Okay guys, my sidekick is currently getting the engine rebuilt, but when it was running I noticed that when in 4wd the steering wheel would pull to the left at a certain rotation in the tire? It felt like I had mud packed in one rim and was throwing it out of balance. It would only happen when the hubs were locked and I had been in 4wd for about 5-10 minutes or so. The pull speeds up with the speed of the vehicle and vis versa. It does not happen with the hubs unlocked and in 2wd. So my question is what could be causing this? Do you think it is a problem in the hub or diff? Thanks for the help.

Not sure where the problem is, but work from the outside-in. The bushing in the spindle that the CV shaft spins in might be causing drag and the cv joints on the shaft might be bad. That would also cause it to pull. If the cv joints and that bushing seem fine, then it might be the bearing on that side of the diff housing. If that's bad it could pull to that side. Since it only does it in 4wd, it has to be one of those things, it is probably not anything to do with the brakes, tire pressure or wheel bearings otherwise it would pull all the time.

Put the transfer case in 2wd, unlock the hubs and grab ahold of the cv shaft and see if you can turn it by hand. Do both sides so you can feel the difference. You should be able to narrow it down.

Thanks, I will try those things. What about the hub itself. ie. (locking and unlocking as I drive?)

If you have manual locking hubs, they are either locked or unlocked. They wouldn't kick in and out while you drive. If it only pulls when the hubs are locked, then I would suspect the driveline like I stated above. If you are running the stock hubs, you can easily check to make sure they are locking by the same method, lock the hubs and make sure the transfer case is in 2wd, then try to turn each CV shaft by hand. If it turns, that hub isn't locking. If the transfer case is in 4wd, the shafts wont turn even with unlocked hubs because they will be locked to the rear shaft, make sure you are in 2wd.

Even still a hub problem wouldn't cause the pull like you described.

I would have to say it is the cv shaft that has a tight spot. It is trying to straighten out everytime it hits that spot.