Jerry, correct on limiters. Some larger trucks in the class 6+ even if they have revs available, will not let a rig go over "72" mph as an example.
Just as most diesels have torque limiters. Back in the day with 400-500 lb ft of torque, max 6-1 ratio 1st gears, you might get 3000 lb ft out of the trans. With today's 10sp trans at 4.5 x 2 with a TC, 9-1, now multiply that by 1000 lb ft of torque, one has 9000 lb ft coming out of the trans in first gear. Hence why most manufactures have 1.5-12" gear sets. The 10.5s would grenade. We won't talk about the 8.5 in my 1500! Lol.
Marty