[GoGoat]

I need to settle a discussion. Are most automatic transmissions (not overdrives) 1 to 1 ratio in high gear? Thanks

[b-man]

Yes they are 1:1 in high gear.

[steve25]

x 2 with the above in terms of what came in our era cars!
But the torque converter provides a increase of 2 to 1 in torque up it it’s stall speed, so even rolling along in 3rd gear ( 1 to 1 ) but at slow speed the car will have twice the torque output available if you stab the throttle as compared to a 4 speed in 4th gear all thing being equal of course!

[Formulabruce]

Even a Doug Nash 5 speed Standard is 1:1 in 5th gear....
Also, some " regular" automatics have a Lock up in high gear ( still 1:1 though)( TH350-C comes to mind)

[Schurkey]

Originally Posted by steve25

the torque converter provides a increase of 2 to 1 in torque up it it’s stall speed, so even rolling along in 3rd gear ( 1 to 1 ) but at slow speed the car will have twice the torque output available if you stab the throttle as compared to a 4 speed in 4th gear all thing being equal of course!

No. The maximum torque multiplication of a torque converter is just before the turbine begins to turn. The closer the turbine speed to the impeller speed, the less torque multiplication there is.

So even if the converter has 2.x times the torque multiplication, as soon as the turbine begins to turn (car begins to move) the torque begins dropping off.

[P@blo]

Originally Posted by Schurkey

No. The maximum torque multiplication of a torque converter is just before the turbine begins to turn. The closer the turbine speed to the impeller speed, the less torque multiplication there is.

So even if the converter has 2.x times the torque multiplication, as soon as the turbine begins to turn (car begins to move) the torque begins dropping off.

But there is still a mechanical advantage an automatic transmission with a torque has over a manual car. TCs are what is making these new electric super cars possible as they couple electric motors with torque converters to do wonderful things.

I read the multiplication from a torque converter is the initial take up before the car starts moving. First few feet type of deal but is still a multiplication factor (advantage) for that period.