Popping Noise When 4x4 Engaged---HELP

[1992 Eddie Bauer]

Hi guys, I'm new to this forum, but not new to mechanics and working on vehicles. But this is the first Explorer I've ever owned; it's a 92 Eddie Bauer. This is the first winter I've had it and when I tried to use the 4x4, it wouldn't engage. After reading an thread on here posted by Brian on how to fix the shift motor, I repaired it and it's working great. Now that the 4x4 is working, I drove it in the snow for the first time today. While driving it I noticed a "popping" noise coming from the front driver's side wheel area. There didn't seem to be a pattern that I could notice. The popping noise was random and would occur every now and then. The only thing I could recognize is that it would happen when the hubs were locked in. It would pop even when I shut the 4x4 off, but with the hubs still locked in. (from what I read on here, the way to unlock the hubs is to shut the 4x4 off and back the vehicle up and the hubs disengage). As you can tell this is the first time I've had a vehicle with automatic hubs and electronic 4x4. I have a 79 Bronco and the hubs and shifting in and out of 4x4 is done manually. So any advise on what could be making this "popping" noise would be much appreciated....Thanks.

 

[shaggymane]

Sounds like one of your auto lockers is all but gone. Maybe.

There are (3) reasons why the front hub may not engage the axle shaft and work:

1) There is to much grease or other crap in the hub to allow the splined collar to fully engage the splines on the axle shaft.

2) The washer (spacer) is missing behind the snap ring on the axle shaft allowing it to travel and disengage from the hub.

3) The internal components of the hub are broke.




for cleaning, See this thread http://www.explorerforum.com/forums/showthread.php?t=201782

This thread is loaded with links, diagrams and info
http://www.explorerforum.com/forums/showthread.php?t=232754

Here's another good write up especially at the bottom.
http://www.therangerstation.com/tech_library/HubDiagnosis.html

the one I like best is this one. I'd like to see someone try it before me.
http://www.explorerforum.com/Singleton/web/pages/autohubs.html

 

[shaggymane]

I know what else I want to add. I've got one that won't fully lock. Sounds like it's going through a detente. Backing up won't allow it to fully unlock. It'd make that whirring /ratcheting sound. So to be able to drive it with out doing more damage, I pulled the cam out. Splined thrust washer and C-clip back in.
Disclaimer: It worked for me. Do it at your own risk.

 

[1992 Eddie Bauer]

I know what else I want to add. I've got one that won't fully lock. Sounds like it's going through a detente. Backing up won't allow it to fully unlock. It'd make that whirring /ratcheting sound. So to be able to drive it with out doing more damage, I pulled the cam out. Splined thrust washer and C-clip back in.
Disclaimer: It worked for me. Do it at your own risk.

Hmm, well I haven't heard any ratcheting, buzzing or grinding sounds, just a popping noise like a u-joint or knuckle would make. I do know it was locking in 4 wheel drive, but I don't know if it was staying locked in or not. Could the popping noise be that it was locking and unlocking???

 

[shaggymane]

here's what I would do for more info. Get the front end in the air. tires only about an inch off the ground. Leave the T-fer in 2hi. Rotate the front drive shaft in the *forward direction* to lock in the hubs. jam a short 2x4 under the Pass tire to stop it from turning. See what I'm getting at? You want the half shaft on the drivers side turning.

turn the steering wheel completely one way. rotate the drivers tire in forward direction only. Listen for the popping. turn the steering wheel completely the other way. Again rotate tire forward only so it doesn't unlock.
If you don't hear the noise you're looking for, try the Pass side just in case. Those noises can be funny

On second thought, in addition to the above - after you get both locked in, block under the Pass tire, do unlock the drivers side, get under and rotate the front drive shaft again. That should make only the half shaft on the drivers side turn. Do the steering wheel thing both ways. That should isolate the half shaft, which is what i think you want to do - isolate components to find out where the noise is coming from.


If you can't get a good hold of the front drive shaft enlist the aid of a strap wrench or a pipe wrench