Eaton selectable e-locker. That's about it. Any full-time locker (spool) or automatic part-time locking diff (limited slip) will probably play hell with the Stabilitrac. I'm guessin the computer needs full un-limited slip for the numerous electronic traction devices to function correctly when the t-case is in 4HI-Street mode. That's the hunch I have, and I keep waiting for somebody to prove or dis-prove this. Anybody care to weld-up the spider gears in a stock AAM-7 and go for a drive? Probably not a good idea. Here's why I think so...
The factory rear e-locker on ALL H3's only works in 4LO-Lock. Oddly enough, Stabilitrac is defeated in 4LO-Lock. In 2009 a front e-locker was added as an option. Its interesting to note that the front can only be activated AFTER the rear e-locker is engaged...which can only happen in 4LO-Lock mode. So the front e-locker is like a secondary level of "lock" that can only be used if the first level of "lock" (the rear) doesn't get you out of a jamb. The front cannot be activated by itself...not sure why. Both lockers will be defeated the second you shift out of 4LO-Lock...and as suspected, Stabilitrac is re-activated at the same time. Long story short...Never does the H3 allow Stabilitrac and Lockers to be used at the same time. I think this bizarre wiring scheme is a clue to the sensitivity of the H3's sensors and traction systems. Another clue is that other GM trucks use an automatic Gov-Lok unit in the rear...while the H3 has the electric locker, that operates as a single track when its not activated. When you look at all these characteristics...there must be a reason the H3 comes with e-lockers instead of posi-type units. I think it has to do with the Stabiltrac. I think any cross connection of axle shafts in 4HI-Street mode will confuse the Stabilitrac. The computer needs absolute un-restricted, free-spinning, wheels at all four corners to work properly. Any automatic locker will have some limit to its slip...some resistance...and that's the problem.
I know a couple people have re-wired their factory e-lockers to work in all t-case modes. Not sure how well that works with the Stabilitrac. I have an add-on front e-locker and I rarely use it. It's wired completely separate from any over-rides and I can turn it on at any time. I have not got the nerve to see what happens if I just locked it and drove around in 4HI-Street mode. I would probably get some Stabilitrac freak-out on the first corner I turned.
