So now that I got the tdi, the IDI's have been seeing a little less daily driving (although when it rains I've been driving the 6.9 and it rains almost every day here so not that much less) and the other day I had something happen before I've never had happen ever in any vehicle and I'm super confused. This is on my 85 F350 4x4. I was pulling out of a intersection and at the stop sign as you pull out you were facing downhill pretty steep. As I turned left and shifted into third gear, the truck started pulling pretty hard to the right quick enough that if you let off the steering wheel it would have took you off of the road. I just held it at center and it didn't seem like it wanted to let up, so I "jerked" it to the left and then it started to want to go that way but not quite as strong and I was trying to think what could this be? And as soon as that thought came into my head, the issue just went away entirely. The truck just had it's annual PA safety inspection where wheel bearings, excessive axle play, and tie rods and the like our checked over. Nothing seems awkward on the truck looking at the front end. It just was aligned a year ago when I got new tires. I did hit a deer on that side of the truck but all it did was dent the bumper pretty good (got a new one) and now I have only had this happen twice in over 3000 miles. Both times turning left. What am I missing here? steering box isn't falling out, steering shafts are still bolted in good. Tiny play but nothing weird. Lug nuts still tight. I don't notice any u joints that look unhappy and there are no vibrations or noises at all. I jacked the whole front end up and tried to wrestle both tires around in any direction to feel play and there is nothing.. I had wondered if a brake caliper was sticking the first time it happened and then it didn't happen again for two months until the other day when this happened. I tried pressing the brakes and it stopped evenly so I tried the turning left thing. It's not just sloppy steering play though the truck doesn't have sloppy steering at all and it feels like it's bad alignment pull, but the fact that it can go away for a month and not do it makes me think it's something else. So confused.