I have an f350 sd 2008 with only 11000 miles on it I had it 4 hi the other day and when I make a sharp left turn the wheel pulls and it makes clunk sound from the front tire area any one tell me what this is and if I need to be worried truck is stock tires and wheels 18 inch

 

I have the same "problem". Its just 4 wheel drive because both front tires are locked and have power going to them, when you turn it feels like one wants to skip because they are trying to go the same speed. Its normal

 

Thats actually incorrect. Each axle (front and rear) has a differential which allows for slippage of each wheel. Meaning on each axle (unless it has a locker) one tire is able to travel slower/faster than the other without binding the drivetrain. The binding you feel when in 4 on dry pavement is actually the binding between the front and rear. If both front tires were "locked" then you would get that binding any time the hubs were locked, regardless of if it's in 4 or not.
Also I think the clunk sound is probably more of a heavy clicking than a clunk. Am I right handyman? What is going on is when the wheel is turned at it's max and the hubs are locked the u-joints are starting to bind causing a clicking sound. It's just another flaw in Fords design. This will happen anytime the hubs are locked, 4 engaged or not.

 

Well my uncle and father told me this who have had 4 wheel drive cars since they could drive and they are both 50 years old, so I believe them. And the same thing happens in my uncles F550 and my fathers works F350

 

The clunk is the binding of the front driveshaft and the rear driveshaft when in 4wd. turning in 4wd causes the front and rear driveshafts to be turning at different speeds.

You may only notice the clunk and the slip from the front wheels because everything is bolted together and has no slip. The tires are the only thing in the 4WD system that can slip (dry pavement or not). If you don't have any slip, you can't turn, open diffs or not. (hense the reason why not to drive on dry pavement in 4WD. The binding is worse,as it takes much more binding to force the tires to slip a little and relieve the binding. In tight turns in 4WD, the speed difference between front and rear driveshafts is huge. The front is actually turning much slower than the rear. This causes you to feel the binding and the hopping ( as i call it) as you push the front tires around a corner in a turn on dry pavement.



The main difference between an AWD and a 4WD is a clutch or torque converter in the transfer case to allow slippage between the front and rear driveshafts.

 

a little story my ma called me up and told me that somthing was wrong with her 99 tahoe 4x4 when she turned left she would hear a clunking sound. so being a good son i went over her house to invistisgate. I jumped in her suv and drove it around the block sure enough the 4x4 light was still on after a snowfall 3 days ago. i pushed the 4x2 button and fixed the problem. and explaned to my ma how 4wd works and why she needs to turn it off when on dry pavement.

 

Hate to revive an old thread, but I think this is exactly what has been causing me heart break this winter. Just moved to a very snowy area but commute to a lower altitude and thought I would just keep my hubs manually locked for the winter. (I have my doubts that the auto lock are working 100% of the time).

But on dry pavement, in 2wd mode the heavy clunking/clicking of turning just sounds awful.

I've heard of folks locking in hubs all winter, perhaps this is an argument to not keep them manually locked in....

 

I keep mine locked all winter, without any issues.

 

Curiously, do you drive mostly on snow packed (or icy) roads?

Most days I alternate between snowpack/ice/dry pavement and have found what feels like binding in the steering column (and the click/clunk) on dry pavement such as parking lots.

 

I keep mine locked all the time too with no problems. Only once the t case is engaged will it get hard to turn and make noise.

 

Well that is concerning to me. In what situations would the transfer case be engaged if the **** is set to 2WD and there is no 4x4 light? I'm in a 2005 F250 FX4. The 4x4 light illuminates normally when I flip the **** to four wheel.

 

Depends on the winter. I am in Northern Wisconsin. Ice, snow, dry pavement, wet pavement, you just never know what you'll find.

 

I'm not sure I understand your concern. Hubs and t case are independent systems. The hubs can be locked without the t case being engaged. In a auto system the hubs are vacuum actuated but not a foolproof design. I have manual hubs and t case. I hate auto hubs and electronic t case.

 

You should not be feeling the clunking when 4wd is off even tho your hubs are still manually locked. Just for the heck of it, next time it happens, stop and go in reverse for about ten feet if you can and see if that solves the priblem. If that doesn't fix it, try putting it in 4lo and then back to 2wd to see what that does.

 

you don't have a locker in the front diff do you? This could cause binding when the hubs are locked (2wd or 4wd) also.