Grinding Sound from 4wd to 2wd

[capebruce]

On my 1992 Explorer :exp: , I have the electronic 4WD pushbutton. When going from 4WD to 2WD while driving very slowly, I will suddenly get an awful :thumbdwn: grinding noise after a few seconds. The only way to get rid of it is to put it back into 4WD. Any ideas of what is going on and is something about to fail? Thanks!

 

[Darrman]

Did you hit reverse to unlock the auto hubs?

 

[capebruce]

Thanks. That seemed to cure it. I repeated the pattern several times to see if I could put it in 4WD, stop the vehicle, put it into 2WD, reverse the Explorer for 50 feet or so, then drive forward with no grinding noise.

 

[ma96782]

To shift from 4x4 to 2WD:

Push the 4x4 button; the 4x4 lamp on the instrument cluster will go out indicating the vehicle is in 2WD. This can be done at any speed. To disengage the automatic locking hubs, operate the vehicle in 2WD in the opposite direction for approx. 10 feet (3 meters) in a straight line.

From the manual.

Aloha, Mark

 

[Tony H]

Does the grinding sound like it is under you or in front by the Hubs?

The Auto Hubs may be going bad and without the drive of the Axles, they might be grinding around.

That would explain why backing up and totally unhooking the Hubs makes the grinding stop.

 

[DeRocha]

Sounds like your autohubs... the center part of your front wheels... Normally when you engage 4x4 the front axles start rotating and cause the front hubs to lock onto the front wheels thus powering them. When you disengage 4x4 the front hubs remain locked, but not powered. When autohubs are going bad they can buzz, chatter, ect as they bounce back and forth from lock to unlock...You can remove the hubs and try cleaning them as it is all too common for mechanics to over grease them... An over aboundance of grease is not good and can hydrolock the hub mechanism towards the disengage position...

 

[snocross1985]

I knew it was autohubs before I even openned the thread. Swap to manual hubs and never look back...

 

[Tony H]

A good way to check is to take the Hubs off totally. put it in 4WD and see if bot axles are turning. If all stays quiet... gotta be the Hubs

 

[Rustang©]

you said you had a 92, although, you got the noise gone, make sure to check ALL of the U Joints, i just had a lot of work done to mine, and all of the U joints were bad in mine, ALL OF THEM!!!! That seriously hindered my Beach DRiving, lol!!

Just and idea of the frustation involved witht he U Joint, it too a guys and a 20 ton press to free up one of em in my front end!!!

 

[DeRocha]

...Just and idea of the frustation involved witht he U Joint, it too a guys and a 20 ton press to free up one of em in my front end!!!

Been there and done that... I broke a 6 ton press trying to press out a U-joint... In most cases the front stub axle U-joints are the 1st to go (because they are the ones undergoing the most articulation via steering input)