tested out 4wd in the highboy today

[1971ford]

When i lock the hubs and put it in 4lo and turn , the steering wheel jerks left and right intensly. What's causing it, any ideas? I was turning around at the end of the court i live on. I had to stop midway and unlock the hubs.

[CO684X4]

Try it in the dirt. Driving and turning in 4lo on pavment does that. The front end binds on tight turns on pavement. Good way to blow ujoints if your not careful.

[papabug71]

Dont ever use 4 Low on hard surfaces. Unless your going in a straight line. Turning at full lock in 4 low on pavement will make parts come undone.

[fordman]

it is because of the agresive ness of the tires yo uhave on it. i have plain street tires on mine and it wont do that. but i do get stuck in the mud easier.

[fireguywtc]

Agreed, dont use 4wd on pavement, either high or low. The front wheels are turning at a slightly different rate then the rear when you are turning and will lurch forward when you are pavement.

[1971ford]

gotcha... won't happen again.

Fordman... the tires are street tires. It shouldn't matter what kind of tires though.

[Hawkrod]

gotcha... won't happen again.

Fordman... the tires are street tires. It shouldn't matter what kind of tires though.

Tires do matter, BIG TIME! It is important to note that the front and rear axles are usually not the exact same ratio and when turning the front tires do turn at different speeds. Because of all of this it is dangerous to drive a 4X4 when engaged on a surface that provides good traction. It is also important to note that the front should not be that bad unless it has a limited slip or locker or is otherwise "tight". A differential is designed to allow one wheel to turn at a different speed than the other (that is what differential means! LOL) but when traction is good and all is tight then broken parts are not very far away as these guys already noted! Hawkrod

[speed bump]

You are learning a valuable lesson about rotating tires and buying matched tires for 4wds.

[fomocoguy]

Good job on having the smarts to unlock the hubs when you sensed something funny going on. Take her out in the dirt and try again. You'll get much better results!

[1971ford]

So why is it that this happens and it wants to break parts? Is it like if i were to have the front gears welded and in 2wd?

[averagef250]

It's perfectly fine to drive on pavement locked in 4 wheel drive, but you must know your limitations. If you steer tight, you will be twisting your front and rear axleshafts, if the tires cannot slip on the surface they are on and you have lighter duty axles you will break something at some point, likely in the front axle.

If you have 1 ton stuff you don't really need to worry about it. As long as you don't turn full lock, put a front tire against an immovable object and throttle down on it it's pretty hard to break anything when the parts are in good shape. The tires will just unwind on their own when you hit a bump or a soft surface.

If your 44 front axle is in good shape it's not really that easy to break parts in it either. However, odds are you will probably find pushing the truck to it's 4x4 limits far more exciting than making sure the axle is in top shape.

[mlheppl]

So why is it that this happens and it wants to break parts? Is it like if i were to have the front gears welded and in 2wd?

Here's the why it happens: When turning, both tires are essentially making an arc or circle. The outside tire will make a wider arc than the inside tire will. Being as the hubs are locked, both tires are rotating at the same speed. The outside tire making a wider arc, yet rotating at the same speed as the inside tire, will inevitably fall behind the inside tire. While in low range and on flat pavement, there is less opportunity for the differential to allow the outside axle to slip and catch up. Therefore the outside tire will lunge forward to catch up with the inside tire.

Hope this helps.

Mike

[hazelnut]

This would be true if the front axel is positrac, but most front axels are open or single leg and that allows the front tires to turn at different speeds when your turning the wheel to make a turn, the same as most front wheel drive cars on the road. the reason that a steering wheel jerks back and forth is because the rear wheels are pushing the front wheels and when you make a turn because the rear wheels make a shorter circle or track to the inside of the front tires and are pushing the front tires foward at a different rate than their spinning foward or a easyer way to say it is your tire are trying to go in two different directions at the same time, thats the reason a steering wheel jumps more the further you try to turn the wheel. The gears in ryans truck should be 4.10s front and rear and so rolling straight with tires the same size would have all tires pulling the same going foward.

[1971ford]

Interesting. I'm awair of the outer tire making a bigger circle (have experienced it plenty with my previous locked rearend in the race truck), but I was wondering why the front axle acted locked when it is open gears. But It makes sense being that when you lock the hubs in you are locking the wheels together. I still don't fully understand how locking hubs work, i need to read up on it.

Hazelnut thanks for the explanation on why the wheel jerks, i didn't think of the rear tires making a smaller arc too, but it definately makes sense.

Dustin I am unaware of the current shape of my axles, but I plan on checking them out when i restore the whole chassis. I want them to be reliable as possible of course..