I replaced the drums, shoes, springs on my '13 1500 Z71 (stock suspension) about 2 wks ago and it felt like I had a warped drum or even rotor on the front after everything warmed up. Front brakes were due as well, so I was thinking the problem was coincidence. New rotors and pads on the front was the next step, but the problem is still there. Definitely coming from the rear.

When I decelerate and brake above about 35 mph, I get a pretty noticeable vibration that goes away below probably 15 mph. It's not like a warped rotor where the problem is noticeable across the speed range. I've had the wheels and drums off several times, making sure everything is clean and installed right - clearly i'm missing something. With the rear en on jack stands I slowly rotate the wheels and did feel an intermittent brake drag on one side - removed both drums and exchanged for new ones, thinking I had an out-of-round problem with the drums (thanks, AutoZone - that was easy!).

Backing plate appears good; could it be air in the lines? No leaks from the cylinder at the wheel on either side. I thought I may have initially had one side snugged up too much in relation to the other, but that's moot with the auto-adjusters...right? I initially didn't feel any vibration in the brake pedal, just overall. But now I'm feeling it in the pedal as well.

Brand new tires and balance as well so that's out. I've even read there could be a tranny problem as it's downshifting, maybe a u-joint, something. But if I let the truck coast/decelerate (no brakes)...no problem.

I'm getting to wit's end here....thanks in advance for any ideas!