06 Rear end bucks when braking...what is it?

[Walker]

When coming to a stop, and applying what I would consider "normal" brake pressure, the rear end "slips, hops, bucks" a little. It feels like the type of "backlash" you'd get from a spinning reel. Like the rear end is trying to catch up or maybe slow down to match the stopping speed. Hard to explain, but I just have to glide or feather it down to a stop to keep it from happening. I've got the LS (didn't have one in my 01'); is this how they act?

 

[geusterman]

Brother Walker,

My gooseneck just did that tonight empty. The brakes were set too hard and it "bucked" the truck violently as I came to stops until I eased off on the electric brakes. I am guessing your rear breaks are coming on at a different rate than the front brakes. Not sure if that can happen but appears so. Brother George

 

[FJfonda]

Walker,

My 04. 5 suffers from rear brake rotor TV (thickness variation) which results in severe brake "surge" at slow speeds. Could this be what you are experiencing?

 

[TFucili]

I had similar symptoms on a truck years ago that turned out to be loose U-bolts.

 

[HOBrian]

Mine was a u joint.

 

[rjohnson916]

Is it a vibration, or more like a drive line thunk! or something similar? Mine does this every now and then. Mostly when I'm circling a parking lot looking for a spot. Scenario, will feed the Cummins a little just to roll the truck forward, but it doesn't act like a gasser, where the engine will rev with the roll speed and idle. The Diesel sends a surge of torque to the rear, but you are slowly still rolling and all that torque is still slowly rolling to an idle so it will buck the drive-train trying to divert the un-needed torque. I notice Super Duty's don't do it, they are really smooth because they don't make any torque :-laf



-Ryan