I have been able to find the final drive ratios for the 6r80, but im wondering what the internal gear ratios are that are used to come up with the final drive ratios for each gear.

on the face of it, it looks like they are using an under/over gear in front of a wide ratio 3 speed, but i cannot for the life of me figure out any set of internal ratios that make sense with what i know about planetary gearsets.

i must be missing something pretty obvious, though, because GM's 6speed gear ratios are nearly a spitting image of ford's.

just wondering if anyone knows how they are getting the gear ratios they have.

thanks!

 

It is not an under/over in front of the three speed. It is a "true" six speed. I don't have the information on the planetary gear tooth counts. That's trivia that I never needed to know.

 

Mark,

thanks for the reply! Knowing it is a true six speed explains why i couldn't figgure out any combinations of over/under driven gears to make the 6.

I noticed that they have gone away from a 1:1 gear. I'm just wondering if there is any down side to not having a direct driven gear. I was always under the impression that running in a gear that is not 1:1 will build more heat. Perhaps that is not always the case?

 

Running a gear other than 1:1 will ALWAYS build more heat. Depending on how efficient the gearset is the additional heat may be negligible. Compared to the heat that a torque converter generates it IS negligible.

 

just wondering ...

i found a video explaining the power flow for GM's 6L80. i'm wondering if Ford's design is similar.

i noticed the guy makes reference to the 1st gear sprag, which was an upgrade for 2011 in the Ford. i guess the main reason i ask is because the gear ratios between ford's 6r80 and gm's 6L80 are so similar it is spooky.

kinda long and perhaps dry, but it is really neat to see how this was put together.
GM Hydra-Matic 6L80 / 6L90 Power Flow - YouTube

 

Gear Ratios
Power is transmitted from the torque converter to the planetary gearsets through the input shaft. Clutches are used to hold and drive certain combinations of gearsets. This results in 6 forward ratios and one reverse ratio which are transmitted to the rear planetary ring gear (output shaft). The planetary gearsets of this transmission provide the following ratios:

Reverse:
Front planetary gearset ratio of 1.52:1
Rear planetary gearset ratio of 2.24:1 (reverse direction)
Total ratio of 3.40:1 (reverse direction)
1st gear:
Front planetary gearset ratio of 1.52:1
Rear planetary gearset ratio of 2.74:1
Total ratio of 4.17:1
2nd gear:
Front planetary gearset ratio of 1.52:1
Rear planetary gearset ratio of 1.54:1
Total ratio of 2.34:1
3rd gear:
Front planetary gearset ratio of 1.52:1
Rear planetary gearset ratio of 1:1
Total ratio of 1.52:1
4th gear:
Front planetary gearset provides ratios of 1:1 and 1.52:1 to different rear planetary gearset members
Rear planetary gearset ratio of 1.14:1
Total ratio of 1.14:1
5th gear:
Front planetary gearset provides ratios of 1:1 and 1.52:1 to different rear planetary gearset members
Rear planetary gearset ratio of 0.87:1
Total ratio of 0.87:1
6th gear:
Front planetary gearset ratio of 1:1
Rear planetary gearset ratio of 0.69:1
Total ratio of 0.69:1

 

Here is a good video of an actual 6R80 out of a 5.0 Mustang.