I run a trans-go shift kit in my 1971 727. Had it now for 9 years. Manually shift all the time. Shifts as good today as it did 9 years ago. No more than I drive it, maybe 2,000 miles a year, the tranny will out last me. I'm old.

PS, if it's so hard on the transmission, why did Ma Morpar make it possible to manually shift from low to drive, and drive to low? Back when I was a kid, we manually shifted them things all the time. I don't remember anyone having transmission troubles.