My yukon came with 3.42 gears from the factory..i switched them to 4.10's cuz a friend gave them to me..now he has some 4.56 that he doesnt need anymore and he wants $100 for them..only used them for a year and he traded in his truck so he put back my old 3.42's..what are the gains from going from 4.10 to 4.56? Its a pretty stock daily driver and mpg's arent anything i care about..

 

The math says it's roughly a 11% increase in torque with this change vs roughly 20% increase you got with the switch from 3.42 to 4.1.

It would go through the rpm's pretty quick I imagine