2005 Tahoe with 5.3, purchased new, 192k with original drivetrain. I've seldom towed anything with it, a few vehicles and utility trailers, but always in "3" with tow/haul mode. Actually, i always drive in "3" (loaded and unloaded) until getting on the highway. Its always been driven conservatively, never hotrodded. At 60k when i did the first pan drop and filter change, i installed a drain plug on the trans pan. Ever since then, i've dropped and replaced the fluid in the pan (about 1 gal) at every 5k oil change interval. I do my own maintenance, this adds very little to the maintenance expense and is very simple to do. Have also continued to drop the pan and repl internal filter every 60k, so this has been done 3x now. I've never discovered anything more than a minimal amount of shavings etc in the pan. In my opinion, the Tahoe still drives about like it did when i bought it.
