Five problems related to hydraulic power assist steering system have been reported for the 1999 GMC Suburban. The most recently reported issues are listed below.
While driving at low speed and then on the freeway at 70 mph my Suburban lost powering steering control intermittently-on-off, on-off, on-off. At 70 mph the vehicle repeatedly jerked to the right, and I had to jerk the wheel back to the left and swerve back into the lane. Had inspection made, and found metal shavings in power steering fluid, indicating a component failure in the power steering system. I see a technical service bulletin was issued two years ago on August 1, 2003, but no further action to date to correct this safety defect.
While driving at 35 mph on curvy road, power assist failed, rendering steering excepetionally difficult to control.
While engaged in a turning maneuver, the power steering suddenly applies maximum assistance, startling the driver and causing the steering wheel to move suddenly. This movement in turn cuases the front wheels to turn suddenly while in a turing maneuver. If the driver is not extremely attentive, this problem can easliy cause a loss of control of the vehicle. As I understand from local repair shops and a local Chevrolet dealer, this is a very common problem with Chevrolet and GMC trucks and Suburbans.
Steering would jerk left/right intermittently under load (while negotiating bend in road). Problem progressed to power assist failure. Local repair shop directed us back to specific person at dealerhip telling us that they have sent several Suburban owners there with same complaint. Dealer replaced something in gear box. Problem was not resolved and has worsened. Truck back in shop this week. Dealer is investigating.
Power steering failed on two occasions.