The owners manual states that the engine was designed for at least 200,000 miles with normal maintenance. Mine is pushing 90,000 and I use one quart of oil every 5000 miles or so.
That does not mean that things bolted to the engine will last that long. I've replaced the alternator, plug wires, fan clutch, fiberglass fan, and a few other minor items.
My Allison transmission also has the same mileage and has needed nothing other than scheduled fluid changes.