Engaging 4WD Causes Tracking Right and Left

So when I engage 4hi, it feels like it's tracking to one side or the other. This doesn't seem to happen in 2wd

I'll explain:

• I put it in 4hi and start to drive straight and it'll track to the right.
• I take a left turn on to a street and straighten out then it pulls to the left.
• If I take a right turn onto a street, after straightening out it'll pull right.

Basically, anytime I turn the steering wheel past a certain point in one direction, it'll start to track to that side after I've straightened out.

Anyone know if that has anything to do with the 4wd or do it is something to do more with the steering components and is only more pronounced when 4wd is engaged?

Also when I engage 4wd, I hear much more noise coming from the front diff and/or axles...Is 4wd always that noisy or does that have to do with the fact that the 4wd wasn't used much, if ever, in it's lifetime?

 

It's common to notice a little bit of tracking left or right when in 4wd compared to 2wd. As when you are in 2wd the front wheels do not have any power going to them the only forces on the tires are from the friction forces of the ground, they track in the direction in which the steering points them. When in 4wd the tires themselves are pulling the vehicle forward. The drive forces from the vehicle will actually cause the inner and outter tie rod assemblies to flex just ever so slightly allowing the toe alignment to vary just minor amounts yet enough to cause a little tracking left or right.

The effect your noticing from turning in different directions and then that altering the direction in which the vehicle is pulling, is due to the nature of a differential. When you make a right hand turn the outside tire spins more revolutions than the inside tire. The differential in this situation transfers power to the wheel that is on the inside of the turn allowing the outside tire of the turn to free wheel thus when you get back on the gas pedal coming out of the turn the majority of the driving force going to the front axle becomes transferred to that inside wheel causing the vehicle to track ever so slightly to that side. The effects can be mirrored to the other side of the vehicle when taking a turn in the opposite direction.

To counter this people with awd vehicles such as the V8 4wd 4runners they will have there alignment spec a .5 degree of positive toe so that when the tires are pulling forward they actually pull them self into zero degrees of toe.

You shouldn't really get that much noise from the front differential when in 4wd compared to 2wd I mean you may get some added road noise but it shouldnt be anything significant maybe its time to change the gear oil? Now when in 4wd lo you will hear the gears whining a bit in the transfer case as they are low gear ranges with a higher rpm drive gear but thats normal

 

Thanks for all that info! I figured there'd be a little more noise from the front in 4hi considering the front diff is engaged, it just sounds like more than I would have expected. I was thinking the same thing about changing the oil in the diffs. It's probably due anyway. Guess I know what I'm doing next on the runner.

Your description about the tracking makes sense and sounds like that's probably my situation. It's not tracking so much that it's pulling me off the road quickly...just kinda slowly drifting. Probably standard operation and nothing to be concerned about. Thanks again!