so, i just got my 2005 1500 4x4 and i haven't completely read up on it yet. also, this is my first 4-wheel drive vehicle.

but anyway, i had it in 4wd today and during a U-turn, it felt like the front end was locking up. im assuming this might be because of a limited slip differential in the front? or not, i honestly have no clue. just looking for some input.

 

yea its because the strain on your componints you shouldn't use in in 4x4 unless it is really muddy or slick

 

I would not use 4x4 in a U Turn on dry pavement.
Come to think of it, I wouldn't use 4x4 in a U turn at all, lol

 

Your truck doesn't have a limited slip front differential. What you felt was likely 'binding up'. When you are in 4x4, your front and rear differentials are being driven at the same speed. Now when you turn, your front wheels take a slightly longer path than your rear. When there is no way for the wheels to have slip, it 'binds up'. Try to use your 4x4 only when you feel the conditions will allow the front and back diffs to slip, in reference to each other.

 

yeah, I had figured

I was using 4wd because we were having some real bad rain, but i probably wont be doing that again.

thanks guys, great help!

 

Yeah Rain + 4WD is just asking for a spin-out.....

What you experienced is completely normal, but isn't very "good" for the truck's drivetrain, so don't do it often if you can help it...

Even in snow when I'm in 4WD I avoid turning to full-lock.

 

Why exactly does having 4WD on increase the turning radius??

I test drove a truck a while back and checked out 4WD (on dry pavement) and it significantly increases turning radius when enabled....like it's physically not possible to turn the wheel anymore, until 4WD is turned off.

I've always been curious about the physics of that but have yet to find a good technical description as to why.

 

In 4wd all four wheels drive = when you turn, lock to lock, all four wheels are straining to drive = one side of the truck has a a larger diameter turn, than the opposing side.

When your out of 4wd, your front wheels turn quicker and sharper because thiers no strain on the front drive axle to match the stearing componants ability to turn.

 

That's about as easy of an explanation that anyone can give... and it's basically completely correct, minus the binding bit.

I won't further complicate it.

Now if you are talking about the reason I never use 4WD in the rain, it's based on the same principle, if you make a turn and it's slick enough that you lose traction the wheels that are already on the path of the longer radius will continue to drive the truck in such a manner, which will worsen the spin, which make it harder if not impossible to recover control. The exception here is vehicles that have AWD with a clutch-type center differential that allow for torque distribution front to back and side to side, as they will drive all wheels at whatever speed they need during a turn, so they do not exhibit the same characteristics as our trucks when in 4WD.

 

Its not so much side to side difference, as it is front to back. When you turn in 2wd, your outside front wheel is taking a longer path than the inside, but because it is an open differential, it can 'slip'. When you drive the axle it still doesn't matter, it's still open. In the rear, there is still allowance for slip, even with a limited slip, within the differential. Same idea as the front. Now when you're in 4x4, you have essentially locked one of the front wheels, and one of the rear wheels (with the other 'kinda' locked to it) together. That one front and one rear wheel are turning at different speeds when you turn, giving you the binding.