UPDATE 5/10/18 - PROBLEM SOLVED: Turns out the issue was that I forgot a bolt on my caliper when I replaced my brakes. User error! I have no idea how I managed to miss a bolt - perhaps it rolled away somewhere and I just completely missed it. The weird part is I could have sworn this issue started before the brake replacement... perhaps the bolt was missing at that time? Who knows. Either way it was definitely user error on my part - that bolt wouldn't just fall off on it's own. By the way, before learning about the missing bolt, I actually replaced my rear sway bar links AND sway bar bushings - all of which were bad, so it's good I replaced them.

----------------------------------------------------------------------------------------

I have an 08 Mazda 3, i Touring. When I go over a bump or minor crack in the road my front wheels glide over nicely, while my back wheels hit it way more roughly. To help put it in perspective, if I were to drive over a 1 inch pipe, my front wheels would feel it as you'd expect, but my rear wheels feel it like it were a 4 inch pipe. It's not just a noise being heard, this is something that is clearly felt as well. Riding in the backseat is noticeably more bumpy than in the front seat.

A year ago I replaced the rear shocks because when I'd go over a bump whilst turning, I'd momentarily lose traction because my rear shocks weren't bringing the wheels back down to the ground fast enough. The issue I'm now experiencing is different than that. I don't lose traction ever, it's just that going over bumps and cracks is much more intense than it should be. This issue seems to almost have gotten worse as time goes on, but it's hard to say for sure. I started noticing it probably 3-4 months ago.

I inspected the rear shock mounts and they are still in tact, no cracks (as I know this is a common issue with these mounts).

 

Most common is rear sway bar drop links, followed by upper control arm bushes.

 

I replaced both the links and the bushings, but it turns out my problem was that I was missing a caliper bolt on my rear driver side! User error on my part! Can't believe that.

Thanks for your suggestions though - my links were definitely bad, so I'm glad I installed the new ones. One of the links was completely siezed up and the other link had way too much give. New bushings were a massive pain in the butt to install. I couldn't get the new bushings on, so what I ended up doing was going to the hardware store to buy longer bolts so I could put the metal bracket over the bushing, and just screw the bracket in, little by little on each side, slowly forcing the bushing over the bar. I'll never do my own bushings again, it was way too much of a hassle. I'll just buy them off amazon and pay a mechanic to install them for me.