I am having a strange problem with my 91 4Runner. It drives fine in 2wd but when i put it in to 4wd the truck wants to pull to the right really bad. The truck also feels like its shaking. If i put it in to 4wd while stopped (drive or neutral) the front right wheel is locked and wont turn. It seems like the brake is locked? I changed the diff fluid and just fixed a noisy spindle but didn't fix the 4wd problem.

 

might be a blown cv axle? dunno why it would be fine n 2wd tho, you have add or manual hubs? if you got manual unlock the hub n try to turn the cv it should turn easily

 

I have the ADD hubs. Seems like if it was cv axle i would still feel it in 2wd.

 

Except the axles don't turn when it is in 2WD, unless the hubs are locked. Right?

 

correct if you have the ADD system i dont see how the right side would be locked and not the other one you may have a seized cailper and that may be why you feel it pull to the right the only reason why i can think of it pulling more when in 4wd would because you would have power to the front tires and not only trying to stop 2 rear power tires but 4 power tires. if i was you i would pull the wheel off and check the cailper to see if it it locked one way to tell is to drive around in 4wd and see if you see smoke and or the wheel is hotter than the others. how the system works is all vaccum operated and there is a fork in the front diff that locks the diff into 4wd so it is pretty hard to have one tire locked up unless like said you have manual hubs and one is stuck in the locked postion

 

I don't have manual hubs, so i think that the axles are spinning all the time even without 4wd engaged. I remember reading something about 4wd ABS. Does this only engage when the 4wd is engaged?

 

Replaced brake pads and the caliper did not seem ceased at all. Still same issues.