4WD LOW question

[mbaessler]

I have a 99 EXPY 5.4L EB.
I was having Safelite change out my windshield in my driveway. When I got into my truck to put it back into the garage. I noticed it was vibrating and shaking as I was turning the truck to put it back in the garage. Then I noticed the windshield guy must of hit my knob and placed it in 4WD low. I put it back to AWD and everything was normal. I know you are not supposed to put the truck into 4WD low on pavement, which of course caused all the vibration. The question I had. It was only in 4WD low about 50feet before I figured out what was going on. No way I damaged anything is there.
Mike

 

[greasemonger]

Not likely anything was damaged but it still shouldn't have been shaking. If you don't mind me asking, why not drive in 2hi instead of awd? I make sure to cycle through the 4wd regularly, off pavement, but my experience says that unless you went 50 feet at 50 mph you should be fine. I wonder if in the turn the l/s (assuming you have it) was engaging like a locker.

 

[bedrck46]

the 99 does not have the 2wd option like the 97/98 expy's have unless you pull a fuse or do the brown wire mod

 

[toms89]

Not likely anything was damaged but it still shouldn't have been shaking. If you don't mind me asking, why not drive in 2hi instead of awd? I make sure to cycle through the 4wd regularly, off pavement, but my experience says that unless you went 50 feet at 50 mph you should be fine. I wonder if in the turn the l/s (assuming you have it) was engaging like a locker.

What bedrck46 said is correct.

The tighter you turn with 4wd engaged it becomes increasingly noticable as something has to give. Either the tires on pavement or the clutch in the transfer case must slip. Tires slip in my case. I have experienced the same as the O.P.

I agree. Unlikely anything was damaged. Just don't make a habit of it. Puts a lot of stress (torque) on the drivetrain. It behaves the same in 4 high or 4 low on high traction surface.

 

[greasemonger]

the 99 does not have the 2wd option like the 97/98 expy's have unless you pull a fuse or do the brown wire mod

Ah very good. Learning about these things daily. All these fancy electronics are worlds apart from my wrenching experience with broncos.

 

[bedrck46]

Ah very good. Learning about these things daily. All these fancy electronics are worlds apart from my wrenching experience with broncos.

Totally agree Its always a good day when I learn something new.