Collision Bob

Hi Y'all... Here's the problem. When the vehicle is in 4WD, making a slow speed tight turn into my driveway causes the steering wheel to rock back and forth violently. Also it doesn't want to come out of 4WD when I go to shift it back to 2WD. What do you think is the cause?
Also at idle it hunts for correct idle speed and sometimes stalls. Any ideas on this one??? Thanx

jnicewan

The 4wd concern is normal in 4H/4L part time, because when turning the front tires are going different speeds compared to the rear tires, this causes driveline binding. Its really not a good thing to do and thats why 4H and 4L are part time.

The idle problem could be a number of things, like vacuum leaks, need of tune-up items or maybe the IAC valve is dirty. There are plenty of threads about cleaning the IAC valve and throttle body if you wanted to search. If not remove the air intake tube from throttle body and spray some carb cleaner on the throttle plate, and into that little passage above the throttle plate, its also best to remove the IAC to make sure it gets cleaned real good.

dave1123

Actually, I think your front axle u-joints are the problem. You apparently have the 242 Selectrac transfer case because you have the 2WD option. If so, you have 2 choices for 4WD. Full time allows the front and rear axles to operate at different speeds, but Part time locks the 2 together to drive at the same speed. You shouldn't use part time on dry pavement or it will bind.

Turning tight corners with standard u-joints under power will give a "hopping" feel to the steering. This is normal and increases with worn or binding u-joints. Later models went to CV front axle joints to eliminate this problem.

A little science. With any single "carden" joint at high angles, the output shaft will accelerate or decelerate every 1/4 turn. This is what gives you the "hopping" feel. If it's NOT under power, it does the same thing but you don't feel it.

Collision Bob

Thanx for the information . It was spot on. It was the U-joint badly worn in the front axle r/f.

dave1123

Be careful driving out the old caps. I went too macho with mine and bent the yokes so I couldn't get the snap rings to seat. I had to take it apart and spread the yokes back to their original width, using a caliper to match the dimension of the joint snap ring grooves. It pissed me off, because I know better!

Try shifting the trans to neutral before trying to shift to 2WD. If it still binds, it may be the linkage needs lubricating.