This truck has been the best work truck I've ever had. the 5.3l vortec is an amazing engine. unfortunately it started to have a knock. I parked it immediately and have not driven since. I believe it is most likely something to do with the lifters or something that I am not willing to repair. I would consider it a parts truck or engine replacement at this point. 4 wheel drive works great and the truck still runs great other than the knock. I just barely put brand new tires on it that cost me $1400 and I also put new leaf springs at $500.00. I also replaced the head lights and tail lights last year. The transmission never gave me a bit of trouble and the engine still runs well, but the knock sound serious. from what I have researched it is probably lifters or something like that. still runs and drives fine.