292,000 miles on my 5.3L 2007 Suburban LTZ. The engine runs great. Compression is great. I resolved the oil consumption issue so I don't have to add a quart every 1500 miles now.
Transmission was rebuilt at 202,000 miles. My wife broke the forward sprag in it. She has a really bad habit of putting it in drive while still rolling backwards then slamming on the gas. I kept telling her it was going to break the transmission but she didn't believe me. The 4l60e is is a bit slow fully engaging drive after shifting from reverse. I rebuilt it myself and the internals were in perfect condition. Everything was well within spec and I have no doubts it would have gone 500,000+ miles no problem. I could have replaced the sprag assembly and put it back together as is but I did a full rebuild with all new steels and clutch packs. Also did some other upgrades so it's a 4l60e/4l65e hybrid.
What did you do with the oil consumption... I am down 2 quarts every 3000 or so miles...