One problem related to front suspension control arm has been reported for the 2000 GMC Sierra. The most recently reported issues are listed below.
I had the dealer do a schedule tire rotation, and on they way home I reached the speed of 40 mph the truck started to shake like I was going over speed bumpers. This stopped but the front end still bounces when ever you go over a series of small bumps the whole front just shakes you have to use two hands to keep the vehicle in control, don't use the brake the pedal goes soft until you are out the rough road. I have had the tires replaced and but new rims on the vehicle. The bounce is still noticeable at speeds over 40, the road does not change the effect. The crowning of the road is not the problem. The dealer says the front is tight and can not duplicate my problem so they can not fix it. The service manger says I've lowered my front end this GMC Sierra is totally oem exc for tire, and aftermarket dress. I had the truck aligned and the thrust angle was off so my son-inlaw and I did a thrust alignment first and the front end alignment. Also one of the upper control arm bolts was slightly loose, you could see the brown rusty powder around the bushing so this was loose for some time. I am a diesel mechanic so I know there is something wrong loose, or worn out that needs to be done to correct the problem, things do wear out and I do not mind paying for things to be done correctly.