4-Speed Auto or 5-Speed AUTO?

[Rogue]

Those of you who drive C4's, how many ratios do you have in your tranny?

From a standing start, I count 5 ratios, that is, 5 times the engine drops its RPM from take off. I know the 5th drop is the overdrive from 4th gear but since it drops the RPM, doesn't that count as a "speed", if not a "gear"?

So why call it only a 4-speed automatic? What it really is is a 5-speed automatic since it has 5 ratios to choose from (but not necessarily 5 gears).

I remember other manufacturers did this when they first came out with their "5-speed" automatics. They just added an intermediate "gear" by having the torque converter partially lock up in one of the middle gears.

 

[vader86]

You only have 4 gear ratios to choose from in a 700r4.

You might be getting fooled by TC lockup.

 

[Ken]

It's the lockup converter alright.

 

[Rogue]

I know it's the lockup. It's function is to lower the RPM, which it does.

I'm just wondering out loud why not call it a 5-speed autobox. Because in effect, it has 5 ratios that it goes through. Although NOT 5 real gears.

 

[drags1998]

Rogue, the transmission has 4 speeds only, the converter lock-up feels like another gear but is not. Now,Please ,No hate mail on this one. My Dodge Dakota has a 4.7 and a 5 speed Auto. It is a nice working tranny,but has some odd habits. It has what dodge calls 2 Third GEARS. one third gear for up-shifts,the other3rd gear is for down-shifts. I have no idea why they did this,but it works well!!!!! Paul:confused

 

[Grizzly]

Actually it has at least five ratios, but you all are thinking about the converter lock up. Any torque converter has some ratio associated with it at stall. In my 92 it is 1.85 to 1. That means at launch the actual ratio is 1.85x3.06 or 5.661. That starts to drop away as soon as the rpm picks up but you still have it at launch to get things off dead center. So first gear is variable from 5.661 down to 3.06.

Check some old Road and Track Road Tests, it's always listed. A 64 300hp 2 speed powerglide was slightly faster up to 50 and only 3 seconds slower to 100 than a 67 300 hp 4 speed with the same rear. Why, because at stall the pg had a 12:1 ratio when the 4 speed had 8:1 A lot of people are surprised how quick the old pg cars are off the line.

 

[Rogue]

Rogue, the transmission has 4 speeds only, the converter lock-up feels like another gear but is not. Now,Please ,No hate mail on this one. My Dodge Dakota has a 4.7 and a 5 speed Auto. It is a nice working tranny,but has some odd habits. It has what dodge calls 2 Third GEARS. one third gear for up-shifts,the other3rd gear is for down-shifts. I have no idea why they did this,but it works well!!!!! Paul:confused

This is exactly what I'm talking about.

I read about this tranny. Dodge says it's a "5-speed auto". Well, it does have 5 ratios. But only 4 real gears. The electronically controlled Torque Converter has a partial and full lockup feature in certain gears. Third being on of them. This is how Dodge came up with 5-speed auto designation.

Lexus did the same thing not too long ago with their autobox. They took their "old" 4-speed auto and gave it an computer controlled partial/full lockup torque converter, which gave the tranny its "5th" gear. The 2nd gear actually came from partially locking up the torque converter after 1st, or something similar.

Anyway, my point is, you guys with autos, count how many times your tranny shifts from a start. From take off it's in 1st gear. Then count 2,3,4 as it shifts up and the engine drops RPM's. You will count 4 ratio drops, plus 1st gear. That's 5 speeds to me.