Information by Manufacturing Defect
Owners report a vibration while their truck is just getting underway (0-10 MPH). I have seen it blamed on defective exhaust parts, driveshafts, tires, wheels, hubs, springs, shackles, u-joints, driveshaft pinion angle and the carrier bearing.
35 - 45 MPH Vibration
There is a harmonic vibration as the truck passes through the 35-45 MPH range. I have seen it blamed on defective exhaust parts, driveshafts, tires, wheels, hubs, springs, shackles, u-joints, driveshaft pinion angle and the carrier bearing.
65 - 70 MPH Vibration
A vibration or shimmy is felt, mostly in the steering wheel, at a 65-70 MPH cruising speed. I have seen it blamed on defective tires, wheels, hubs, steering rack & pinion, and lower control arms.
Water Leaks into Cab
Trucks manufactured with defective seals around the extended cab doors or defective seals between the seams between sheet metal parts by the rear seat belt mounts. Dealers are replacing the rubber seals and weather-stripping the gaps in the sheet metal seams.
The steel rims are not within factory run-out tolerances, these defective rims in turn can contribute to the vibration problems listed above.
Abnormal Tire Wear
Abnormal wear pattern on tires/reduced lifespan. Exhibited by cupping on back tires and feathering on front tires. General tires have been known to have large chunks of rubber missing from the tread.
Seat Belt Retractors
Seat belt retractors are defective tightening up and locking around the occupant when the truck encounters a bump.
Cold Start Knock/Tap
4.8 and 5.3 liter engine were built with main rod bearings that have enough clearance to allow ticks and knocks when the engine is cold. The 2001 engines were changed to use rod bearings that have a tighter fit, eliminating the noise and any wear the movement might cause.
Cooling / Overheating
Coolant leaks from system causing overheating, odors being emitted through the air conditioner, low coolant warning from dash warning center, lack of heating and inoperable engines. This is caused by a defective engine coolant recovery pressure cap.
Sticking Accelerator Pedal
The fuel injection throttle body may stick. The defective throttle body's blade is too tight in the throttle body bore. The replacement throttle body has more tolerance machined in. GM warns against attempting to clean or adjust a defective throttle body. It must be replaced. Some dealers were trying to repair it themselves before GM issued a TSB.
Transmission Coolers that were never Installed
For a period of time trucks that were ordered with the heavy duty towing package were delivered without the external transmission cooler installed by the factory. You can check your truck by looking through the grill for a small cooling radiator directly in the center of the grill. It is in front of the radiator.
Rear Window Wind Noise
Extended cabs built in 1999 and the first part of 2000 incorporated defective rear windows and frames. They whistle loudly while at highway speeds, it is more pronounced with the air-conditioning or heating on high and not in the recirculate mode. There is now a new rear window and frame assembly GM is using.
ABS Over Sensitivity
Upon hitting a bump while applying the brakes the ABS takes over resulting in loss of braking ability. The pedal goes almost to the floor.
Pops and Creaks while Turning at Slow Speeds
Loud pops and or creaks are emitted from the front suspension / steering while moving forward or backward at a slow speed with the wheels turned. Sound is caused by defective coil spring isolators in the front suspension.
Harsh Transmission Shifts
While the transmission is shifting from first to second gears a double bump or harsh feeling is emitted from the 4L60-E Automatic Transmission (RPO M30). This is caused by the shift points programmed into the computer. Dealers are flashing a new program over the defective one.
Transmission Starts from Second Gear
When accelerating from a stop the transmission starts out in second gear, sometimes then dropping back into first with a clunk.
Transmission does not Engage
When accelerating from a stop the transmission reacts as if in neutral, after a few seconds it drops into gear.
When accelerating at wide open throttle at high RPM, the transmission emits a high pitched whine.
Engine idles erratically, however it does this inconsistently. Dealers are flashing a new program that controls idle functions over the defective one.
Rattles in the Dash
The dash emits a rattle on the drivers side around the air conditioner vent. The design of the duct leading to the vent is defective, allowing it to rub on the dash supports. Dealers are gluing in a rubber pad in between the duct and the dash support.
Unanchored or Rattling Seats
Seat tracks / mount are broken easily.
Rear End / U-Joint
Upon acceleration, braking, or hitting a bump a loud thump or clunk is heard coming from the rear suspension. It is caused by a lack of grease in the sliding yolk on the driveshaft and a defective design in the u-joint. Dealers are re-lubing the splines on the yolk and inserting a rubber ball in the u-joint.
Four Wheel Drive Failure
Front wheels do not pull when the four wheel drive unit is engaged. This is caused by a defective transfer case, clutch plates, and the wrong front drive axle lubricant.
Loose / Sloppy Steering Column
Steering column feels loose and sloppy. There is a intermediate shaft in the steering column that is defective.
Trucks equipped with 4.3 liter V-6 engines had defective crankshafts that were mis-machined by the factory. Dealers are replacing the defective engine assemblies with new units.
Windshield Wind Noise
A loud wind noise is heard coming from the windshield area. It is caused by loose weatherstrip around the windshield. Dealers are gluing the weatherstrip down with silicon sealer.
Doors / Hinges
Power Steering Pops
Power Steering Whines