this weekend i put new the new springs, shocks, endlinks with poly bushings, lca's, lca relocation brackets, and panhard bar on my car. it handles great, but now i have a loud humming/whining noise when i hit crusing speeds of 35 and above, it seems to be the loudest when i am on the gas at those speeds, if i let off the gas it gets much quieter, but under acceleration it is louder. I think my car had this noise before, just much much quieter. I'm pretty sure its a drivertrain issue because if i put it in neutral at crusing speeds and rev the engine it doesn't produce the noise. I don't know if it is a "bad" noise, i just can't figure out what accounts for it. I don't think poly bushings or the lower springs would account for it.

any ideas?

 

Rear going bad? The poly bushings probably just made more of the noise transfer the body of the car making it sound louder. That’s my bet.

 

Mine makes the same noise. It sounds like the rear end to me to. Mines been doing it since I swapped rear ends in the car about 20k miles ago.

 

yeah it is weird, the more i listen to it the more i find out about it, for instance, it is loudest between 40-50 mphs, so if it is the rear, what actually causes this noise?

 

Mines worse around 40-50mph also. I think it's from improper gear setup when gm put these things together.