Jumps and Lurches in 4x4...

[Redneck Youth]

when im driving forward in 4x4, my truck lurches and jumps, any ideas?...

 

[RatDog8o8]

Driving in a straight line, or turning? Are the tires on the front axle the same size (diameter-wise) as those on the rear axle? Gear ratios match up (if you did a swap of some sort)?

 

[Redneck Youth]

nope, everything is stock. 235x75r15's all around, stock front and rear axles and gears. and its only when turning

 

[85_Ranger4x4]

nope, everything is stock. 235x75r15's all around, stock front and rear axles and gears. and its only when turning

If it is really sharp or on dry pavement rest assured everything is fine. Now quit doing that before you break something.

 

[Redneck Youth]

ok, then if i shouldnt worry, can i at least get an explaination of why it does this?

 

[Endoverend47]

ujoints in the axle shafts are binding up because there is no give on cement.

 

[scotts90ranger]

yes, there is no center differential, the front and rear tires turn at different turning radiuses during corners, things are binding up and usually the tires traction gives first, but others something else goes...

 

[Redneck Youth]

alright, thanks guys

 

[Gary101386]

it wouldn't hurt to take a visual glance at your u joints and make sure there isn't any slop...

 

[RatDog8o8]

Some 4x4s do this "pavement hop", some don't. My CJ-7 doesn't (no hubs), but my F-150 & Bronco both did (D44s w/manual hubs in both). My Ranger doesn't do it, either.....and I leave the hubs locked for a few weeks at a time when they yap about snow on the news.

 

[GoodOld85BlueBalls]

These systems are considered part time systems for off road use and intermittant use under other traction limited conditions---not dry pavement.

When turning, the four wheels each make a different radius track, which means that each wheel is turning a different speed. The differential in each axle allows for this speed difference between wheels on the same axle. Despite the front and rear axle ratios being the same in a 4X4 they spin at different rates when you are turning. Yes, it is not much at all of a difference BUT on dry pavement it is an issue.

That is why everyone knows you need some type of medium like sand, dirt, mud, snow, ice, etc... that allows some slippage. If you use it on dry pavement then it causes axle bind. And it is normal to have it bind up when you are on a loose surface of dirt, rocks or snow. The tighter the radius of your turn the more bind you will get. I have found over the years, even off road, that I have had to take a truck out of 4wheel drive to make a tight radius turn.