We have the 3.5 n/a v6. The ptu is on borrowed time for sure, and has been for a while. I crawled under it a few years back to change the fluid, and it was more like face cream. I extracted what I could and filled it back up, which was about 140k miles ago now. I've been nursing it along ever since, with fluid changes and fills. But it just recently started leaking on the seal against the trans so I'm going to have to be far more active with fluid monitoring now.
Water pump is still original. I did have a belt tensioner fail about 80k back, but that part was all of like 30 bucks and took me an hour to replace. Everything else has been maintenance item stuff. We typically get 75-80k out of a set of brakes, and 70k from tires. I change the oil with Royal Purple every 7-10k, trans is amsoil, ptu is royal royal and the rear diff is redline fluids.
Last year I replaced the shocks, struts and mounts, and this year I did the lcas. The front subframe bushings on the passenger side are worn out now, but I need to buy the tool for that and schedule some lift time for that job. Overall it's been a good truck, and my wife is NOT easy on it. Plus we take it 8-10 miles up the beach on loose sand, over the dunes every now and then, and rowa travel trailer with it.