4x4 Issues

[foosh]

A couple of you know i have the 4x4 death plague currrently... I'm just looking for some med-mechanical opinions on it.

I don't have the time for the truck to be down more than a couple hours unless it goes to a shop. So the question is should i look at it myself or just send it in.

My best friend is a mechanic, and i'm no stranger to this stuff. I believe it the front dif, the switch is enguaging correctly, and the tcase you can hear working like normal...

Problem: intermitent 4x4. I turn the switch into 4wd and 4lo and it stays in 2wd. Everything is normal audibly the sound of the tcase enguaging, then nothing up front spins in mud. First thing i do when i get home is to put it up on jack stands put it in 4wd and shift through the tcase and see if it enguages that way. I know i had a small oil leak in the front diff, i just didn't think it was big enough or fast enough to do damage this quickly. Also while i was stuck this weekend at a couple points it all of a sudden would start working like nothing was wrong then unexpectidly shut down. Thats what i know so give me some help doc!


So was it colonell mustard with the revolver, or Miss peacock with the candle stick?

[Trail X]

You need to do more investigating before we can narrow the issue down.

My recommendation is to jack up one front wheel. Put the vehicle in 4WD. Try to spin the lifted front wheel. If it spins, check to see if it is spinning the front prop-shaft. If the front prop shaft is not spinning, then your issue is either in your front diff, or disconnect. Since you have intermittent 4WD, I doubt the issue is in your diff itself. If the prop shaft is spinning, then your issue is in your transfer case.

[The Roadie]

I've posted about a hundred times that there are two noises involved. But if you don't get a Service 4WD light, you probably don't have an electrical problem with the front axle actuator. But always be listening for BOTH sounds. The front axle actuator only whines on a mode transition from 2HI->A4WD and vice versa.

[foosh]

You need to do more investigating before we can narrow the issue down.

My recommendation is to jack up one front wheel. Put the vehicle in 4WD. Try to spin the lifted front wheel. If it spins, check to see if it is spinning the front prop-shaft. If the front prop shaft is not spinning, then your issue is either in your front diff, or disconnect. Since you have intermittent 4WD, I doubt the issue is in your diff itself. If the prop shaft is spinning, then your issue is in your transfer case.

Check out my first post in this thread, thats what I said I am going to do... your saying jack the whole truck up or just that tire. I was thinking about putting the whole thing up on stand and cycling through each stage of the tcase to see what enguaging or not enguaging.

So if I leave it off or in park in 4x4, and am able to spin the front wheel
1.) the front driveshaft spins its a transfercase issue
2.) the front driveshaft doesn't spin its a front differential issue

[Trail X]

If you jack up both front wheels, and turn only one of them, that won't necessarily make the prop shaft spin. The direction of least resistance will probably be through to the other wheel. By keeping one front wheel on the ground, you lock that wheel from moving, and thus the prop shaft must turn.

I doubt its a front diff problem. If it was, you'd hear grinding of some sort. If you have one tire that spins, and the prop shaft stays still while in 4HI, its most likely your disconnect (which is separate from the differential).

[foosh]

Ok so if thats the diagnosis, what do i do to fix it assuming its the disconnect?

[The Roadie]

Then you have to take it apart to see what broke... compnine is down at the moment so I can't post the exploded view.

[Trail X]

compnine is down at the moment so I can't post the exploded view.

Its also in the first post of my 4wd troubleshooting thread.

[foosh]

Wheel spun no driveshaft spin when i put it in gear the one rear spun and the front didn't, but the shaft spun