Dynas

I had a shop install the SR Lowering Speings and C&L Panhard bar for rear axle. They also changed all the struts, Rear Diff Fluid, and an alignment.
Now when I drive there is a humming sound. I noticed the OEM springs had rubber on them after they took them out and the upgraded ones didn't. Is this humming sound because of that? The sound seems to come from the rear axle. Any ideas.

proeagles

Humming sound doesn't seem like a sound the springs would make without the rubber isolators. Having said that, there could be a vibration sound mimicking the humming sound from the springs. In any event, there should be rubber isolators IMO on each end of the springs.