'88 GMC Suburban 4x4 - approx. 350K miles and original transmission (routine hauling and trailering on family ranch)
'96 GMC Pickup 4x4 - 210K miles and original transmission (routine hauling and trailering on family ranch)
'00 C5 Corvette - 38K miles and original transmission (TONS of punishment)
'50 Split-window Chevy Pickup - approx. 140K miles, 54 years old, mostly original tranny parts but regasketed and rebuilt
That's just from personal experience with GM products in the immediate family...
I know of a few farmers/ranchers that are still running around in late '70/early '80 model Chevy Big 10s with original trannys and I think one or two still have their original engines. They admittedly aren't in the best of shape, but from personal experience I can attest to the die-hard character that most GM engines and transmissions have, at least on the V8 and truck side of the house.
