We have 2 99 3500 OBS crewcabs and the steering has gotten really loose on them. They are work trucks and both have about 70k miles. While driving, I can turn the wheels back and forth about 1/8th of a turn without turning the wheels at all. What is likely to have worn out? Pittman arms, steering gear? These are our tow vehicles for a couple of heavy excavators and towing with the steering like that is scary on little two lane roads. Thanks.