1999 GMC Yukon • 180,000 miles

I have an '99 Yukon SXT 1500 4WD. Especially at higher highway speeds, there is a "grab" when steering to the right. It was much more pronounced but I have since purchased new tires and installed new shocks along with a front end alignment. The alignment helped the most but the problem still exits. At this point I'm thinking valve issue or steering box. Any suggestions to help diagnose the problem would be greatly appreciated.

December 7, 2011.

Is the steering overly sensitive?

No, responsiveness is typical, escept when it catches and the steering wheel 'jumps' about 3 inches when slight pressure is placed on the steering wheel. FYI, the gear box and idler arm have been replaced.

Dec 7, 2011.
There is a sensor in the steering column. I'm sorry but I can't remember its name; however, it is designed to provide power assist based on vehicle speed. It can either make the steering really sensitive or hard. When they start going bad, they do it randomly when light steering is needed.

I checked for the steering speed sensor in the column under the dash. There is none attached. Is that optional or did all 99 Yukons have them?

Dec 9, 2011.
I thought that was standard.