GM Steering Column Repair - Clunk No MorePosted in How To: Transmission Drivetrain on June 1, 2008 0) (
If you own a '99-'07 fullsize GM truck, SUV or Hummer, you may have encountered the common clunking, groaning, or creaking that emanates from somewhere forward of your steering wheel. In some cases, the annoyances reveal themselves as early as about 10,000 miles.
The symptoms have been described as a clunking noise under the hood that can be felt in the steering wheel, or a rattling noise from the steering column that is often present during low-speed steering actions. It may also be heard as a groaning noise when making sharp turns at low speeds.
Often, the issue is a due to a bad intermediate steering shaft. The shaft moves slightly when the truck body flexes on the frame. The column is mounted to the body and the steering box is mounted to the frame. Some models were built with rubber isolators, and some were not. The stock GM steering shaft contains a splined slip joint that comes from the factory with grease in the slip portion. Over time, this grease slowly works its way to one end of the joint, and the slight play in the shaft pieces causes the noisy condition.
In the past, when customers came to dealerships complaining of the steering noise, a mechanic would often remove the shaft and rapidly cycle the slip joint by hand to redistribute the grease in the splines. This would usually quiet the shaft but was often only a temporary fix. Some months later, the noise would often return.
GM released a lube kit (PN 26098419) to help address the issue, and dealers or DIY'ers could repack the splines to fill the space and keep the shaft from clunking as vibration was transmitted up the shaft. The lube used in the kit was purportedly a heavy damping grease. This lube kit has since been discontinued as it was not an effective solution to the problem.
In early 2007, GM released a new steering shaft (PN 19153614) to try to address the problem. However, results are mixed as to whether this replacement worked and many drivers reported return of the clunking after only a short time. Service bulletins have instructed dealerships to relube the shafts with NYE grease, and other bulletins have advised disconnecting and stroking the shaft five to six times to redistribute the grease in the splines rather than relubing the shaft. Still, it seems these exercises are needed about once a year or so to combat the clunking shaft issue.
It appears that the shaft design, combined with the grease slowly migrating to the bottom of the shaft, causes it to start making noise. It may be possible that heat in the engine compartment also contributes to the grease flowing downward on the steering shaft. DIY'ers have tried experimenting with various homebrew methods of silencing the clunking shaft. Some have tried various greases, including brake-caliper grease, with some success. Others have used heatproof antiseize paste compound or even applied RTV silicone to the slip portion of the shaft. Still other owners have added a grease fitting to the shaft to allow for periodic lubricating, but any modification such as this should be considered with great care since this is a steering component.
We found an aftermarket part that addresses the deficiencies of the stock Chevy shaft. Borgeson Universal sells a replacement intermediate shaft that is built to be a more precise and solid unit over the stock piece.
When we unpacked the Borgeson shaft, we were impressed with its construction and heft. While the stock shaft uses a splined engagement, the aftermarket piece uses a slotted double-D sliding joint. The shaft utilizes one of Borgeson's machined needle-bearing U-joints. We've used these joints in the past and found them to be durable and long-lasting. This unit should provide even more benefit if you've added larger tires to your truck.
Installation of the Borgeson shaft took less than half an hour on our Silverado Z/71. Once installed, we could immediately tell the difference at the steering wheel. The steering response was overall tighter and felt more solid. Gone was the annoying bumping and groaning we used to feel through the wheel and steering column. We're hoping this shaft brings an end to the steering saga and the periodic maintenance that was needed to tame the clunk.