I don't know about his comments on the longevity on the transmission, but the big maintenance item to look at on M117 and M116 V8's is timing chain and timing chain guide rail / tensioner rail replacement.

These engines are sensitive to timing chain wear, and most recommend replacing the timing chain, tensioner, and the respective plastic rails every 100,000 - 120,000 miles or so.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".