Went outside again to double-check. Again, here were the results:

Rear isn't locking up. Confirmed my suspicion today in the dirt. I was hoping it was just the rear detection switch, but it wasn't.

1) Connected hand pump's gauge to rear diff pump outlet (at the end of the hose that connects to the diff). Perfect 5psi coming from the pump.

2) Removed rear diff detection switch, checked with multimeter...checks out OK. (ps...why does it say I have to remove the differential to take this switch out? What does the end of the pin connect to? I was able to get it back in by rotating the rear tire a bit until it felt like it lined up and wasn't hitting anything...).

3) Applied 5psi via hand pump directly to rear diff inlet. Wheels feel like they "lock" more firmly together when the pressure is applied, but they still turn the *opposite* direction.

4) Lost 0.5psi in about 120 seconds of turning the wheels and watching the gauge...the needle moves slightly as I would turn the tire back and forth (lock to lock...it was in park), but it doesn't seem to be a leaker. The pump does not run very long (only a couple seconds), and I don't hear any air leaking out of the breather.

If it's not the actuator in the diff...what part could it be, mechanically, that it's taking in the proper amount of pressure but not locking up? The car runs and drives just fine, with no noise or slop from the rear end. I also changed the rear diff oil less than 2 weeks ago, and it was perfectly clean with no sign of any broken metal bits or shavings inside. I have to get this locker working for a trip coming up - I'll really be hurting without it! <img src="/forums/images/graemlins/scared.gif" alt="" />