I've finally gotten a chance to really get a feel for my 4 wheel drive after being afraid of using it for prolonged periods. I think I've pretty much ruled out the transfer case itself.

Anyway when I'm in 4 wheel drive, I will be driving and all of a sudden I'll hear clunks under my feet and sounds almost like something is binding, I thought the transfer case was going out for the longest time being the longer I was in 4x4 the more it would hum. I've noticed it does it after I make somewhat tight turns, and for a while I could not go over 40 mph with it. It never really binds up when I'm making a turn but always when I'm going straight just cruising.

It doesn't do it all the time, last month I drove about 100 miles in 4x4 in snowy weather with no issues until I pulled out of a parking space at Wal Mart and it started acting up again, I turned the wheel the opposite way I had just turned tight and it seemed to get things back to normal and I even cruised 60mph on the highway buttery smooth.

Could one of my u-joints on the front axel be binding I'm wondering?

Does it weather I'm in 4w low or high.

 

Don't use four wheel drive where you have traction, the driveline binds up, and gives you the exact behavior you describe. If there is significant snow on the surface you are driving on, you should be ok.... otherwise, don't do it.

 

Kinda baffles me this binding noise. It happens AFTER making left turns and actually NEVER does it during a turn. My sisters 2000 Ram never does this noise while driving on the same surfaces as I do. I was going through about 7 inches of snow crawling up an alley that was on a hill in the city going to my friends house and it binded up even going 5-10 mph. Its weird because it doesn't always do it, I can go forever and it will be normal and it will bind up to the point I get worried I'll toast my transfer case.

My dads 74 Ford with a Dana front axel has had the hubs locked in 4x4 all the time and has never seen 2wd in 30+ years! as its his plow truck. This binding has never happened to him. Of course you will always get a binding during a tight turn with 4x4 but mine does it in a straight line regardless of the surface. Any ideas what might be binding? I'm wondering if possibly the 4x4 vacuum locker isn't completely engaging all the way? I have to generally back up a few feet & drive forward before the 4x4 light goes off, which made me think it may not always be engaging fully, though I do have very good 4x4 performance minus this issue.

 

I would look at transfer case.... and Tcase saver. Mut +1 on waht HeyYou said. I seldom use 4wd in my Yota even in snow, unless I get into a spot where it starts to spin in 2wd. And never a tight turn, dry pavement, etc. If your sister's is responfing differently, something is jacked.

 

Also check what gear ratios you have front and rear..... (may have to pull covers to really verify it... but, that gives you the excuse to change fluids too....)

 

clunks under you feet sounds like front drive shaft u-joints. i has the double-carden thingy. it's rebuildable by you or a drive line or machine shop.
http://www.pavementsucks.com/tech-article-16.html

it could also be the chain in the t-case.

another source of clunks under driver or passenger feet is loose front shock lower bolts. torque to 110 pounds.

front axle u-joints turn in both 2wd and 4wd, so if your problem is only in 4wd, its not those.
driving in mud or snow is fine and should allow plenty of tire slippage to avoid binding. 4wd on dry pavement is a no-no.

 

I should clear up that it only happens in 4x4h and 4x4 low and it sounds like its in the differential and or axels. Its tough to pin point. I was showing off to my girl friend going up some more steep alleys tonight (we got a ton of snow to play in today!) and I went through a foot of snow up an steep unplowed alley and rammed through a 5 foot tall snow bank that someone plowed into the alley to block it off, and in the middle of that my differential was making that noise going straight up the hill and through the snow pile. Traction was amazing so I know it was engaged, felt like I was a rocket going into space on that steep of an incline when I punched it.

If I can get ahold of a decent video camera I might be able to get video of whats going on when it happens. And just to add to the fun I'll even go up that same alley and bust out of the other end of the snow bank like a boss lol.

 

^That'd be great^

I was playing in some frozen mud two days ago (breaking through the ice like a ship in frozen over water type of thing) Everything was fine. Last night I was going through some snow about 6"-7" deep and I was getting a clunk as you described under my feet and also in the front somewhere while turning in 4x4. Today after work I'm gonna do some investigating, I'll keep this thread posted. My double cardian U-joint is also squealing really bad now even though the U-joints are all new. I'll try greasing them.

BTW: Don't cheap out on u joints if you go wheeling. I used impact grade u-joints all around EXCEPT the front of the front drive shaft because I was impatient and didn't want to order and wait for it. Six months later it's shot. Not seized, but the little rollers in the cups all flattened out and made it sloppy.

 

Looks like I have worn trailing arm bushings on the front axle and where they meet the frame (I never changed them when I added the front axle) maybe take a look at those on your truck too. It makes sense that it only happens in 4wd while turning, because that's when the axle is fighting the rest of the truck the most. It also explains why it feels like it's under my feet.

I'm noticing an increased loud vibration when in 4wd now though. When coasting and decelerating it's smooth and quiet. ONLY when I apply some throttle (a little or a lot, doesn't matter) that it vibrates and is really loud. It has almost a metallic rubbing sound to it, with the sound of the vibration mixed in with it. (Possibly that "binding" noise Josh talked about?) Any thoughts? Could that sloppy U-joint I mentioned earlier cause this? Should I start a new thread for this? Can I cram any more questions into one post? (lol)

 

Change the u-joint. If it's sloppy, its dangerous.