My rig will shift into 4high no problem. However it will not shift back into 2wd. The "front wheel lamps" on the dash board will blink.

To finish the shift I must stop. Engage reverse and back up a 25 ft or so.

Is this normal?

Finally, I also experience much difficulty engaging low and locked low range.

I also am unable to use the rear diff locker.

All this while experimenting in the recent snow.

On my old 87 Jeep Wagoneer (wood paneling anyone?), vacuum actuators would need cleaning and vacuum lines cracked... What might need attenton on the SR, any common failure points I should look at?

Thanks!

First thing I'd try is to keep cycling the systems. They may not have been used much and will appreciate being cycled through all the settings.

Locker will only engage in 4LLC and at under, I think, 5 mph. Are you hearing the compressor under the passenger side rear seat kicking on when you hit the switch?

John B.

cycle it like johnny said it probably hasn't been used and when shifting into low you have to push down and forward.

It will be hard to shift into 4LLC with the tranny in gear and/or strain on the driveline. Try the shift on level ground in N, or at a very slow roll.

Re rear diff lock, how did you "check" it? Put the rear wheels on snow/ice unlocked and confirm that only one rear wheel spins. Now lock it (IIRC, it locks in 4HLC and 4LLC) and repeat the test. Both rear wheels should spin evenly.

I often get the flashing lights when shifting back to 2wd from 4H (non-locked). I generally shift the trans to neutral, then shift the t-case to 2wd, then engage the trans again. Blinking stops. If it continues, there is a whole troubleshooting process you can go through, which will solve your problem. It was posted here in the last few weeks, with pics! <img src="/forums/images/graemlins/kewl.gif" alt="" />

Also when shifting back to 2WD just backing off the throttle so the engine pulls a stronger vacuum may be needed. Where you reverse the rig gets a few cycles of throttle/ vacuum more so than any action on the driveline.
I find the system can take quite a few second and much longer when cold out to release the front drive.

It's interesting too how it can vary how long it takes to change the "displayed status."

The lights are controlled by an electronic gizmo that compares the primary VSS signal with the 4wd VSS signal, the latter usually being on the back end of the front output shaft. If you aren't moving, the light will stay on forever, because there's no diff in the signal. If there no diff in the signal, the front lights are lit, diff in signal, the lights go out, and in some late models, if there's any front drive signal, the lights stay lit.

Thanks guys. I will try these suggestions. I may be shifting from 4wd into 2wd, with the lights still blinking, but I don't feel it shifting.

I think the lights blink when it is in limbo between when it gets the signal to shift and when it has actually accomplished the shift.

Phil, got a link or title for that troubleshooting guide? I don't see it.

South SF Bay should get together sometime soon!

THANKS Guys!! <img src="/forums/images/graemlins/cheers.gif" alt="" /> <img src="/forums/images/graemlins/kewl.gif" alt="" />

If you plan it, we will (ok... "might") come. <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" />