Automatic Transmission FAQ

[CozmoNz]

After seeing the postin the General Questions, I decided to do a Faq on it.

Generally toyota automatic transmissions are 4 speed, 3 + OD (1, 2 and D), however, the new ones will probbaly be 5 sp .

The Buttons:

Little Red one with Japanese Writing
This is used to move the gear selector leaver when the car is not running. Such as towing it (by another car etc), not advised however, this can damage your transmission. And second of all, used to put into neutral, to roll it foward and such, mechanics use it... (getting it on a hoist the right way etc).

So generally, this button wont be used by jo blogs. So basically, dont touch it.

Power
This will hold you in the same gear for longer (say in a 4age, revving to 7,800 and changing at full throttle rather than 7,200). Giving slightly more power, and the more sporty feel about it. It also changes down gears at higher rpm to *keep revs up*?

Manual
Lock it in a gear, if your traveling up a hill, and it keeps changing from D (third gear) down to second, and back again, over and over again, hit this button when its in the low gear (or even better, bump it down to 2). This will lock it into that gear, and stop the problems .

Overdrive (OD)
Overdrive is well.... complicated to describe in mechanical terms... Think of it as a *rpm slow down* sort of item. You dont really need to know how it works, just why it does.

Pressing Overdrive, will turn it on (obviously lol), this will, in turn, be turned on automaticaly at around 60? (or is it 80?) kph, lowering your rpm, saving fuel, whatever. Thing is, around town, if your doing 60, and it kicks in to OD, youll discover youll be at around 1,200 rpm, or something low and pretty annoying.

Putting your foot down will get about 3 gear changes down..... Od off... down to second... down to first... THEN you roar off down the road.

Keeping OD off will prevent this, and may make it alot easier to drive around with.

On the motorway / 100kph zone, its a different story, if you cruise along the motorway at 100kph with OD off, youll discover the car revving to say 3,500+. Turning OD on will lower this, but of course, the same old problem, it will be less responsive, and passing will require another gear change down.

Keeping it on or off is really up to you. I suggest, if you dont know Jack and forget about it, Leave it on all the time, at least when you do go on the motorway, it will turn on for you, and everything will be hunky dory.

If youd rather control it yourself, by all means. so its really up to the driver.

questions? Feel free to correct me if im COMPLETELY wrong .

[pc]

Is overdrive really an overdrive or is it 4th gear?
A proper overdrive will make every gear higher geared. A 4th gear will be... what happens after 3rd...

What I want to know is if an Auto box is overfilled, will that affect gear changes. One night my auto wouldn't go into reverse, it was like it stayed in neutral. Went for a drive and it came right. I have noticed that the fluid level is filled up to the hot level, when the whole car is dead cold. Should I drain some out?

[CozmoNz]

Is overdrive really an overdrive or is it 4th gear?
A proper overdrive will make every gear higher geared. A 4th gear will be... what happens after 3rd...

What I want to know is if an Auto box is overfilled, will that affect gear changes. One night my auto wouldn't go into reverse, it was like it stayed in neutral. Went for a drive and it came right. I have noticed that the fluid level is filled up to the hot level, when the whole car is dead cold. Should I drain some out?

level should not be below L or above F. Simple

anything else can cause things that arnt ment to happen.

I just find it easier to describe overdrive as another gear, try explain the way stated below, to an old woman, or even your mum, on how overdrive works. its much easier saying *its 4th gear*. etc.

BUTTTT since its toyspeed, lets just quote someone else so everyone can understand.

If you want the big fat book explination, i can get that too if ya want....

Overdrive:

By definition, an overdrive has a faster output speed than input speed. It's a speed increase -- the opposite of a reduction. In this transmission, engaging the overdrive accomplishes two things at once. If you read How Torque Converters Work, you learned about lockup torque converters. In order to improve efficiency, some cars have a mechanism that locks up the torque converter so that the output of the engine goes straight to the transmission.

In this transmission, when overdrive is engaged, a shaft that is attached to the housing of the torque converter (which is bolted to the flywheel of the engine) is connected by clutch to the planet carrier. The small sun gear freewheels, and the larger sun gear is held by the overdrive band. Nothing is connected to the turbine; the only input comes from the converter housing. Let's go back to our chart again, this time with the planet carrier for input, the sun gear fixed and the ring gear for output.

Ratio = 1 / (1 + S/R) = 1 / ( 1 + 36/72) = 0.67:1

So the output spins once for every two-thirds of a rotation of the engine. If the engine is turning at 2000 rotations per minute (RPM), the output speed is 3000 RPM. This allows cars to drive at freeway speed while the engine speed stays nice and slow.

Isnt that easy to understand? now, do you want the complicated way of it too?

[spencer]

do we really need this its just basic stuff

[Dr-X]

Yes, ke70, because it's basic stuff that's being asked an awful lot lately. I think it should be put in the FAQ section.

Good work, Coz.

[ThoughT ExperimenTs]

do we really need this its just basic stuff

Yea it's great to have it all togeather with one thing, and if you are new to auto and yoru car came with no manual then it is very helpful

[CozmoNz]

Ive pmed wildcard... hopefully it gets dropped into the faq section soon.

[Lloyd]

Another note to add to that is that on the majority of cars the auto trans should be checked with the vehicle running and usually in Park. And if you've just drained and refilled the trans then put it in each gear for a few seconds before deciding that its been filled to the correct level just to make sure there is fluid everywhere.

Also, bumping it down to 2 will mean that that is the highest gear that the trans will usually switch to, it will still use first if it needs to. And on Tiptronic if you're using the manual shifts and over rev it will just chance itself anyway, not sure what normal autos do if they're locked down one and you over rev them

[ee904age]

. And on Tiptronic if you're using the manual shifts and over rev it will just chance itself anyway, not sure what normal autos do if they're locked down one and you over rev them

So true, tiptronics wont let you change down if you are over a certain RPM, so there not really a clutchless manual as some manufacturers advertise them.

All the normal autos Ive owned will go to the rev limit if held in a gear, they wont change, although some very modern ones might.

[thaphatty]

yep rev limit.