Hey

This is a bit of a long story so bare with me. About a year ago I got a flat front left tire. I switched it out with the spare but all the other three tires are smaller than the spare (which is the stock size). Later that night I backed into a ditch. I put it in 4wd to get out. At the time I didn't know about putting it in reverse to get out of 4wd so I drove home with it engaged. It was skidding and making all kinds of noise. (I thought I ruined my truck). After I realized that I was stuck in 4wd with the two separate tire sizes in the front.

Now when I'm in 4wd my truck pulls hard to the left and makes a bit of noise. I'm thinking that the ADD system isn't locking both only the right wheel. (I don't know if I said that right, sorry). My dad and I are dropping the front differential this weekend to fix an oil leak can we tackle this problem too while we're at it?

 

I would guess something more like drag on that wheel(bearings, more friction in the cv joints, something of the like) or bad alignment. It doesn't take very far off on the alignment to make it behave very funny in 4wd, especially if you're driving on mixed high traction and low traction, like patchy snow.

The ADD system would give you no power to either front wheel if it wasn't engaging, unless you have a locker in the front diff. Then I'm not really sure which wheel it would engage, never really had to mess with my ADD.

 

Before you drop anything, jack up the front end (both wheels up) and examine it carefully. With no vacuum, the ADD should be disengaged, so you can turn each wheel easily, without it turning the other wheel or the front driveshaft. If you have a hand vacuum pump you can check how it works with vacuum. Personally, I wouldn't start the truck and engage 4wd with the front supported only by jack stands, but if you're extremely brave ....

As JonnyBoy suggests, it sounds much more like an alignment issue or some other front end damage. It just scrubs the tires in 2wd, but when you lock them up in 4wd they go where they want to go.

 

Totally agree its prob an issue with alignment or something worn out on the drivers side a little play will be alot more noticeable in 4WD than 2wd good luck with it

 

You could do scopes test with all the wheels off the ground. Kick it into 4 wheel drive with all the wheels off the ground and see if you get the same problem. At least then you could look at it while its driving and it won't come off the jack stands and kill someone