[Marlin42]

For awhile now my 99 Silverado makes what sounds like a slapping or loud tick sound when I put it in gear. If I'm leaving my driveway, I put it in R to backup and as soon as I start to move, it makes this sound. When I put it in D and start to roll it does it again. It doesn't do it all the time but it does it a lot. Also, I noticed when come to a stop at a light or stop sign and start to go again, it makes a another sound like a "rotating squeak". It goes away the faster I go but it's loud and embarrassing in the neighborhood. Could it be the U-joints? It's like it goes with the rotation of the driveshaft.
Thanks for any info.
Also, that "slap" sound is almost like an electrical short type sound. Really wierd. Obviously hard to explain.

 

[Jaymez]

U joints I believe.

 

[sierra954]

I have this same problem. Sometimes it's a few loud clicks as I put it into R, then a click or two as I shift into D. Somebody please help.

 

[acollins24]

My friend also had the same problem with his stickshift transmission on his Silverado. We had it sent to the mechanic and he told us that the U-joint had to be replaced. Does anyone know where we could find replacement pickup parts for this?

 

[mudboy]

Go under your truck with no strain on the drivetrain (wheels chocked) and push up and down and side to side on the driveshaft close to both ends. Concentrate by the u-joint caps and if you see the tiniest amount of movement, then they are shot. Go to your local auto parts store and ask for a u-joint for your vehicle, get any brand OTHER than brute force. Ideally greasable u-joints are what you want. Install teh u-joint to where you can reach the zerk fitting and grease it up every oil change.