I just completed the installation of a cast iron front differential with an Eaton e-locker. Here is the way my car was set up prior to starting this project.

Hummer 2006 H3, Adventure Package including the 4:1 transfer case and rear locker, manual transmission, leather interior, navigation, Rancho 4” suspension lift, Pro Comp Xtreme 17x8 black wheels with Gorilla spline black lug nuts, Pro Comp 35x12.50R17 Xtreme all terrain tires, Gobi roof rack with HID lights on all sides, Volant cold air intake, and Gibson cat back single exit exhaust with removable chrome tip, Hummer rock sliders with removable steps, Hunner leaf spring skid plates, SMC grill guard, PCMforLess computer upgrade, DeFelice hidden winch mount, T-Max 9000 lb competition winch with remote control and 60’ of synthetic line, Warrior Products 6” leaf spring shackles, Custom center console switch control panel, Custom engine compartment exhaust fans, Optima Yellow top battery.

 

My vehicle had a stock aluminum front differential housing with 4.56:1 gears and no e-locker. The goal of this project was to upgrade my front axle from a non-locking differential to a locking differential, staying as close to factory original as possible.

I purchased a complete used front cast iron differential assembly with 4.10:1 gears from a 2009 Hummer H3 Alpha Adventure Package with auto transmission. I purchased a set of ring and pinion gears to upgrade the new differential from the 4.10:1 gear set to the 4.56:1 gear set. I actually considered larger 4.88:1 gears to compensate for my 35” tires (because I’d like to go to 37”). Although the rear housing is large enough to accept 4.88:1 gears the front housing is not.

I purchased the carrier brackets and intermediate shaft housing, so that I wouldn’t have to cannibalize my existing front differential. I also purchased the new stronger half shafts, thinking I shouldn’t do the build without them. After a lot of worry and investigation, I purchased the Eaton e-locker carrier with magnetic actuator ring from a local GM Hummer dealer. Be careful, there are a lot of part numbers for this item and only one of them is what you want. It’s best to have a VIN number from a 2009 Hummer H3 to “verify” that you’re ordering the correct part, because it isn’t returnable.

I delivered the cast iron housing, Eaton e-locker, and ring and pinion gears to a local gear shop. They asked me to determine where to drill the access hole for the wiring, which required more investigation. I found a 2009 H3 with the front e-locker, crawled underneath, and memorized its location. The magnetic actuator has a small tab that needs to be engaged somehow. This tab keeps the actuator from rotating more than a few degrees, which prevents stress on the wiring. Presumably a housing with an e-locker would have something to engage this tab, but this housing doesn’t have anything. We decided to weld a small forked clip to the bearing cap that engages the tab to keep the actuator from rotating.

I picked up the assembled front differential and a small box with the left over parts. They used new bearings for the carrier, but otherwise used the existing bearings and seals, as they were “as good as new”.

 

Day 1 – I recorded various data for comparison of the two differentials. Then I placed the truck on a pair of jack stands, removed the front wheels and tires, and completely relaxed the torsion bars. I started removing and disconnecting the various suspension components related to removing the old differential. Removing the disk brake rotors from the hubs and then removing the hubs from the steering knuckles was very difficult, because of rust. I used some penetrating oil (as seen on TV) that actually worked fairly well, although it’s a brand that I haven’t seen before. Eventually I had the differential loose and ready to come out, but I struggled to remove the housing and CV axles as a unit, and I finally decided that it wasn’t going to work.

Day 2 – I disconnected the driver side steering knuckle lower ball joint, to give myself more room, and eventually was able to maneuver the old differential with both CV axles to the ground. I struggled a bit with the new differential, partly because I couldn’t keep it on the floor jack. It was difficult to lift, rotate, and slide left and right by myself. I’m sure it would have been much easier to install without either CV axle, but at this point I didn’t want to remove the passenger side steering knuckle. I installed the housing with the passenger side CV axle and the driver side axle tube, and then inserted the driver side CV axle after it was hanging in place. I began installing and connecting the various suspension components in reverse order from day 1.

Day 3 – I invested some time cleaning up the rust problems related to the disk brake rotors and the hubs, and finished installing and connecting the various suspension components. Obviously it’s important to have the correct torque information and proper tools to do the job. I adjusted the torsion bars for the original ride height, installed the front wheels and tires and removed the jack stands. The torsion bars were re-adjusted to compensate for the additional weight. I also recorded more data for comparison of the two differentials.

Day 4 – I’m running it as a standard open differential, listening and feeling for trouble. Although I’m confident that all is well, I’d prefer to detect something now rather than on my next trip. My next project is to get it wired up so that I can lock and unlock it on demand. Once I’ve had a chance to do some serious off road tests I’ll add to this post.

 

Lesson 1 – It is probably best to remove both driver and passenger side steering knuckles, and then both axles. However, if I do this again I will disconnect the passenger side steering knuckle lower ball joint, and not the driver side. Once the passenger side steering knuckle is swung out of the way, I’ll remove the passenger side CV axle. It does (in fact) just pull out of the differential housing (give it a strong jerk). Once it’s out, it should be fairly easy to lower the differential housing down and slide it towards the passenger side, extracting the driver side axle tube and CV axle as you go. Let me know if you try this!

Lesson 2 – When I started this project there weren’t any options. I wanted a locker in the front of my H3 that was as close to factory original as possible, and I decided to build my own. I used various sources in the process of collecting the parts for my project, one of which goes by the name of TheBroken. Although his parts weren’t always packed perfectly, they did arrive in good condition and were as advertised (like new). I would recommend him highly and use him again. You can reach him by email at offroadtech@gmail.com, and his web site is now offering two locker options for the H3 which, at least for now, may be a better option. Check them out!

Lesson 3 – It is probably best not to do this when the kids are on spring break and out of school. Over the course of the three days, I spent about 18 hours working on the car, and the rest of the time helping the grandkids. We made things out of wood and schedule 40 PVC, and went to lunch (kids choice) with family and friends. Actually, it was time well spent!

Lesson 4 – Other than the standard “back yard mechanic” issues, the CI front differential is a “bolt in”. There are no fitment issues, clearance adjustments, or compromises required. Unlike some of those reality shows on TV, it’s OK to “try this at home”. I don’t have a lock on this, but I do have some experience and I’m willing to share it with anyone.

 

sounds complicated, good job on giving us a description

 

Where did you get all your stuff from?

 

I bought the CI housing (via a local gear shop) from an "online parts source", the Eaton locker came from the dealership, and the rest of it came from you. Collecting all of the parts took about 60 days, and having it assembled into one unit took about 10 days.

In the end I am recommending that anyone interested in "trying this at home" contact TheBroken. He has the parts and was helpful during my project. His website has ready built units available that are ready to bolt in.

 

Sorry didnt know that was you. Thanks!