A complaint often heard among Silverado owners is about an annoying clunking sound emitting from the drive shaft during stops and starts. The noise comes from the slip yoke between the drive shaft and transmission. The slip yoke is a two-piece shaft with an outside sleeve, and an inside shaft. Both pieces are splined so that the inner shaft slides freely in and out of the sleeve while the entire assembly rotates to drive the rear wheels. As the splines wear, slack between the shaft and sleeve create a bumping, or clunk, sound when the shaft first starts to turn, begins to stop, or when slowing down from normal speed. Greasing the slip yoke will cushion the area between the shaft splines, and eliminate the noise.
Position the Silverado on a hard surface such as in the garage or on the driveway. The truck position should allow easy access to the rear drive shaft.
Set the parking brake on the Silverado and block the front wheels with bricks or wheel chocks.
Remove the forward U-joint connection from the drive shaft, which is directly behind the transmission. Back off the four nuts retaining two U-bolts that hold the U-joint in place. Using a 3/8-inch combination wrench, turn each of the four bolts counterclockwise to remove the U-bolts.
Set the front of the drive shaft on the ground and move it to the side.
Grasp the slip yoke sticking out from the transmission with both hands and pull it off the splined shaft. After separating the yoke, the spines are visible both on the shaft and within the sleeve.
Spray a light oil on the slip yoke shaft and wipe it down with a shop rag to clean it rust, dirt and debris. Cleaning the shaft allows the grease to adhere to the shaft better.
Apply a liberal amount of grease to the splined shaft by hand. Coat the entire length of splines and fill the valleys between the splines.
Slide the yoke back onto the shaft, fully pushing it on.
Reconnect the drive shaft to the yoke by lifting it into position and installing the two U-bolts and four nuts to secure the connection.
Tighten the bolts with the combination wrench. With the U-bolts tight, shake the shaft with both hands to ensure there is no slack between the U-joint connection and the slip yoke.
Remove the wheel chocks and drive the Silverado to ensure the noise no longer exists.
