yard is wandering in the Aerostar section looking to raid them for 8.8 posi's (except me).

[CopperFiremist]

Most Aerostars are LONG GONE

[AstroWill]

Years ago when I put the 4.10 gears in my van, I wanted to also install a selectable locker. Of course there wasn't one available for our 7.5" rear ends and still isn't. Living in snow country I really didn't want an auto locker so I opted for a TruTrac.

If I follow you correctly the ARB company makes an air locker for the 7.5 rear end on gm's. S10, Astro Safari, Blazer...

Unless the "selectable" actually refers to electric locker.
ARB RD148 is the part #

J.

From my understanding the ARB RD148 is for the 7.625 IFS front differential, carrier would be different and so it would not fit.

[WERDI Recreation]

Years ago when I put the 4.10 gears in my van, I wanted to also install a selectable locker. Of course there wasn't one available for our 7.5" rear ends and still isn't. Living in snow country I really didn't want an auto locker so I opted for a TruTrac.

If I follow you correctly the ARB company makes an air locker for the 7.5 rear end on gm's. S10, Astro Safari, Blazer...

Unless the "selectable" actually refers to electric locker.
ARB RD148 is the part #

J.

From my understanding the ARB RD148 is for the 7.625 IFS front differential, carrier would be different and so it would not fit.

AstroWill thank you for that. I am glad you pointed that out.

[WERDI Recreation]

Years ago when I put the 4.10 gears in my van, I wanted to also install a selectable locker. Of course there wasn't one available for our 7.5" rear ends and still isn't. Living in snow country I really didn't want an auto locker so I opted for a TruTrac.

If I follow you correctly the ARB company makes an air locker for the 7.5 rear end on gm's. S10, Astro Safari, Blazer...

Unless the "selectable" actually refers to electric locker.
ARB RD148 is the part #

J.

From my understanding the ARB RD148 is for the 7.625 IFS front differential, carrier would be different and so it would not fit.

https://www.drivetrainshop.com/ARB_Air_Locker_p/arb-rd148.htm ARB RD148 Compatibility
Just click on compatibility and it reveals the possible applications

[AstroWill]

Call ARB directly, I'm sure they will easily clarify it. I rarely trust 3rd party parts compatibility charts.