rear axle ratio change better towing capacity

RCMAN46 wrote:

SoCalDesertRider wrote:

RCMAN46 wrote:
Changing the rear end ratio will not give the truck any more horsepower than it has now period!

If you have a newer truck with a six speed transmission changing the rear end ratio may change the gear you can climb a hill but most likely it will be at the same speed as before the change. Horsepower is what gets you up the hill and a different rear gear ratio will not change the horsepower an engine can produce.

Gearing is a torque multiplier. Lower ratio gearing (higher number, ie: 4.56) greatly increases torque available at the rear wheels, versus higher ratio gearing (ie: 3.55).

400 lb-ft torque x 3.55 = 1420 lb-ft at the rear wheels
400 lb-ft torque x 4.56 = 1824 lb-ft at the rear wheels

Lower ratio gearing also increases the rpm of the engine, at the same wheel speed. Most gas engines produce more horsepower at higher rpms. So yes, lower ratio gearing does increase the amount of available horsepower and torque at the rear wheels, at the same wheel speed, compared to higher ratio gearing.

You have neglected what a transmission does. If I want to increase the rpm of an engine to get into the peak horsepower range I simply go to a lower gear. I do not need to spend money on a rear end gear change. The modern 6 speed transmissions give all the gearing you will ever need for most highway towing.
And the 5.3 engine will not stress the drive-line system regardless of what rear end gear is used. It simply does not have enough horsepower to do so.

To bad it doesn't work that way "just drop a gear!" I hear this on here all the time! Yes a 6 speed auto does have the different ratios to make it tow a load easier at a certain speed/rpm, but the fact is that a gear swap will make the engine work less towing the same given load. That is why a truck with different axle ratios will have different tow ratings. No where in the owners manual does it tell you to drop a gear if you want to tow X number of pounds!