Roll After Putting Into Park

The Prius parking pawl is a very robust device. It is a helix gear-like device that screws into place. I don't think you will have much luck trying to break it. The play you describe is normal, and comes from the discrete positions allowed for locking.

Tom

 

I also noticed this! At first i thought it was some kind of defect...

 

Another unnerving thing about the parking pawl play comes when you sit with the Prius on but in Park. If you don't hold the brake or set the parking brake, when the engine starts your Prius will lurch forward a few inches. It's not a big deal, but it does scare some people.

Tom

 

The Prius rocks like nothing I've ever known when put into park. That said, I still don't bother with the parking brake, even on my inclined driveway

 

When you leave it in park without engaging the parking brake you are using the motor and transaxle mounts to hold the car in place. The lurch comes from the car taking up the flex built into these rubber pieces. My theory as to why the Prius has so much lurch after engaging park is because the Prius probably uses motor/transaxle mounts with a lot of flex in order to smooth out the transition between ICE and Hybrid motor.

That being said, I've never understood why people don't use the parking brake. I'm used to driving stick so I always use the parking brake.


Parking without using the parking brake (particularly on inclines) is a quick way to wear out your mounts and induce a bunch of slack/shunt into your driveline. Particularly if the mounts are designed to flex a lot to begine with.

 

Years of habit. I can't remember the last time I put a car in park without first setting the parking brake.

When my son was learning to drive, I remember giving him a hard time for setting the parking brake and not leaving the car in gear. This was a Honda Civic with a manual transmission.

Parking brake first, then make sure the car is in gear. With the Prius, that is easy because turning the car off automatically sets the parking brake.

I guess I'll never know the behavior associated with turning the car off and walking away with the parking brake not engaged.

 

Are you sure it automatically sets the brake? I'm sure it engages the parking pawl in the transaxle, but I don't think it actually sets the brake.

 

Um. Have you tried parking your prius on a steep hill before? Here's my experience when using the parking brake on a steep hill. Even with my foot on the brake, applying as much force as possible, as I release the parking brake, the car will lurch or roll. It is an unsettling feeling. The only way I have found, living on a steep hill, to remedy this is to have the wheel actually touching the curb, turned away or towards, depending on your parking position.

 

It automatically puts the car in park. Hitting the park button before powering off is redundant and in fact, some of us have a habit of skipping the park button when powering off. You can confirm this by watching the park button light up green when you power off.

But, no, it doesn't engage the foot/parking/emergency brake.

 

When powering off, the Prius automatically puts the car into park, but does *not* set the manual parking brake.

Now you have it verified.

Tom

 

I'm sorry, I'm going to dispute the claim the Prius rocks more than any other car. The anti-Prius (2001 Nissan Pathfinder LE AWD) moved twice as much as Pearl. To make it even scarier for new owners/those who worry too much, the AWD would disengage about 5 seconds -after- you stopped and put it in park with the engine running, and the vehicle would lurch, 2-3 inches if the parking brake was engaged, further if not (up to 5 inches). Now -THAT- scared people!

Of course, Toyota could reduce the play in the parking lock. But then you'd have trouble sometimes getting it to release. I like it the way it is.

 

Someone tried to claim this was a safety issue when the 2010 was first released.. I checked the relevant standard at that time. A vehicle is allowed to roll 6 inches in park (150mm, to be precise). Please use your parking brake.

I also live on a steep hill (with a 2009), and I think I can explain what saechaka describes. When you set the parking brake, as most of us know, it only locks the rear wheels. When the service brakes are released, this causes the vehicle to depress in the rear (maybe someone can explain the exact mechanics behind that.. I can't seem to wrap my head around it right now). When the parking brake is released, the rear raises back to a 'normal' level. However in my experience, the car does not actually move.. it's just shifting around on the suspension. Of course the 2009 and 2010 are different here, as the 2010 has discs in the rear. It doesn't seem like that would make a big difference, though.

(IMO, you don't want your tires touching the curb while parked.. certainly not in my neighborhood where there are old stone curbs with jagged edges)

 

The geometry of the rear suspension causes the wheels to move up and forward under compression as the torsion beam axle tilts forward. When you are parked uphill gravity wants to pull the car back down the hill. This forces the locked rear wheels to effectively push forward on the suspension, which moves in a prescribed arc slightly forward, but mostly up.

 

What you're feeling is the compliance in the suspension. The actual, proper way to park on an incline is to apply the brakes, place the car in neutral, apply the parking brake, carefully release the brakes, then place the car in park. This method takes any strain off of the driveline.

This is not that big of a deal parking on a hill. However, when taken to extremes this is an important step. When offroad on a very STEEP hill, failing to do this can place enough torque on the driveline that you cannot get the truck out of park without exerting A LOT of force.

 

That's just due to your superhuman strength. Don't worry. It probably has a salutary regenerative effect on the battery.

 

I do live on a steep hill and did not realize there was a procedure to using parking brakes on a steep hill. I just parked, turned off the car, then applied the parking brakes last. I'll give your suggestion a try.

 

Absolutely, the correct thing to do is bring car to a stop with footbrake, and keep firm (but not crazy) pressure, apply the parking brake, then set P or turn off the car.

When pulling away, foot on footbrake with firm pressure, release parking brake, then engage D, then release footbrake. you'll never roll again