What goal are you trying to achieve?So does the combination of ECT + S5 replace the need to spend a few grand on new gears? I realize everyone's answer is different based on what their goals for the individual rig are. I am simply asking if one could come close with what I have listed instead of opening up the diffs.
Compensate for a tire diameter upgrade? Get more torque for climbing hills? Slower hill descent for control offroad?
I don't think ECT in any way results in the same or similar outcome as regearing, but others know more than I do.
I think about it like this:
Each turn of the crankshaft times the transmission gear ratio times the transfer case ratio (hi 1.0/low 2.618) = turn of driveshafts, then you multiply that by transfer case ratio to get the resulting turns of the drive axles (and thus the wheels)
For every 1 turn of the crankshaft:
1 x 1.51 [fifth gear] x 1.0 [high gear transfer] = 1.51 x 3.30 = 5.00 turns of the axles/wheels
1 x 1.51 [fifth gear] x 1.0 [high gear transfer] = 1.51 x 3.90 = 5.87 turns of the axles/wheels
So to cover the equivalent distance (get the same speed), you will run at lower RPMs with the higher numeric ratio (called a lower ratio for some reason). And it feels more "torquey", seat of the pants...
It gets even more dramatic when you look at what it does in the low gear transfer since everything gets multiplied by 2.618 before it gets to the drive shaft.
Let's look at 2nd gear low:
1 x 2.81 [2nd gear] x 2.62 [low gear transfer] = 7.39 x 3.30 = 24.46 turns of the axles/wheels
1 x 2.81 [2nd gear] x 2.62 [low gear transfer] = 7.39 x 3.90 = 28.89 turns of the axles/wheels
Offroad, pragmatically speaking, this translates into more torque, climbing ability and helps control descents better.
Shifting into 5th gear S, just keeps the transmission from shifting above that 1.51 ratio.