The engine speed is exactly the same as an axle with ratio = OD × current axle.
.70 OD × 4.10 = effective 2.87:1
However, it's not the same in other respects:
1. you have some additional fluid pumping loss in the transmission due to the extra gearset (minor)
2. the driveshaft is still turning the same speed as always with the 4.10 - very fast, and this is a safety issue for very high speed cruising. Your engine will like doing 100, your driveshaft and U-joints won't.
