My M5OD-R2 trans came out of what I considered to be light duty F250. It was a 1991 F250 2wd with 302, 5spd, and 3.08 diff. I've told the story before, but the guy was doing a Cummins swap in the truck, so he had the engine and trans for sale...but since the truck was an F250, he had the trans listed for sale as a ZF5. He said people kept messaging him to tell him the trans he had was not a ZF5, so he relisted it as the M5OD, and that is when I found it...only a half a mile away from my office, right here in the industrial park.
Yep, the non-HD F250's had a lighter duty driveline. I was not aware of that until I got Big Blue and noted the HD designation. Then I started looking for the LD's.