Montana :: 1999 - Front End Shifting On Right Turns

Pontiac van? Ours is a 1999. I had the trans rebuilt last year. The trans shop dropped the sub frame to get the trans out.

Had a front end alignment done last year too as I had the trans shop install a new rack (old one was leaking) while the sub frame was lowered.

Had to take the van in for an alignment and afterwards the steering wheel would not center. Plus, on right turns you could hear something shift a small amount and when the van straightened out, the wheel was in a different position as if the sub frame was shifting on the four bolts that attach it to the chassis. But the bolts and the isolators are tight.

The steering rack is bolted in tight, I've checked it. The front and rear bushings on the control arms are good as are the shock mounts. But the steering wheel will re-center to a new 'center' each time something shifts left or right.

I thought it was perhaps the front brakes making the noise and causing drag on the rotors causing a pull left or right, but after doing the brakes (new rotors and pads; old rotors were warped) it changed the sound a bit, but the sound and feeling that something is shifting is still there on right turns. Outer tie rods are new and tight, lower control arms are new and the shocks were replaced with quick struts around the same time as the control arms.

Is there any way to check for this sound and possible shifting, and what if any remedy is available to correct it?