Tire Pull?

[PaHumBug]

So I took it to the place that specializes in 4x4 trucks and it wouldn't fit on their machine (!?!?!???). They said it was too wide, but my lift only widened the stance by 3 inches and my offset isn't anything crazy, I don't get it.

So anyway, I got a survey from the GM place that I had it at a few weeks ago, and I chewed them out. Basically it's pulling left no matter where my tires are (so far) or what road I'm driving on, so I'm not buying the road crown and tire pull theory. I got a call this morning from them asking me to bring it back in so they can move the tires back to where they were to see if it goes straight then. I'll be amazed if it does, because if I have a bad tire and it's making it pull, then it should pull right or left depending on what side the bad tire is on, but it will never go straight, right? Or am I all wet?