Park gear

Sorry, I sure don't. I too am assuming that it mimics the function of the Park gear in a regular automatic transmission. But that is pure speculation. There are people on this board who are infinitely more knowlegable than I am about these matters, and hopefully one of the can answer.

As an aside, I'm finally picking up my Prius tomorrow. I doubt I'll be able to sleep tonight out of anticipation.

 

Hey, congrats on getting the Prius, you need to print off the delivery checklist that is on this site and use it.

Mid-week I was at the Toyota dealer's parts counter and that set of repair manuals for the Prius is avaliable through the 800 number cited in the back of the Prius owners manual. I keep thinking that this is a worthwhile investment, even though it is likely to rival a college textbook in cost.

I can tell you that I have experienced a little confusion of expecting the car to move after taking off the parking brake and not shifting it, and then I feel some loading going on like a catchpaw of a typical automatic transmission. (yeah, I was distracted by passengers, cell phone, etc. those two occasions)

Now, if a regular automatic transmission gets that catchpaw "loaded up" by holding a vehicle on steep grade or being hit by another vehicle and pushed, it puts a load on that catchpaw that is VERY hard to get out of park by moving the transmission lever.

If that ever happens in a regular vehicle, DO NOT attempt to force the transmission out of park. Get another vehicle to push you uphill, or the direction you pushed from to "unload" the catchpaw.

Personal experience? Yes, I went to a football game, parked on the steep grade of a side street, failed to set the parking brake as hard as I could and it loaded the catch paw. I forced it out of park and destroyed that transmission in short order. Obviously I smashed some metal off in that yank out of park and I WILL NEVER DO THAT AGAIN.

So, the moral of my sad expensive tale is that:

1. Treat that gear with tender loving care
2. Make a special point of setting that parking brake as good as you can on a grade. DO NOT let off the brake until you set that parking brake as hard as you can on steep grade.
3. In a Prius, their is some setup to let the mechanical catchpaw out, but it still can get the load put on it, if it acts squirrely then get another vehicle to "unload" it.

I'm not the genius, I am the guy that blew the expensive transmission. Experience is the most expensive teacher, so learn from others is cheaper.

 

Nah, I have Prius for only 3000 miles, and most of what I know about the vehicle comes from others here. I'm no expert by any stretch of imagination.

My driveway is uphill, and when I press P and let go the brake pedal, something "clicks" and the vehicle backward movement stops. Just like my old '91 Camry did.

 

It's a normal physical parking pawl. IE, it's a wedge that goes into a gear somewhere in the drive train to keep it from rotating.

It's electro-mechanical instead of purely mechanical, I'm assuming a servo of some kind.

Only place I've seen it mentioned by Toyota is in the Emergency Response Guide

http://techinfo.toyota.com/public/main/2ndprius.pdf

I'd bet it's not in the PSD. Remember, there are gears between the drive shaft and the wheels outside the Motor/PSD/ICE assembly and it seems logical that it's in there. But, it could be in the side of the PSD too.

 

Yes.. to answer your original quest from the font of all Prius knowledge,(Canuck)... all of the above posts which correctly answer your question would have been my reply. Sorry to have been absent from being available to answer this most important question but I slipped on the ice the other day and have been busy getting stitches and a cast on my hand. I am happy to report that our humble 2005 Prius pulled herself through the most mountainous snow (3-4 feet) banks during the emergency where I was safely placed in the hands our British Columbia Health system and spent a only 6 hours to get an X-ray and a cast without spending a dime except for the $1000/year taxes.

 

Hmmm, I sense a certain, how shall I put it ... hostility??

My Dad is American and my Mom is Canadian. Half their working lives in the U.S., half in Canada. They can't move back to the U.S.

Well, they can any time they want to. They'd just kiss away their OAS, CPP, etc etc. They would love to move to a climate where it stays nice year round, like southern Utah. You can bet I'd ditch this place in a heartbeat!

If anything serious happens, I drive them into Minnesota or ND. My Mom once spent 12 hours waiting for an x-ray after she slipped on some ice. Yeah, let's not forget all those high taxes they paid while working.

 

Sorry about the delay jeepien, just got back from an aborted attempt to drive out to the hobby farm. Had another nasty blizzard and they just closed the Trans Canada. Almost got stranded in BFE too.

Thank God for winter tires. It's very bad out there.

I have the shop manuals on order. Until they arrive, I can only guess the Park button uses a solenoid to engage a pawl to lock the transaxle.

Some have expressed concern about parking on steep hills without using the parking brake. This concern is valid, especially if the car is facing backward down the hill. I doubt the solenoid would be able to disengage the pawl. Usually you need a push to relieve the pressure on the pawl.

As Robert Taylor mentioned, you can cause $$$ damage if not careful. Especially on a modern electronically controlled transaxle with nothing "extra."

Most older automatic transmissions (Ford C6, Chrysler 727, Chevy TH400, etc) were very stout units. Very inefficient, but very stout. The parking pawl was a large metal finger that latched onto the splined output shaft. You really had to try hard to bugger that up.

I think it's a very good habit to set the parking brake before pressing Park. This way you don't have to worry about the parking pawl. About the only time I wouldn't recommend using the parking brake is if it could freeze.

I speak from experience: that is NO fun.

 

Canuck: when my Mom fell on the ice she broke two fingers in her left hand. It needed stitchs and she got an infection. Make sure you follow up with a tetanus/diptheria shot ASAP, unless you've had a booster shot within the last 5 years.

 

It appears Tempus has answered your question best, before I could. Therefore, I shall save my intellect for other questions, like why wheels are round. :lol:

 

Well I'm flattered you think I might know, but I am no engineer. I do share the curiosity, as it doesn't seem like much of anything happens when the button is pressed (no clunk, squeech, etc).

On vfaq.net, a compilation from a 2-G yahoo group, this is what it says about the 2004 model:
"When I park, do I have to push the "Park" button and turn off the headlights?
No. To park, after you have stopped you can just push the "Power" button if you want, without pushing "Park" first.  Pushing "Power" will put the car into Park, and it will turn the car off.  When you open your door, the headlights will turn off.  So if you want, you can leave your headlights switch in the "on" position at all times.  This will mean your headlights are always on when driving, such as with Daytime Running Lights.  And you won’t have to remember to turn on the headlights when it gets dark.  (Note, however, that leaving the switch on drains a bit more battery power than leaving it off, so don't leave the  switch on if you will not be powering the car up for some time)."

from machinedesign.com review of 2004 Prius:
"I find the separate "Park" button quirky but it's necessary should you want to keep the car "on" but not in motion."

There are many reference to the "transaxle" being in the "P" position and limitations on other operations if this is not the case. So it seems to be an electrical in addition to a mechanical function. Not sure though.

I did find the Toyota techinfo pages but they require a subscription. Owner's manual is rather hazy on a lot of things.

Happy weekend!

 

8) Tempus,

This is what I found reading your link:

Electronic Gearshift Selector
The Prius electronic gearshift selector is a newly developed momentary select shift-by-wire system that engages the transaxle in Reverse, Neutral, Drive, or engine Brake modes.
• These modes may only be engaged while the vehicle is on and operational (READY -on), except for Neutral which may also be engaged while in the ignition-on mode. After selecting the gear position R, N, D, or B the transaxle remains in that position, identified on the instrument cluster, but the shift selector returns to a default position.
• Unlike a conventional vehicle, the electronic shift selector does not contain a park position. Instead, a separate P switch located above the shift selector engages the park position.
• When the vehicle is stopped, regardless of shift selector position, the electro-mechanical parking pawl is engaged to lock the transaxle into park by either depressing the P switch or pushing the power button to shut off the vehicle.
• Being electronic, the gearshift selector and the park systems depend on the low voltage 12-Volt auxiliary battery for power. If the 12-Volt auxiliary battery is discharged or disconnected, the vehicle cannot be started and cannot be shifted out of park.


Ben

 

Hello jeepien,

There is a "Parking Lock Actuator" attached to the final gear box. So, this is another "by wire" technology.

I do have a "Toyota Electronic Technical Manual" CD-ROM for 04 Prius. It is very worth to read it if you understand Japanese.

Regards,
Ken@Japan

 

It appears from the original post I am to chime in here. Everything I know I learned here or John's site or PriusOnline. But I can state with some authority that if you hit the Park button with the car backing up and not quite stopped that you will come to a sudden and compleat stop. That seems to confirm that a lock is placed in the gear. This only happened once and will not happen again. I can not speak to forward motion, someone else can do the experiment. Clearly this sudden stop will not happen if you are moving at any speed at all. I was moving at less than a walk when this happened. Others have chronicled hitting the P button at speed. Nothing happens. FWIW

 

What a great way to get many responses! I agree with the above.

The original poster used a bit of code by enclosing the word you in [ ] brackets, it substitutes the screen name of the VIEWER, thereby inviting us all to reply by name.

Of course I had the right answer too...

 

Bob Allen here: Glad you asked that. This question comes up all the time. As near as I can tell, the Park function reverses the polarity on the master battery and turns the motor into a giant gravity magnet which holds the car in place. Toyota is considering licensing this technology to NASA to help curb the nausa caused by weightlessness. What surprises me is that there is no warning on the owners manual about activating the P function if someone is standing right in front of the car. There have been several reports of the P function sucking grocery carts into the sides of Prii; the drivers obviously unable to make the connection between the P function induced gravity magnet and the grocery cart.
Someone asked that if this were true, why don't adjoining Prii repel each other once they are both in P functionality? Another good question, for which I have no answer. Prii are so hard to come by, and not cheap at that, that it's pretty rare to have two of them parked side by side. Dealers never have more than one, and if they do, you'll notice they are not parked next to each other.
Hope this helps.
Bob
p.s. why did you ask me??