Accleration rattle on my '96 Silverado

I have a '96 Z71 with 196,000km that has been well taken care of. But recently, everytime I accelerate, even just a little, there is a rattle noise that seems to be coming from the back. It seems to occur after driving for about 5-10 minutes, after some stop and goes at intersections and such. We took a look at the exhaust system, everything's good there. The sound can only be heard in gear, not in neutral. I've heard this might be an inherent driveline problem and you have to replace the 2 piece with a one piece, but others say its loose or backed out torque converter bolts or a starter that has a loose or stuck bendix and actuator assy. Pls help b/c this goddam noise is driving me nuts!:banghead:

I have seen both the torque converter and the drive shaft do this so its hard to nail down without being able to hear it. Also look for broken leaf springs or shocks.