Grit dog wrote:
I suspect neither of these reasons are the reasons why and that it's possibly related to the old chassis design still being used (chassis modifications maybe needed for 10 speed), but not likely. All the same though, it's likely just an economic decision and not a capability decision.
A class C would be more capable as a gasser F450/550 super C than an E450 Van cutaway. But normal C's on van chassis's are price point vehicles, comparatively.
My point wasn't that the 10-speed isn't capable (it is). It's that the rest of the current E-series driveline can't cope with the extra torque that would be delivered by the lower gearing in the 10-speed, so they'd have to limit power in those gears. The E-series is still using a Dana 80 housing with a modified carrier for 10.75" gears and a small-ish driveline. All F-series are now running the Dana M series axles.
BTW - Tuning and certification for the 7.3L is now common to the E & F-series over 14,000 GVWR (and Ford claims power levels are the same, only the certification method differs). Exception that fleets can select the "economy" tune in the E-series. There just isn't much advantage to stuffing the 10-speed under there unless they also upgrade the rest of the drivetrain. Which I hope they do. But they already previewed the 2022 changes, and it's limited to an smaller doghouse. No drivetrain changes were posted.