true, and you can correct me if i’m wrong but a 10spd can’t take the big power & big tq.
as i recall when i bought my truck, she was turned up as much as she could be. C-15 @ 475hp 1650tq. That was because of the 10spd it had in it.
when i installed the 13spd i also added a trans cooler and now have since had the truck turned up.
again like you said, i didn’t need an 18, so i went with a 13spd.