Rear brakes acting odd, grab extremely hard

98 w900 n14 13spd

So when Im empty of bobtailing, my brakes have been acting pretty weird.

When I go to apply them i gently push down, which doesnt immediatly grab, and then it grabs hard were myself will actually jerk forward a bit. Sometimes it sounds like a hard grind noise or a squeak when stopping. I guess some would referr to it as dump truck brakes?

I dont know what to look at first. The shoes are good and I keep the slacks adjusted, but I know they shouldnt grab as hard as they do when you apply the first little bit of brake pressure.

Anyone have any thoughts? This is on the drives. I orginally thought it was the steer axle so I had replaced the shoes, drums, slacks and air pods and nothing had changed which then I realized it was coming from the drive axles instead.