Hi Chris,
Need-A-Vacation wrote:
My "crazy" thinking for the 4.10's is that even though we recently stepped into our current tt, it will give us the option down the road to step up if we so choose since rated towing is 9500lbs vs 13000lbs, 3.73 vs 4.10, all else being equal. Not to mention being a little over 7k now, the added rear gear will make hills more laughable!
Empty I usually do up to 75ish, towing usually try to stay around 68ish.
Frankly, I wouldn't put too much stock in 4.10s magically allowing you to pull 37% more weight. 4.10 / 3.73 ~= 1.10, which means 10% more torque to the rear wheels at any given speed.
Another way to get more torque is by downshifting (i.e. changing gear ratio in the transmission). For example, my truck has 3.73s and spins at 2100 RPM in 5th gear at 62 MPH, which is the speed I usually tow. If I had 4.10s, I'd have 10% more torque at the wheels, but my RPMs would also go up 10% to 2300 RPM. Since my truck rarely needs to downshift out of 5th, I don't need that extra torque, but I'd still be paying the price of the extra RPMs 100% of the time.
When I need to, though, I can downshift to 4th and get 32% more torque at about 2800 RPM. I can also downshift to 3rd gear, giving me 77% more torque and still be at a comfortable 3700 RPMs. And I can even grab 2nd if I slow down to about 54 MPH (172% more torque at 5000 RPM). With 4.10s, I'd have to slow down to around 49 MPH.
Need-A-Vacation wrote:
Empty I usually do up to 75ish, towing usually try to stay around 68ish.
At that speed, my truck with 3.73s would spin about 4100 RPMs in 3rd gear. With 4.10s, about 4500 RPMs.
Bear in mind that if you're running ST tires on your trailer, they're rated to only 65 MPH.
-- Rob