Hi

I have problem (or maybe it is not a problem but I do not know) turning car with 4Hi or 4Lo switched on. Turning4WD car seems to be a little bit stunted - as somebody pressed a little brake pedal. And I can feel a kind of resistance every wheel rotation (or maybe very half of full rotation). What could be a problem?

I can say I have front tires new and rear rather poor - could it cause the problem?

Regards, Marcin

 

Are you turning it on dry pavement?

If so, that's the reason it feels like that. It's normal, since the front tires are trying to pull against the pavement along with the rear tires. It's not all that good for your truck to run it in 4x4 on dry pavement.

 

It was not too dry pavement. It was raining and I decided to check 4WD mode becouse next two weeks in Poland heavy snow is expected.

Marcin

 

Even the rain doesn't really make for enough give, that's pretty normal for operating in 4x4 on tight surfaces.

 

It's called "Tire Scrub" or "Crow Hopping". 4x4's don't have a front differential so bothfront wheels have to turn at the same speed. When turning, the inside wheels are turning in a tighter circle then the outside wheels. A differential solves the problem by rotating the inside and outside wheels at different speeds.

When doing tight turning manauvers like parking or U-turns, disengage your 4x4 system. That's what I used to do with my 4x4 Sport Trac.

 

Are you sure? I know that there is no central differential but in manual theysay that front differentail capacity is 1,2 litre of fluidso I guess there is front differential

Marcin

 

There is definitely a front differential.

 

My bad. Yes there is a front differential, but I don't think it works like a rear with clutch packs, etc. I think it just locks the axles together. I had a really good 4x4/AWD Power Point from a Ford engineer, but I can't find it now.

<---- not a 4x4 expert.

 

Actually, the hop is caused by the fact that there is no center differential. Even with 2 open diffs in the front and back, you are still requiring 2 wheels to turn at the exact same rate. In a turn, no 2 wheels will travel the same path (ok so it is possible) and as such, they all are turning at a different rate. With a 4wd vehicle, this will result in one of those 2 wheels (the one with less traction) to slip in an attempt to maintain the same number of rotations as the other.

Here's an illustration:Different Wheel Speeds in Turns - 4x4abc.com

So yeah, it is completely normal.

 

No center differential, that's what I was thinking of. Doh.

Thanks for the explination.