Change from 4-speed to 3w/OD

Again, you are technically correct. But a T56 won't grenade itself at WOT in 6th gear.

Only a matter of horsepower, you can grenade anything with enough juice. Put 1,000 hp in front of it and you can lunch a T56 too. Still a 6 speed, just like the 833OD is still a 4 speed. Has no effect on what you call it.