[WrecklessAbandon]

Well this question does have to do with pavement and 4x4...If I switch my truck into 4x4 on dry pavement and go to make a sharp turn at slow speeds why does my truck seem to jump? It's almost like the brakes are catching or something....Is this normal? I know I don't need 4x4 on dry pavement but it's something I noticed. Let me know.

 

[Rawkon]

I dont have an anwser to the problem but i also have a similar problem, every once in a while (1 time a week or so) my driver side front brake feels like it goes totally loose and when i hit the brakes it will grab really hard and locks that tire. then after pumping the brakes a few times it re-adjusts itself to normal.

 

[79W-150]

I believe its because your front axle is locked in 4 wheel. The rear axle is probably a limited slip (one wheel can turn faster than the other, like when going around turns). But the front axle typically is a locked axle (both wheels turn at the same rate regardless) which will cause one wheel to bind when on hard surface like pavement.

My truck ('79 W-150) is all time four wheel drive, I have no way of putting it in 2 wheel because the transfer case is always locked together. So I have that same problem everytime I drive the truck. On highways and stuff its no big deal, but swinging a tight turn, u turn, and pulling into my driveway are a little hairy.

If you have two wheel drive use it on pavement whenever you can. Fourwheel is not designed for pavement use all the time.

-Chris

 

[canyonero02]

94-01 rams dont have locked front axles, theyre all open. but it doesnt matter it'll still do it. because the front and rear wheels have the same power going to them unlike an all wheel drive car where it distributes the power where it needs it so it doesnt kill your drivtrain and wear your tires. i wouldnt do that anymore, its rough on your 4wd system.

 

[jprtroy]

Yo, My rock ready CJ-5 does the same thing! It'll buck when I try to turn too sharply on or off road. It is locked (power lok up front) It is good to engage the front axle once & while. Like when on a straight-away. But I would avoid sharp turns on pavement (unless wet) while in 4 wheel drive. Avoid the bucking!

later...

 

[unclemark369]

Man I dont know but if you own a real 4x4 like a DODGE you dont use 4x4 on the pavement especially on dry pavement. Now if you own a 4x4 ford ranger like I used to the owners manual says you can use it on pavement slightly wet or slipery but not dry. It makes it harder on the universal joints in the axle. You know where the wheels turn the hopping come from the rear wheel trying to push the truck foward and the front wheel trying to turn the vehicle sort of working against each other. I believe....I think.... thats what I was told by a local 4x4 shop

 

[ruffram]

My truck does this no matter what I'm on, mud snow ice pavement whatever. It was worse with little tires, 33's don't do it as bad probably b/c the are heavier. It makes sense when I think about it anyway. I think and have been told that what causes that hopping feeling is that when you turn sharp it puts that cv joint at a very sharp angle. Cut the wheel and look some time, that joint has to do a lot of twisting to roll the wheel over once. WHen power is applied to the axle shaft, it has to overcome the binding power of the shafts being so far out of line with each other. When it does overcome it, it flips over quick and usually my steering wheel will yank the other direction real quick b/c there is so much force, it has to straighten the wheel before the joint can roll over. I had to replace both my front joints and off the truck you can really feel how much force it takes to roll it over at that angle. By the way doing that a lot is what causes you to have to replace your ujoints so don't do it unless you have to. That makes no sense even when I read it. If anyone understands that I'm glad but you probably think I'm an idiot......you're probably right!

 

[woody]

The reason is because the transfer case locks the front and rear axles together, meaning each one's ring-gears spin at the same speed.

When you turn a corner, the front wheels make a wider arc than the back wheels (go do a few turns in a bit of snow/soft dirt (slowly), and you'll see what I mean.

Since the whole truck is going the same speed around the turn, but the front axle is farther away than the rear, it needs to spin faster. However, the t-case won't allow this.

It doesn't matter if you have open or locked axles, as the t-case itself is "spooled". Now, lockers do make it worse.

Essentially, if you do a tight turn on dry pavement in 4x4 (hi or lo), something must give. Usually it's the traction of your tires, and the fronts will chirp and jerk. The wheels will always want to straighten out, because to turn does some pretty bad things to the whole system.

If you do it often enough, the t-case chain will stretch, u-joints will fail, and you'll eat through tires REALLY FAST.

Now, in the soft-stuff (mud, sand, loose dirt, snow, ice), the fact that the drilve-line wants to go the same speed, but that the wheels need to go different speeds isn't much of a problem, as there's so little traction that something just spins or drags a bit. No harm done. Ever watch a fully-locked truck climb a hill of dirt? Everything just spinning the same speed, and the truck moving slower than the wheels are spinning (but not by much). This is what's happening when you're off-road, and why it's ok. You just don't have enough traction to break things.

BTW, don't spin tires really fast in 4hi/lo, if there's a good chance of suddenly gaining FULL traction. You'll break your axle, because the whole thing is spinning together. Even if you have open differentials (I know from experience).

 

[ruffram]

Thanks, that makes a lot more sense than that crap that I was rambling on about. (Anybody know how to delete a dumb post that made in a moment of ignorance?) By the way Woody, how bad do those 35's rub with a 3 inch?

 

[79W-150]

Yeah, go back and click on the edit button for that post. Then click on the Delete check box before you click submit.

Or just ask me too <IMG SRC="/board/images/smilies/icon_wink.gif">

-Chris

 

[WMIF]

Just as a side note...... Its not good to run in 4 even if youre going straight. Most of the time your front and rear axles are fitted with different ratios, and on the cement that will either wear your tires down or kill your drive train.

 

[DudleyDodge]

I've never heard of a stock truck with front and rear axle having different ratios.

 

[JasonB]

Actually the front and rear axles can be up to 1% or so different. For instances, the front axle is 3.55 and the rear is 3.54

 

[WMIF]

My truck has 4.0 in the front and 4.1 in the back.

 

[woody]

As to the rub with 35s and a 3" lift? None. <IMG SRC="/board/images/smilies/icon_smile.gif">

I'm running a Rancho performance lift (dual shocks up front), with rear add-a-leaf, and 315/75R16 BigO XTs on 16x8 wheels.

JasonB probably knows the backspacing of the wheels, I've forgotten it.

But fully stuffed, nothing. turning hard, nothing. But I'm also running the stock control-arms, and the Rancho arms may be wider, and so may rub a bit there.

The 2000-01 trucks have some larger bolts in the front-end that didn't allow me to put on the Rancho arms at the time. I could now, but it works pretty well.

 

[woody]

moved the trackbar info to it's own thread:

http://www.pavementsucks.com/forums/viewtopic.php?topic=463&forum=11&0

I hope that link works...

 

[ruffram]

Are those Rancho control arms longer than stock? I have heard that 3inch lifts use the same length control arms. In any event, I need a way to set the axle father forward. I was about 4 inches of lift on the stock control arms, and the axle is pulled backwards and slightly of camber. When I turn the wheel while sitting still if lifts each side of the truck a noticeable amount. To me this meaans that my axle is tilted backward slightly because the lower control arm is not long enough. Any suggestions?

 

[woody]

The Rancho arms are stock length. Skyjacker's 5" kit arms are the same length for the uppers, but longer for the bottoms, to correct the camber when turning, and to help push it forward.

You're best bet is find out the length of the skyjacker arms, and see if they'll work with 3" of lift, or have your own made.

I know of a few people that have gone teh custom route. Easiest is probably to make skyjacker-like arms, but it could get expensive.

Get thick-walled steel tubing, cut to length, and weld on some big a** nuts to the end, or a threaded collar of some kind, and thread a heim-joint into the end of it. Voila! You now have a Skyjacker "flex"-series control arm. But those joints are $$$.

You also may be able to buy Rancho arms (rectangular cross-section tube-steel), and extend the length by cutting them in half, and welding in a spacer. But I'd make sure that you find a REALLY good welder/machinist, and tip him well. If a control-arm fails off-road, you're going to break a lot of other stuff at the same time...

 

[ruffram]

I may very well end up having a set made, it would be nice to have that adjustability in there. I have asked this before but I'm doing it again. Are the bolts that connect the LCA to the axle offset like the lobes on a camshaft? If they are it would seem like I could twist those to correct the camber problem. If they aren't offset then I guess I am back to square one.

 

[woody]

Yes, the lower control arm bolts have a cam built into the head of hte bolt, or the nut, one of the other. That can be used to adjust the caster of the front axle (I think that's the term). When I installed my 3" Rancho lift, they said to keep the angle the same, so you may want to mark the current angle, then start playing with it to make it come out the way you want.

Let us know how it goes (use a new topic, though).