It's been a couple of weeks since I've been on this thread.
Truck has spent most of it's time at dealership. New Pitman arm TSB "D", better but still not right, truck had a readylift kit, keys, UCA's and shims, I've removed all of that and now it's stock and still on level hwy drives like a boat.
I put a little starboard input in wait for the helm to answer and then put a little port in and wait...last weekend drove about 300 miles all hwy what a PITA!
So, went back to dealership drove a 17...OMG night and day difference, drives straight no wandering on hwy....I'm going to shoot for a new steering box, if that doesn't fix it I'm gonna get rid of it and buy a FORD!
I've tried driving with Stabilitrak off, tow mode on (better) but loose steering still present. Input on steering wheel is not uniform, very loose at 12 position, but stiff if I move to 11:30 or 12:30 position. Let go of wheel on rough road steering wheel rotates back and forth on it's own. Tap the brakes, steering wheel moves?
When they removed the original pitman arm the tooth at the 12 position was worn in half, they changed the fluid in the steering box, but my thought is where did all the metal fragments go from the pitman arm...I'm thinking that whole hydraulic system is contaminated making inputs on the wheel inconsistent...I'll keep you posted!