ITi s a GM Vortec on a Workhorse chassis. The alignment was done by a well liked truck repair shop in RI and I will ask them the questions you asked me, if they checked the steering components etc. It was done on a special machine that is supposed to be the best for alignments of trucks and RVs. They are VERY accommodating so will ask the questions. The Safe T Plus cost me about $600 installed so would like to not go another $600 for rear stabilizer but will look into it but will have total steering mechanisms/front end checked first to make sure it is not the cause. NOT sure why they did not put the steering wheel on straight after alignment but also not sure it was not straight until the Safe T Plus was put on and they did test it muliple times to get it not to pull one way or another but still pulls to left a little if I let go of steering wheel. THANKS ALL FOR YOUR SUGGESTIONS AND HELP!!