Hi everyone. I have a 1990 GMC Sierra 1500. It's rear wheel drive and for the past month or so, I've noticed that I'll be sitting at a light and all of a sudden I'll hear this loud clunk and it feels like if the truck got hit from behind. I thought it might have been the u-joints, so I replaced them both, but the problem still occurs. Now it's gotten worse. Even when I am driving at highway speeds, at random I will feel this hard clunk. It almost feels like something is binding up and lets go right away.
I am not sure what it could be. The transmission fluild is topped up, and like I said the u-joints are new. The drive shaft actually is only 4 years old as well, as are the gears in the rear end.
Can somebody please shed some light on what's going on here? I am not sure what to check on this one in order to figure it out. I am starting to worry that I'll be picking up pieces of my truck on the highway really soon.
