4.88 gears first tow - Huge!

After breaking in the the new set I had my first opportunity to tow. The load was was about 3200 lb including the trailer. The route took me up hill from about 500' to 2800' over 50 miles. The first 20 or so miles was a very gentle climb. Several spots had passing lanes because it was steep. I drive this routinely and have towed before. The route is posted 55 mph but traffic will move at 60 mph.

1st and 2nd gear - There is a very noticeable change as torque has increased. You go through these quickly in about 10 seconds and at about 30 mph, 3248 rpm you move to 3rd gear.

The trick now is when you move to 3rd gear you start at 2316 rpm not the old 1855 rpm. You are higher in the engine's power band. And if you have your foot in it moving to 3rd gear will be delayed as you push the rpm up towards 4,000 rpm or more.

Here is where I saw the huge difference. At 60MPH. The only way I could get enough power to hold the speed in the past was to run at it in 3rd gear at 3710 rpm. Now I am in 4th gear at 3108 rpm and I have some extra power without shifting down. But here is where I saw the big difference, at 3710 rpm the transmission wants to shift to 4th gear so it ping pongs back and forth between 3rd and 4th. In 4th gear the rpm drops to 2490 rpm too low to get the needed torque so you press harder and your back in 3rd. There were two spots where I still needed to drop into 3rd and I let it wind up to 4246 rpm to hold 55 mph. Note max torques is speced at 4600 rpm. Before I might have been in 2nd gear going about 45mph

ECT - I never used the ECT it just was not necessary. Also played with just leaving it in drive and manually with the sport mode.

Notes; I am running 265/75R16 tires so they are just 1" larger diameter. The net result is the 4.88 gear has a real effect to be a 4.73 Gear. If you run even bigger tires the gear will get closer to the stock number. One more note at 75 mph rpm is 2681 in 5th and 2254 in 6th.

I am still glad I did this.

2016 TRD OR Auto Trans

 

Per the manual, you're supposed to turn ECT on when towing, it adjust shift patterns and holds gears longer. Just fyi.

 

ECT does not change the RPM vs speed. The gear change lowered the operating range of the transmission relative to the ground speed. It also raised the amount of torque applied to the ground at any given speed. What I noticed that is important is for a given speed I can now get more power from the engine in the right gear.