Originally Posted by MADDOG
OK, well I suspect either the steering wheel needs to be centered but if you are really experiencing a pull vs. just having to hold the steering wheel off center, I'd start looking at the track bar and end links. They do wear out and given your mileage, that's the first place I'd look.
Any play in the wheels when sitting on the ground? Either top to bottom or side to side? Any abnormal tire wear? Those are indicators of worn steering linkage parts.
No abnormal tire wear that I can see, and its about -10 celsius out right now, so I don't really want to be trying to jack the truck up until it gets warmer to work on. I'll get back with any answers as soon as I can do more investigating.