How an Automatic Transmission Works

[geokilla]

Part 1

Part 2

Great video explaining how automatic transmissions work. Too bad I don't really understand it.

 

[BUTCH1]

Very interesting, gave a good basic description of what's going on. Looks like he's running a salvage yard at that location as well, hope if he is doing rebuilds it's in a cleaner area!.

 

[geokilla]

Did you check out his other videos? Some of them were pretty funny and interesting as well.

 

[CurseTheSky]

He's not the greatest speaker in the world, but he does a good job explaining it. I've known how manual transmissions worked since I started working on cars, and I always assumed automatics were similar (just with some way of automatically selecting a gear). Man was I wrong.

The coke nail on one of his pinkies kept throwing me off though. =/

 

[BlahBlahYouToo]

so is the fact that the gears are always engaged in an auto the reason why it gets worse fuel economy than a standard?
the extra friction?

 

[overst33r]

Originally posted by: BlahBlahYouToo
so is the fact that the gears are always engaged in an auto the reason why it gets worse fuel economy than a standard?
the extra friction?

Most of the losses are associated with the torque converter itself as I understand it.

The reason is because the torque converter does not lock up at all speeds. It's spinning at a different speed than the flywheel and therefore does not transfer all the energy of the engine through the transmission to the wheels. Most cars nowadays lock up the converter >25mph to minimize these losses.

BTW, the gears in a modern manual are also always in mesh. Only one of these meshed pairs of gears is locked to the shaft on which it is mounted at any one time, while the others are allowed to rotate freely.

 

[The Stigenator]

i learned a lot..

didnt know i had to check tranny fluid with the engine on.. i am off to check that on my mom's car.

 

[Vortex22]

Originally posted by: CurseTheSky
He's not the greatest speaker in the world, but he does a good job explaining it. I've known how manual transmissions worked since I started working on cars, and I always assumed automatics were similar (just with some way of automatically selecting a gear). Man was I wrong.

The coke nail on one of his pinkies kept throwing me off though. =/

According to Wikipedia, Honda auto transmissions actually do work this way (similar to a manual), I didn't know that.

 

[AdamK47]

What's up with his pinky nail?

 

[Kaervak]

Ah Davesfarm, tons of crazy Canadian redneck videos and how-to-fix-it videos. Lots of good stuff from him, definitely worth a look around in his video section.

 

[CurseTheSky]

Originally posted by: AdamK47
What's up with his pinky nail?

See my post above. I'm giving him the benefit of the doubt, but that's the only reason *I* know for keeping just one fingernail long (and especially a pinky nail).

 

[Kirby]

Cool stuff. :thumbsup:

 

[Jeff7181]

Originally posted by: Vortex22

Originally posted by: CurseTheSky
He's not the greatest speaker in the world, but he does a good job explaining it. I've known how manual transmissions worked since I started working on cars, and I always assumed automatics were similar (just with some way of automatically selecting a gear). Man was I wrong.

The coke nail on one of his pinkies kept throwing me off though. =/

According to Wikipedia, Honda auto transmissions actually do work this way (similar to a manual), I didn't know that.

Only certain ones, like the ones that let you select the gear... or dual clutch transmissions.

Originally posted by: BlahBlahYouToo
so is the fact that the gears are always engaged in an auto the reason why it gets worse fuel economy than a standard?
the extra friction?

The reason for the power loss/fuel economy loss with a traditional automatic is partially due to the torque converter, but also the pump that's required to build the 70-120 psi fluid pressure needed to apply clutches and whatnot.

 

[Pacfanweb]

Originally posted by: BlahBlahYouToo
so is the fact that the gears are always engaged in an auto the reason why it gets worse fuel economy than a standard?
the extra friction?

Autos tend to weigh a lot more. It's a combination of reasons, really. Not as much difference in today's cars, though. Was a lot more back when autos were only 3 speeds.

 

[Jensenfc]

Originally posted by: CurseTheSky

Originally posted by: AdamK47
What's up with his pinky nail?

See my post above. I'm giving him the benefit of the doubt, but that's the only reason *I* know for keeping just one fingernail long (and especially a pinky nail).

In past videos he 'claims' that it is a 'redneck nose picker'

Beside that his videos are great to watch. Hours of fun and you don't feel so guilty because you are learning a lot in the process.

 

[BlahBlahYouToo]

damn, this guy knows a TON of shit, and not just car related.
must be a mechanic.

 

[alpineranger]

Originally posted by: Jeff7181

Only certain ones, like the ones that let you select the gear... or dual clutch transmissions.

No, hondamatics from the first ones do not use planetary gearsets in an effort to circumvent borg warners patents. Honda has no dual clutch transmissions.

 

[Raduque]

Originally posted by: alpineranger

Originally posted by: Jeff7181

Only certain ones, like the ones that let you select the gear... or dual clutch transmissions.

No, hondamatics from the first ones do not use planetary gearsets in an effort to circumvent borg warners patents. Honda has no dual clutch transmissions.

Yep, the transmissions from the 3rd generation Accord (and likely Civic and Prelude from the same years) use gears like a manual and lock the synchros using hydraulically operated shift forks instead of manually operated ones. IIRC, the shift mechanism relied on vacuum and the VSS/speedo cable to decide when to shift.

I heard a lot of these trans like to eat synchros.

 

[Tiamat]

neat stuff!

 

[Demon-Xanth]

I've seen some of his other videos. He's the kind of guy I could never see hosting a show, but can see working as a technical advisor/writer for one.

 

[lurk3r]

Originally posted by: Jensenfc

Originally posted by: CurseTheSky

Originally posted by: AdamK47
What's up with his pinky nail?

See my post above. I'm giving him the benefit of the doubt, but that's the only reason *I* know for keeping just one fingernail long (and especially a pinky nail).

In past videos he 'claims' that it is a 'redneck nose picker'

Beside that his videos are great to watch. Hours of fun and you don't feel so guilty because you are learning a lot in the process.

In Canada its more likely for picking seeds out than coke.

 

[geno]

Originally posted by: BlahBlahYouToo
so is the fact that the gears are always engaged in an auto the reason why it gets worse fuel economy than a standard?
the extra friction?

FYI the gears are always "engaged" in a manual transmission as well. As said before, the frictional losses through the torque converter are the main point of loss.

 

[TonyH]

A bit vague and inaccurate in some cases with that particular tranny but he does get the general idea across.

The shaft he kept referring to as a "pump shaft" is the shaft that drives the direct clutch drum which sits behind the planetary assembly. The pump is actually driven by the milled flats on the torque converter hub.

 

[geno]

Finally got around to watching this, it definitely clears up some questions I had in regards to auto transmissions

 

[Rubycon]

How did I know this was going to be DavidsFarm video? :laugh: