Hi, I’ve been learning about car mechanics recently and I would like to know how the automatic transmission’s one way clutches work. I know how the normal grab clutches work that are splined to the ring gear, and how they are actuated and what they do, but I can’t seem to quite understand just exact…

For this transmission, from the calculated kinematics of that carrier, it only wants to spin in reverse while accelerating forward in first gear. From 2nd gear onward, that carrier turns in the forward direction

Picture roller bearings around a ring in a cage to support them.turning one way, they roll like a bearing. Turning the reverse direction, the cage has ramps cut in it thst wedge the rollers against the shaft they surround holding it instead of acting as a bearing. Hard to describe but you must have…

I know how it works, about the oblong bearing idea and all that, but I don’t know exactly what it’s supposed to do, or where it is. Like I said, I know how the clutch packs and the bands work and how they are actuated and how it shifts the transmission, but the one way clutch is what gets me. I don’…

I think I heard about the freewheeling. There’s also the brake clutches which, when shifting with the gear lever in an automatic, makes an engine braking effect, I don’t think that happens in normal automatic mode though, only at higher speeds or something

I think it happens in higher gears… highway driving. The 6 speed auto un my car actually does allow some engine braking in gears 1 thru 4. That may only be in manual mode, I can’t evaluate automatic mode since it up shifts to 5th and 6th.

I think in manual mode it never disengages the transmission ever even when coasting, but when in automatic mode I do think it does. I could be wrong but that’s what I’ve seen in auto’s with a manual mode.

I have my custom TH400 set up with a reverse ordered manual valve body. It freewheels in all gears except final because it is manual VB and set up that way. It’s set up for drag racing, to reduce the possibility of blowing up the engine. All I have to do is let off the gas and it freewheels, the eng…

Most of the time, modern transmissions (like in the new Honda Accord) have manual mode with paddleshifters. Other modern vehicles have the DCT’s, but paddleshift automatics basically act like the older automatics with the 1st and 2nd gear selectors, but just with all the gears selectable instead of …

The Bands are holding the outer casing of a planetary gear set… which by design will provide different ratios…by either letting the outer case spin…or holding it in place and with clutches in the mix it can forcing the planetary to supply a gear reduction…or not… I’m not the trans expert but I do …

Ok, I think I get this. So the sprag clutch only works with the ring gear and nothing else? And also. from what it seems, the outer case is only there because it houses the clutch pack. So when that would stop spinning, the clutch packs that were on the casing would stop also, which would force the …

How does an automatic transmission's one way clutch/clutches work?

General Discussion

Mustangman April 22, 2020, 2:09pm 4

I know it allows the car to “freewheel” to reduce fuel consumption. Removes all engine braking allowing the car to coast. It is also used to redirect motion inside the trans but I have never studied automatics in any detail. Sorry, can’t help with that. While I have rebuilt manual transmissions, I have avoided automatics!

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How does an automatic transmission's one way clutch/clutches work?

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