My 94SR AT will occasionally automatically engage the front diff and stick it in 4H without me doing anything. What is wrong?

It has to be something in the T-Case. The hubs are permanently engaged on your vehicle. It's called ActiveTrac. It may be a linkage issue (bent maybe), but I've never seen a vehicle "engage itself" into 4hi.

Actually, I'd bet it's just the front disconnect sticking. When vacuum isn't present, it will engage itself. I've had the lights flash on on mine but could get the disconnect to disengage by rocking the truck back & forth in gear to try and solve the problem. I'd check out the vacuum solenoid, lines, and actuator for leaks and also check out the actuator for built up gunk that might cause it to not disconnect easily.

<small>[ June 09, 2003, 09:30 AM: Message edited by: Lee N ]</small>

Lee N,

Thank you, I will check out the vacuum solenoid, lines, and actuator for leaks and also check out the actuator. I don't have Active-Trac. It is doing what you described.

</font><blockquote><font size="1" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">quote:</font><hr /><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">Originally posted by 94Monty:
<strong>Lee N,

Thank you, I will check out the vacuum solenoid, lines, and actuator for leaks and also check out the actuator. I don't have Active-Trac. It is doing what you described.</strong></font><hr /></blockquote><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">Actually, you do have Active-Trac. That is the ability to drive in 4 wheel drive on pavement as opposed to 4 hi lock. The Active-Trac (or SelecTrac in Australia) was installed in all Gen II's (1992-2000?) and allows shift on the fly. It uses a slip coupling on one front half shaft and a vacuum shift actuator to disconnect the front axle instead of using locking hubs on each wheel.

Lee N,

Thanks again, I didn't know I had Active-Trac. Since I didn't have one of those factory installed stickers in the rear window, I thought I just didn't have that option. Of course I have the manual but it wasn't specific.

Carl