Forum Discussion

4x4ord's avatar
4x4ord
Explorer III
Dec 14, 2019

Super duty 10 speed gear ratios

Very similar to the 1/2 ton ratios. They are probably all excellent but my personal preference is that they would have left reverse as a higher speed. I think it was 1:-3.4 in the 6 speed

Super Duty
Gear Ratios
First 4.615:1
Second 2.919:1
Third 2.132:1
Fourth 1.773:1
Fifth 1.519:1
Sixth 1.277:1
Seventh 1:01
Eigth 0.851:1
Ninth 0.687:1
Tenth 0.632:1
Reverse -4.695:1

GM/Ford 10r80
1st 4.6957:1
2nd 2.9851:1
3rd 2.1462:1
4th 1.7690:1
5th 1.5201:1
6th 1.2700:1
7th 1.0000:1
8th 0.8536:1
9th 0.6892;1
10th 0.6357:1
Reverse - 4.8661:1
Tow Vehicles
  • FishOnOne's avatar
    FishOnOne
    Nomad
    Dec 27, 2019
    All I could afford wrote:
    I remember riding in the middle seat position between grandpa and grandma in the old Chevy 6.2 Liter Diesel, chugging along in the right lane and loosing speed on any inclines, as I watched the black smoke puff out in the mirror


    I remember hauling some cattle to the Houston Livestock Show and Rodeo in a brand new 1984 Chevy C30 Crew Cab with a 6.2 diesel. Talk about a turd struggling to pull that cattle trailer even pulling in 3rd gear and don't even think about pulling in overdrive.
  • Huntindog's avatar
    Huntindog
    Explorer
    Dec 27, 2019
    Me Again wrote:
    Huntindog wrote:
    4x4ord wrote:
    An interesting point when looking at the 10 speed in a new F350 vs the 6 speed in a 2015 model is this:
    The max rear wheel torque at 1600 engine rpm in low gear (disregarding parasitic losses) in 2020 with 3.31 final gears is:
    1050 x 4.615 x 3.31 or 16,039 lb ft.

    In 2015 the max torque of the f450 with 4.30 final drive in low gear was:
    860 x 3.97 x 4.30 or 14,681 lb ft.
    It is even worse than you state. In 2015, all of the big three limited TQ in at least 1st gear to protect the rear end. A 3.31 is stronger than a 4.30. GM has publicly stated that full power is now available in every gear.
    I haven't heard about the others yet.


    That thing about diff gear would apply to the 4.615 and 3.97 tranny gears, with the 3.97 being stronger that the 4.615?


    I don't know about the trannys.
    The diff is the last piece in the driveline, so it has to stand up to the multiplication that has occured in the tranny and convertor. The deal with taller R & P being stronger is that as one goes lower the contact between the R & P gets smaller and weaker.
  • All_I_could_aff's avatar
    All_I_could_aff
    Explorer
    Dec 27, 2019
    I remember riding in the middle seat position between grandpa and grandma in the old Chevy 6.2 Liter Diesel, chugging along in the right lane and loosing speed on any inclines, as I watched the black smoke puff out in the mirror
  • 4x4ord's avatar
    4x4ord
    Explorer III
    Dec 27, 2019
    All I could afford wrote:
    Even more torque multiplication available from the torque converter. How much trucks have changed in the the last 20 years


    The torque converter can double the torque output of the engine at stall speed but I'm not sure what the engine torque is at stall. By 1600 rpm there might not be much or any multiplication taking place through the torque converter.

    You don't even have to go back 20 years to see how huge the difference is in low gear rear axle torque. In 2007 Ram was still using the 48re transmission. The Cummins was detuned to 570 lb ft at the flywheel to protect the transmission. (The programming allowed higher torque output at times to account for power being consumed by accessories on the front of the engine). Anyway the 1st gear ratio of the 48re was 2.45:1.
    570 x 2.45 x 4.10 (final drive) gave an output of 5725 lb ft .... disregarding driveline losses.
  • Me_Again's avatar
    Me_Again
    Explorer III
    Dec 27, 2019
    Huntindog wrote:
    4x4ord wrote:
    An interesting point when looking at the 10 speed in a new F350 vs the 6 speed in a 2015 model is this:
    The max rear wheel torque at 1600 engine rpm in low gear (disregarding parasitic losses) in 2020 with 3.31 final gears is:
    1050 x 4.615 x 3.31 or 16,039 lb ft.

    In 2015 the max torque of the f450 with 4.30 final drive in low gear was:
    860 x 3.97 x 4.30 or 14,681 lb ft.
    It is even worse than you state. In 2015, all of the big three limited TQ in at least 1st gear to protect the rear end. A 3.31 is stronger than a 4.30. GM has publicly stated that full power is now available in every gear.
    I haven't heard about the others yet.


    That thing about diff gear would apply to the 4.615 and 3.97 tranny gears, with the 3.97 being stronger that the 4.615?
  • All_I_could_aff's avatar
    All_I_could_aff
    Explorer
    Dec 27, 2019
    Even more torque multiplication available from the torque converter. How much trucks have changed in the the last 20 years
  • Huntindog's avatar
    Huntindog
    Explorer
    Dec 27, 2019
    4x4ord wrote:
    An interesting point when looking at the 10 speed in a new F350 vs the 6 speed in a 2015 model is this:
    The max rear wheel torque at 1600 engine rpm in low gear (disregarding parasitic losses) in 2020 with 3.31 final gears is:
    1050 x 4.615 x 3.31 or 16,039 lb ft.

    In 2015 the max torque of the f450 with 4.30 final drive in low gear was:
    860 x 3.97 x 4.30 or 14,681 lb ft.
    It is even worse than you state. In 2015, all of the big three limited TQ in at least 1st gear to protect the rear end. A 3.31 is stronger than a 4.30. GM has publicly stated that full power is now available in every gear.
    I haven't heard about the others yet.
  • 4x4ord's avatar
    4x4ord
    Explorer III
    Dec 27, 2019
    An interesting point when looking at the 10 speed in a new F350 vs the 6 speed in a 2015 model is this:
    The max rear wheel torque at 1600 engine rpm in low gear (disregarding parasitic losses) in 2020 with 3.31 final gears is:
    1050 x 4.615 x 3.31 or 16,039 lb ft.

    In 2015 the max torque of the f450 with 4.30 final drive in low gear was:
    860 x 3.97 x 4.30 or 14,681 lb ft.
  • valhalla360's avatar
    valhalla360
    Navigator
    Dec 17, 2019
    4x4ord wrote:
    valhalla360 wrote:
    For the fun of it, I pulled up a gear ratio to speed calculator:

    With the ford 2.7turbo, 3.73 rear end, 4.86 reverse gear and 32" diameter tires...30mph is 5710rpm. Redline is listed as 5800rpm...Assuming you aren't running around all day in reverse, this shouldn't harm the engine.

    If you drop back to 25mph, it's a much more sedate 4750rpm.

    So even with the really deep granny reverse gear, you can tow (push?) at 30mph on occasion (at least theoretically).

    I'm still trying to figure out what scenario this makes any sense.
    - If you have any significant room that the slightest mistake doesn't put you into the ditch/wall, it's easier to turn the rig around.
    - If its a tight narrow twisty road where you can't turn around, you just increase the difficulty level 10 fold getting up to 30mph (regardless of gear ratio)

    Update: Looks like if you have the diesel, you are limited to around 20mph in reverse as the engine is governed at 3700rpm.



    I'm not 100% sure what the gear ratio was for reverse in 2017. 2020 6r140s have a -3.4:1 and I've seen values of both -3.12:1 and -3.28:1 for the 6r140 as well. I have the 3.55 axle ratio and I believe 34" rubber mounted on my 20" rims.


    search gear ratio calculator...you can plug in your exact info.
  • 4x4ord's avatar
    4x4ord
    Explorer III
    Dec 16, 2019
    It's not just the additional 4 gears that will make the shifting behavior nicer on the 2020 but the flatter power curve as well. I think it will be interesting to see if the fuel economy of the new Powerstroke improves any.

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