I have a buddy who has a 99, z-71 5.3 with 3.73, and a 141k, from day one it had a slight piston slap, it worried him at first but it only happenes for about 5 sec. on cold start ups. He refuses to trade in this truck, even with all the incentives or 0% financing, he has had no problems with it. My 2000, z-71 5.3 4.10 never had any problems other than a hic-cup a few times on the tranny, but towed my light construction trailer, 8500 pds around town. I leave the 10k trailer for the Pwerstroke Excursion, and my dailey driver is a Crew cab Duramax. I tow my 12k Thunder with that. Ford is great, but I have had better luck with Gm especially on longevety of parts and material wear, like seats and so on.