Lets take it down to straight math ( no fancy college **** needed)
The underdrive can add lets say 10%...
That may make the math out for the 3.55:1 final lower than the 4.10:1, however now the torque multiplication is before the drivelines u joints (who now become the weak link) .
Gearing the selectable choices to match the final drive ratio of both differential carriers equally shows the added reduction of the 4.10 gives more usable grunt not available in the 3.55's.
Fwiw
This is real time stuff, in the ( toyota tech in my example) 4x4 's you can double the transfer case to "double the reduction " so guys take the 2.7:1 reduction housing gear, bolt it in front of the t case ( in effect an underdrive) using an adapter housing tween the case and reduction housing with a coupler joining the shafts inside and add in a 4.7:1 gear.(more grunt) to th rear case.
Now 2.27 feeds 4.7 to the drive line.
So trans torque bumps up by 2.27 then 4.7%. Linearly ...
Guys could buy the front gear reduction housing with 4.7's or 2.27's.
Problem putting a 4.7 in front of a 2.27 rear caused the coupler to frag...
Spike in torque input.
Ymmv
I'd much rather have a 4 speed brownie but I digress...
Thinking the 3.55 final works for the slushbox in your application is correct, however there's more math out there I know.
Someone can check my highschool math for inaccuracy .
Carry on
The underdrive can add lets say 10%...
That may make the math out for the 3.55:1 final lower than the 4.10:1, however now the torque multiplication is before the drivelines u joints (who now become the weak link) .
Gearing the selectable choices to match the final drive ratio of both differential carriers equally shows the added reduction of the 4.10 gives more usable grunt not available in the 3.55's.
Fwiw
This is real time stuff, in the ( toyota tech in my example) 4x4 's you can double the transfer case to "double the reduction " so guys take the 2.7:1 reduction housing gear, bolt it in front of the t case ( in effect an underdrive) using an adapter housing tween the case and reduction housing with a coupler joining the shafts inside and add in a 4.7:1 gear.(more grunt) to th rear case.
Now 2.27 feeds 4.7 to the drive line.
So trans torque bumps up by 2.27 then 4.7%. Linearly ...
Guys could buy the front gear reduction housing with 4.7's or 2.27's.
Problem putting a 4.7 in front of a 2.27 rear caused the coupler to frag...
Spike in torque input.
Ymmv
I'd much rather have a 4 speed brownie but I digress...
Thinking the 3.55 final works for the slushbox in your application is correct, however there's more math out there I know.
Someone can check my highschool math for inaccuracy .
Carry on
