Truck is still new to me, so I'm still checking on all the systems as I learn from this forum. I think I have a good understanding of how the SOTF system works. This is what I checked today:

Engine off, switch in 2WD, truck has been sitting w/o being started overnight. The drivers side half shaft is locked to the wheel (cannot be rotated). The passenger side can be rotated easily = the IWE is not locking in when the engine is off.

Engine on and SOTF switch in 2WD, both half shafts can be rotated independent of the wheels = correct operation.

Engine on SOTF switch in 4HI or 4LOW, both half shafts are locked to the wheels = correct operation.

All 4 wheels were on the ground for all tests. Shifting into neutral made no difference.

So the only problem I see is that the passenger side IWE is not locking with the engine off as it should. I did rotate the shaft to see if that would allow it to lock with the engine off, but it did not. Does this indicate a problem with the passenger side IWE or the vacuum solenoid? I suppose the next step is to pull the vacuum lines at the hub to see if vacuum is present when the engine is off.

 

Sounds to me like the Iwe is working just fine. The truck sat all nite so there was no vacumn to hod the Iwe back from the wheel but as sooon as you started it it moved freely. Sounds good to me.

 

Your IWE's unlock with vacuum. So when the truck is shut off, your IWE's will lock, then unlock when you fire the truck up. (Many folks think it's the other way around.) So you may have an IWE on the way out.

 

iwe's easily tested with a vacum pump available at just about any auto parts store...really dont cost much....$20.00 or so. well worth the investment to take out all the guess work..

 

The driver side works that way, but the passenger side doesn't. That's the problem.