I have a 91 b2600 4x4 with 100,000 miles. It has 31x10.5's on it (has for a long time) and is developing a serious steering shake from 45-60 MPH. The steering wheel moves back and forth, but the truck stays on course. It is really annoying, and is probably not good for the tires or gas milage. I know that having larger than stock tires on a truck will increase wear, but I was wondering what I need to look at to replace. The truck was aligned, tires balanced, and the idler arm replaced all about 9 months ago. I had been thinking the next thing to look at is the pitman arm, but I don't want to mess with it if I don't have to.

 

Before you go to checking the pitman arm, check out your fron wheel bearings sometimes that is a sign of a bad wheel bearing.

 

Check ball joints, tie rod ends for looseness, as well as the wheel bearings.

 

I should have mentioned in the original post that the front axle shafts and front wheel bearings were replaced about two years ago, it would seem too soon for them to be going bad unless the parts I used were defective. I was wondering how to check to see if the ball joints and tie rod ends are loose. Last time I had it on the lift I tried to figure out where the play in the steering was coming from, but everythingseemed to have a similar amount of play. Isuppose that this could be a sign thatthe whole frontend needs to be replaced, but I really hope not. Thanks again.

 

Once it's in the air, pry stuff with a huge screwdriver or bar, check for looseness or movement.

 

Since the bearings were replaced two years ago you might want to go ahead and check to see if they need to be repacked depending on how many miles you have on it since the r&r of them.

 

I had a similar problem with my 90 b2600 4x4, when the truck got up to about 30-35 km/h there was a violent shaking from the front end it never affected the steering, i thought the whole truck would fall apart. What it turned out to be was where the axel shaft passes through the steering knuckle there is a small needle bearing here this bearing was destroyed. i replaced the bearing and it solved the problem. If your truck has free-wheeling hubs unlock them if the shake goes away this is definitly your problem. If not the next place to suspect is the pitman arm, to determine if the pitman arm is bad have an assistant sit in the truck and move the steering wheel, if any movemnet is observed at the pitman arm it should be replaced.

 

Thanks to everyone who replied, I will try these things and hopefull let you all know what I figure out.

 

Thanks again for all the advice. I took it to the shop last week and it did end up just needing to have the tires balanced. It drives like a dream now and it was a cheap fix.