91 Explorer 4 Wheel Drive Grinding

Have A 91 Ford Explorer With 127000 Miles That Is Giving Me Fits With The 4 Wheel Drive.
Front Axles Started Making A Thumping/grinding Sound Mainly After Making A Left Turn With 4 Wheel Drive Disengaged. If I Backed Up And Then Went Straight Ahead, It Was Quiet.
I Replaced The Outer Hub Ball Bearing On The Left Side-problem Was Still There.
Bought A New Hub Assembly And Put It On The Left Side, Problem Still There. Took The Left Hub That I Had Replaced The Ball Bearing In Along With The Cam Assy. From The Left Side And Put Those On The Right Side. It Was Dry Road So Didn't Engage 4 Wheel Drive For A Couple Of Days And Drove 20 Miles And Front Axles Were Quiet. Then We Got Some Snow. I Engaged 4 Wheel Drive For About 50 Feet To Get Thru Some Snow- It Worked Fine- Disengaged It And Drove Another Mile- Then Made A Sharp Very Low Speed Left Turn And The Grinding/thumping Returned.
I'd Appreciate All The Help I Can Get As To What Is Causing This.

Jay

I have the same exact grinding and thump when the 4wd is engaged and then fails to disengage.... which then requires backing up to entice the hub to unlock...

Please let me know if you resolve your problem as winter has not yet given way to spring.

I am tearing the hubs down... If I figure it out I will let ya know

can you please let me know too via email thomasace15@yahoo.com cuz when i try to emgage it i makes a loud cluncking noise and when i press the button to disengage it some time dont and when it does ill be driving about 12 a block and it will try to go back in and i have to stop the truck and it goes away i have to do it about 5 times till it stops

Im not sure on the newer trucks, but I always thought that when you disengage from four wheel, that you had to back up in reverse to undo the front wheel locks and that if you don't the two front wheels spin in tandem rather than independant. This would explain the knuckle thumping in your sharp turns at slow speeds. I could be totally wrong on this but that has always been my assumption...and you know what happens most times you assume! (ass-u-me )

typical auto-hubs,

they sometimes try to kick in when making sharp turns in 2wd,

and they will start to click and make awful noises when they start go to shit,

best thing to do when replacing is install Lock-out hubs like i plan on doing

Your going to be mad...
Your problem sounds all too familiar. and I can see why you went with the hub bearings, but you are going to get mad when you hear this. The problem is the probably related to 1 of three things... 1st it may be the upper and lower ball joints, they have a needle fitting that you need to grease every 15,000 miles RELIGIOUSLY. 2nd. also you need to check those doggone electric hubs, almost everyone who owns that vintage Explorer has converted to manual hubs, they are cheaper and far more reliable. Last but not least is the infamous "After shimmy" at about 60mph. these Explorers have a real issue with the radius arm bushings. they wear easily, make your steering sloppy and rumble. You can also feel them rattling the floor pan on the drivers floor. they are a pain to replace and you will usually have to take them to a frame shop to get them done. DO NOT let the dealer talk you into their "fix"...there isn't one from them. If you can talk them into it, ask them to add 2 extra .100 washers to them it will stiffen your steering and make it more predictable.

had the VERY SAME PROBLEM took off the s**t auto locking hubs went with warn manual locking hubs i believe were about 150 for the pair and new wheel bearings 4x4 works better then that in my 2002 yukon and hasnt made a single sound since the change over hope this helps you

I have a 1991 Explorer XLT and a 1998 Explorer XLT.We have replaced the automatic hubs with manual hubs on the 1991. with the 1998, the automatics make noise and we will be replacing them. If you don't use the 4x4 all the time, you can take the inner gears out,but you wont be able to use the 4x4.