Agree with most of what you are saying. Travel for a living and have looked at many hundreds. Have also spent hours with fleet and could not substantiate the rear axle weight ratings for this specific combo. Had more than one start with confidence and end with an "I'll have to call you", but they never do. Had Ford customer service (contact from build site) say they don't know and I'll have to contact "someone" from engineering. For your screw the screw and even the long bed the numbers are there. Look at the short bed extended cab and you'll see none of the numbers change except a tow rating increase to 11,100 pound. On the other combos, that much tow rating increase corresponds to a payload increase. Just not clear in this case.

Conversation tends to go like this. I'll ask to run the build with 3.55 and 3.73. When they come back with the higher payload and tow with 3.73 I'll then ask "How can payload and tow ratings go up but your chart shows the GAWR stays the same?" I get a curious look and a response something like, well that's not right. I'll say exactly, please tell me where the error is so that we don't have to wait for the truck to show to find out.

I'll find out before I lay out the cash, however, either you are correct and the GAWR stays the same or they are correct that the payload goes up. Both can't be true.

 

Off the top of my head (so possible there is an error here) but the F150s have tremendous range in capability so you better know what you're buying.

• Payloads from <1,500 to >3,000
• GVWR from ??? to 7,850
• Tow ratings from 5,000 to 13,200
• Three different frame thicknesses
• Five different rear spring options
• Three different axles (8.8, 9.75 & 9.75HD)
• Wheel bases from 13X" to 16X"

It seems some "half tons" are more like 3/8th tons with running gear that is set up to compete with SUVs in comfort and MPG
Some "half tons" are true to the name
Some "half tons" are more like 5/8 tons and in some ways even rival or exceed the capacities of 3/4 ton diesel (specifically in payload)

The same half ton isn't going to be the MPG or comfort king and at the same time the payload or towing king. They are different trucks.

More than ever, you have to know exactly what you're buying in a half ton.

Someone else already mentioned that Ford has it's own version of the "heavy half" called the HDPP. They did seem to be order only for a while and now you can find some on lots. I bought mine off a lot 45 miles away after a lot of searching.

 

Gladehound, there are some here who say no matter what do not get the 3.5TT with 3.73 rear diff. How do you like yours ? Do you wish you had the 3.55 or 3.31 ?

 

I love the combination of the 10-speed with the 3.73. It was never a choice really, you can't get an HDPP with anything other than a 3.73.

I'll give you my subjective and objective experience below and you can judge for yourself based on your taste and expectations.

In 10th gear (triple overdrive) it is running 1480 RPM at 60MPH with 275x65-18 OME tires (calculated and consistent with tach). I have ~1,300 miles on my truck and have a life time (3 weeks) average of 18.0 MPG including some towing in the last 300 miles. I've gotten as high as 22.1 MPG on a 100 mile round trip and think it can do better because that wasn't an ideal trip for MPG. *Note - all MPG figures are from the computer so take with a grain of salt. It is smooth and quiet at any speed I've driven (up to 80mph). I never ever have wished for higher or lower gears (the 10-speed is a flexible transmission that would probably make any rear gear look good in any application)

Since I bough mine off the lot, I had the opportunity to test it to make sure it was smooth and quiet. I've ordered vehicles before only to find there was a driveline vibration at a certain speed. So I try to buy off the lot when I can. My point is, I cant guarantee all 3.73s will be as smooth as mine. Maybe I got lucky or maybe they are all like this.

If I could have chosen any rear gear I wanted, I still would have went with the 3.73. I think it is better in a towing application with the 3.73 because it puts less stress on the transmission and keeps the engine at lower boost. As a daily driver, I've also found it to be flawless.

 

I will add that a 3.73 will give you a little more idle torque when you want to creep without touching the gas pedal. This is good when hooking up a trailer or maneuvering in tight spaces in uneven terrain. Even with the 3.73 I'd like a little more idle torque so absolutely wouldn't want a lower numbered rear than the 3.73.

For someone running empty all the time, who never uses their truck as a truck, maybe there is a benefit to a lower number rear even with the 10-speed. Not sure. You'd have to talk to a person like that - not me.

 

I will add one more thing for you to think about. Due to the 0.63 ratio top gear on the 10-speed compared to the 0.69 top gear on the 6-speed. A 10-speed with 3.73 is the equivalent of 6-speed with a 3.41 in terms of combined top gear ratio and cruising RPM. Out of the options that are available, that's closest to a 6-speed with the 3.31.

 

I think you have the numbers wrong.

A 10sp 3.31 is equivalent to between a 3.55 and 3.73 on the 6sp.

3.73 on the 10sp is closer to maybe a 4.10 on the 6sp.

 

I am not wrong, and you are not wrong either - thus the flexibility of the 10-speed.

Comparing top transmission gears, what I wrote is absolutely correct. If you want to compare the 1st gear ratios it works out like this...

10-speed 1st gear 4.69:1
6-speed 1st gear 4.17:1

So in 1st gear, a 10-speed 3.73 is like a 6-speed 4.20:1

 

I replied to this thread already but my post didn't show up. Maybe the moderators haven't approved my post yet.

I have a 2016 SCab 2.7L 8.8 rear axle w/ 3.73 ratio, locker and electric parking brake. 3.73 gears does not require the 9.75 axle.

 

I actually wonder if there are cases where the factory decides to put on what they have even if what they have isn't what they may normally spec. For example, if they have an order for a 2.7L with 3.73 and they typically build this with the 8.8 but don't have any 8.8 on hand with the 3.73. Maybe they put in a 9.75 if they have it there. Nobody is going to complain about getting the beefier axle.