It's fine going striaght until I go to turn the Drive train make a big clunk, and it's not the tires

 

I've heard that a few times when I've had 4x4 on, not exactly sure what it is, but it hasn't caused any noticable problems yet. Mostly though I get a light grinding / rubbing noise from it (especially when turning).

 

If you are using 4WD on dry ground- that is the reason for the noise. The front tires must be able to slip (snow, ice, mud) or you will get the grinding sound b/c your drive line in the front is binding up. Your front wheels are turning at different speeds on turns- hence the grinding sound.

 

^what he said. try not to do it too much

 

i thought the reason why they bind up is becuase they cant turn at different speeds

 

They want to turn different speeds but because there is no center differential in the Transfer case they can only go as fast as the rear tires so they need to be able to slip which won't happen on high traction dry pavement.

 

yes so in turning a corner the outer tire should turn faster then the inner but cannot so both are moving the same speed which causes the axle to drag the outer tire while turning because its traveling the most distance

 

Actually, you are close. What you are describing would happen with a locker in the front axle. (side to side)

The 4wd binds because the front takes a longer arc through the turn than the rear does. That causes the driveline to bind because the longer arc causes the front wheels to turn more revolutions to cover the distance.The rear wheels don't have as far to travel, they turn slower.

Even in a straight line it will eventually bind up.The tires (front and rear) would need to be EXACTLY the same size for it not to .Even brand new tires aren't that exact in size. Factor in wear, and they aren't even close.

 

anywho it doesnt matter WHY it does it.

all that matters is that it shouldnt be done if you can help it

 

That is actually what I meant to say. The front wheels are trying to turn at differnet speeds -but they can't which causes the front drive line to bind. The inside wheel is turns faster than the outside wheel on turns. This is what causes the axels to bind.