Junk Yard E-Locker from a Hummer H3

[Bo Duke]

This is partly technical, partly bench racing discussion. The topic: Repurposing e-lockers from modern vehicles.

The question- Has anyone used a Hummer H3 factory rear e-locker in a front 10 bolt axle application?

I’m building a mild adventure rig out of my 1990 Jimmy for hauling the family around in the mountains. I plan to run 35” tires and want to keep it looking mostly stock, with factory 6 lug wheels. For easy parts availability anywhere in the country my overall goal is using factory parts, specifically junk yard stuff when possible to keep the cost down (and for the pure fun of tracking down parts and building stuff on a budget). Of course it’d be easier to just order new stuff and drop it off a shop to be built, or just buy CUCV 1 tons. But that’s not really my goal at this time. I already have a Jeep on tons and 40's for hard core stuff.

The H3 rear axles are all over salvage yards for $250-400 with the e-locker and 4.56 gears (if you want to run used gears, but that’s another topic).

On paper it works- the H3 has a 10 bolt rear axle with 30 spline shafts, the same as my front axle in my 1990 Jimmy. I believe that locker would drop in to my front 10 bolt correct? Aside from wire harness routing through the diff, any other issues I might run in to? If the H3 e-locker was designed as a rear application with 33 inch tires, then it should surely hold up in the front, right?

Try to keep this thread on track, I'm not looking for other locker suggestions. I have zero interest in an ARB (I don’t want air lines or air leaks) and I’m not looking at full time lockers (power trax or detroit) right now. My goal is an e-locker for easy on/off and great street driving, and keep axle shafts alive for as long as possible. I know someone will say something about detroits are no problem on the street; I know, I have plenty of experience with them. I’ve driven Jeeps with front/rear detroits on the street and offroad for 20 years.

For the rear axle I have a six lug semi float 14 bolt. It’s loaded with 4.56’s and an eaton e-locker. I gave $100 for the 1980’s truck axle, geared and locked with 8 lug shafts. I paid another $150 for a 6 lug axle, and used the shafts and brake backing plates and to covert the 1980’s axle to 6 lug, and bolt it in to the K5. So that's the junk yard/used parts spirit I'm going for here.

And a pictures of the rig, because everyone likes pics.

 

[ktmoutfront]

Do it and let us know how it works.

 

[dyeager535]

On paper it works- the H3 has a 10 bolt rear axle with 30 spline shafts, the same as my front axle in my 1990 Jimmy. I believe that locker would drop in to my front 10 bolt correct? Aside from wire harness routing through the diff, any other issues I might run in to? If the H3 e-locker was designed as a rear application with 33 inch tires, then it should surely hold up in the front, right?

Not trying to take it off track, and as you know with the rear, you aren't supposed to use the e-locker "on the fly".

Maybe it's only me, but I tend to run 2WD as long as I can, so that I know when I'm getting into conditions that are going to eventually overcome the traction I have available. E-locker is a good option, I do like the on/off control, and that it's electrical and not air or strictly mechanical, I just didn't like the idea of not being able to shift while moving.

Also seems like they would be real hard on the front axleshafts (edit: no harder than any other "real" locker, didn't mean to imply otherwise, was thinking vs. limited slip, true trac, etc), unless you made darn sure to avoid any situations where the front axle had good traction on both sides.

I haven't pulled the trigger on one, but the true trac for me came down to being about the best compromise. Of course, even those people talk about breaking axleshafts with, so that would make me hesitate even more on the e-locker.

I didn't realize they could be had so cheap in the wrecking yards though, hard to beat that cost. True trac alone is something like $550, and you have to get eatons bearings for it as well.

 

[Bo Duke]

Do it and let us know how it works.

I was hoping for at least a "yeah, that seems like it should work" before I spend the time and money lol

Not trying to take it off track, and as you know with the rear, you aren't supposed to use the e-locker "on the fly".

I haven't pulled the trigger on one, but the true trac for me came down to being about the best compromise. Of course, even those people talk about breaking axleshafts with, so that would make me hesitate even more on the e-locker.

I didn't realize they could be had so cheap in the wrecking yards though, hard to beat that cost. True trac alone is something like $550, and you have to get eatons bearings for it as well.

Correct, can't lock on the fly, similar to all other selectable lockers- you're just asking to break stuff if things are spinning and you lock up a diff. I have no issue with stopping on a rock ledge to engage the locker before continuing to crawl up it. Though my concern for breaking shafts is pretty low with the type of wheeling I have planned for this rig. I'm familiar with true tracs, but have no interest in spending money on one. If I'm going to spend any real coin on a locker, it's not going to be for a 10 bolt lol.

 

[frankin5]

8.6" carrier will will fit in an 8.5" housing if you use special carrier bearing. I have 8.6 Detroit truetrac's front and rear. You just can't put an 8.5 in the 8.6 housing. They use the same ring and pinion.

 

[6872xtc]

I would be interested in trying what you are talking about. I liked several factors of the 6 lug 14SF axle that I ran for a bit. The E-locker seems like a feasible option when you need extra traction occasionally. The only drawback that I read about was about it doing an unlock, then re-lock cycle when changing directions. I don't know if that is true, nor do I know if it would be a noticeable problem in some terrain. You would have to be the judge of that, in my mind, as you know your driving style and what conditions you are in the most.

 

[Bo Duke]

8.6" carrier will will fit in an 8.5" housing if you use special carrier bearing. I have 8.6 Detroit truetrac's front and rear. You just can't put an 8.5 in the 8.6 housing. They use the same ring and pinion.

Good info here. I'll look into the 8.6 bearings.
Is there any issue with using a locker made for a rear c-clip axle in a front axle application, and axle shaft engagement into the diff? I can't picture any issues.

The only drawback that I read about was about it doing an unlock, then re-lock cycle when changing directions. I don't know if that is true, nor do I know if it would be a noticeable problem in some terrain. .

You're correct, they do disengage. I wouldn't use one for hard core off roading either. Here's a video that shows an example of how they work, at the 1:50 mark.

Hummer H2s have a semi float 14 with an elocker and disc brakes too, if you want 8 lug. They're really wide though, and there's no way to convert it to 6 lug.

 

[dyeager535]

That video led me to this one, which is apparently well after the above video. They show some pretty disturbing behavior from the e-locker.

Not trying to sway opinion, it was just new to me, never heard of any real issues before this. Kind of find it hard to believe it's not an electrical issue in this video, I don't understand how it wouldn't work if there was power to the unit. It certainly shouldn't be a variable thing, either its on or its off.

Definitely tempted to get a front and rear e-locker out of the yards in case I change my mind on the gov-lock/true trac

 

[centexk5]

It may also be programmed that way through the computer. GM might have it setup to do that. Running it straight through a switch might make it behave differently.

 

[dyeager535]

It may also be programmed that way through the computer. GM might have it setup to do that. Running it straight through a switch might make it behave differently.

Maybe I'm not understanding what you are saying, but in the "problem" video, they ARE run through a switch, as far as I can tell those are retrofits (edit: reading the comments, they apparently were all installed by "experts" and they have 6 that don't work, two of which destroyed the axle). Being an electro-magnet setup, I just don't get how the locker could stay unlocked when it has power (since it unlocks then locks changing direction), unless that cam mechanism is binding up somehow.

Again, not trying to detract from the OP's thread, just adding info that I stumbled across due to this post.

 

[6.2Blazer]

I don't understand why an e-locker would be any harder on the front shafts then any other type of full locker. A 10-bolt front with reasonable size tires, and a reasonable driver behind the gas pedal, will hold up pretty good. I also don't understand some people's view of not wanting to engage the front locker because it might break an axle shaft??? Sure, it puts more stress on a shaft and the worse situation is when one tire has zero traction (in the air) and the other is wedged down in a rut....but isn't that the entire purpose of having a locker to begin with. I have seen a Jeep guy with an ARB in the front Dana 30 that wouldn't engine the front locker on tough obstacles because of being afraid of breaking shafts, then sat there and watch him beat on the rig way harder trying to get up the obstacle with an open diff and he wound up breaking other parts several times.

Anyway, back to the OP if you could pick up the entire rear axle for that price it would be worth taking a chance on it. It's been discussed above but I would have questions on bearing sizes and stuff but sounds like it could be made to work. I also think it could be made to run off a simple switch and bypass the ECM without any issue. Generally bypassing all of the ECM controls is not an issue on this type of stuff when retrofitting them into older vehicles. The problem isn't the on/off switch control, but sometimes when you bypass all of the ECM and programming on the vehicle they originally came in it freaks out the ECM.

 

[dyeager535]

I don't understand why an e-locker would be any harder on the front shafts then any other type of full locker.

It wouldn't be, just harder on them than a traction aid that allows independent axle rotation. Which in those products, also means traction isn't as good or as consistent. But steering will be easier. Pluses and minuses, just comes down to individual preference and need.

 

[Blue85]

Great idea. I was not aware of this H3 rear end. I did the same thing, buying a whole H2 rear just to transplant the e-locker in my 14Bs/f. There is an anti-rotation thing required to keep the coil from spinning with the diff (which would eventually break off the wires) and it transferred directly from the H2 axle to square body axle. The only other mod was drilling a hole for the wire grommet. https://ck5.com/forums/threads/14sf-tech-info.135125/page-5#post-3973772

Anybody know a part number for this carrier bearing that lets an 8.6 diff go in an 8.5 housing? Sounds like it's not the bearings that come in either axle. Obviously this will require 30-spline shafts. IIRC the only mod required to fit 30-spline shafts in a 28-spline housing was to enlarge the openings in the carrier - which won't be required here.

 

[centexk5]

Maybe I'm not understanding what you are saying, but in the "problem" video, they ARE run through a switch, as far as I can tell those are retrofits (edit: reading the comments, they apparently were all installed by "experts" and they have 6 that don't work, two of which destroyed the axle). Being an electro-magnet setup, I just don't get how the locker could stay unlocked when it has power (since it unlocks then locks changing direction), unless that cam mechanism is binding up somehow.

Again, not trying to detract from the OP's thread, just adding info that I stumbled across due to this post.

That's what I get for posting before coffee.

 

[6.2Blazer]

It wouldn't be, just harder on them than a traction aid that allows independent axle rotation. Which in those products, also means traction isn't as good or as consistent. But steering will be easier. Pluses and minuses, just comes down to individual preference and need.

I was being a little sarcastic on my question, and it was based on a previous comment talking about how an e-locker was harder on shafts. Ironically I've broken more front shafts with a limited slip versus a locker. Think it goes back having to give the truck more throttle and hit things harder to make it, and the power transfer not being as consistent from side to side. I would never consider turning off a locker on a hard obstacle but that's my opinion. My opinion is also if you are afraid of a locker breaking something than you really don't need it.......the whole concept of "I need a locker....but won't engage it on hard obstacles" simply doesn't make any sense to me. Same goes for staying in 2wd on a trail until you are stuck. Guess a lot depends on what you deem to be a trail or what you deem to be fourwheeling. If it's a simple requirement to get between point A and point B for a job or to your house and there is a mudhole or snow I can understand it a little, but personally when I go fourwheeling a trail that you can traverse in 2wd is pretty boring. I've also seen several people get stuck in 2wd and by then it's too late for 4wd to help them because they have lost momentum and dug in.

 

[Bo Duke]

Anybody know a part number for this carrier bearing that lets an 8.6 diff go in an 8.5 housing? Sounds like it's not the bearings that come in either axle. Obviously this will require 30-spline shafts. IIRC the only mod required to fit 30-spline shafts in a 28-spline housing was to enlarge the openings in the carrier - which won't be required here.

Rock Auto shows the same part number for a Hummer and a Blazer/Jimmy "Differential Carrier Bearing" as LM501349. Maybe the it's the race that's different? Still searching for that, but probably won't get around to it until tomorrow at this point.

 

[frankin5]

The 8.6 has a larger carrier bearing diameter than the 8.5. The inner diameter of both bearing are the same, the outer is different.

 

[Blue85]

So you can just re-use the 8.5 bearings?

 

[black dawg]

I recently did a tru track in a front 30 spline 10 bolt. The carrier was listed as 8.6 and required bearings lm102949 and races lm102911. for install in pre 99 10 bolts.

 

[Bo Duke]

I recently did a tru track in a front 30 spline 10 bolt. The carrier was listed as 8.6 and required bearings lm102949 and races lm102911. for install in pre 99 10 bolts.

Good info, thanks.