All you AT folks....

[rhodesman]

When you park, do oyu put the car into "P" and turn off the engine or "N", power off, then "P"?

I started to park in the latter way: N > power off > P > take out key. Maybe I'm crazy but I feel it helps keep the torque out of the transmission and the car no longer "lurches" forward when you take your foot off the brake. I also engage the E-brake regardless but I grew up on a manual and it's more of a habit than a thought at this point.

I'm just curious if others do this and if there really is any benefit to it. I figured leaving that kind of load on the transmission/drive train was not ideal but I don't have any real facts to back that up.

Thoughts?

[PopsnBurbles]

When I had a torque converter automatic, I always used to engage P -> turn off -> pull up handbrake/e-brake -> left foot off brake = no lurching. Well, I do the same thing with DCT automatic. As far as lurching goes, that's the way I deal with it. AFAIK, I do not really think that N and P have a significant difference in terms of "holding" torque.

[tock172]

I've owned many automatic BMWs and I don't think there is any need to power down the engine before inserting the transmission selector into park. On most automatics, Park and Neutral are actually the same position, but with Park, a pawl is engaged to keep the car stationary.

In my opinion, the best way to operate the transmission is to kill the engine, put it in park, keep your foot on the brake pedal, engage the parking brake and then release your foot from the pedal. This puts the pressure on the parking brake as opposed to the transmission Pawl.

[KNS]

Originally Posted by tock172

In my opinion, the best way to operate the transmission is to kill the engine, put it in park, keep your foot on the brake pedal, engage the parking brake and then release your foot from the pedal. This puts the pressure on the parking brake as opposed to the transmission Pawl.

I try to get my wife and daughter to a variation of this with their cars but they just won't. Putting an automatic trans in Park first (without keeping your foot on the brake pedal and pulling the hand brake) particularly on a hill puts a lot of undue strain on the transmission pawl. Doing this on a steep hill has the whole weight of the car being held by the transmission pawl.

I pull the hand brake first, then take my foot off the brake pedal and then put it in to Park.
I guess driving manual trans cars my whole life I'm just used to using the hand brake first.

[Top Gon]

I put it in neutral for a second and let off the brake then brake again and engage park then handbrake. This whole process happens very quickly though.

[chunho01]

How about putting my leg on brake all the time.

Never release it until everything has been done.

[e36addict]

Not auto, but my driveway is a bit of a hill, and I always go N > handbrake > let off brake pedal > park. It bugs the hell out of me for the car to be resting on the parking pawl. And that terrible noise it makes when you try to get it out of park... Uggghhh

[rhodesman]

Originally Posted by e36addict

Not auto, but my driveway is a bit of a hill, and I always go N > handbrake > let off brake pedal > park. It bugs the hell out of me for the car to be resting on the parking pawl. And that terrible noise it makes when you try to get it out of park... Uggghhh

THIS! I actually convinced my wife that was bad enough and I got her doing the E-brake on her car where before she never used it. (It's the one thing I've contributed to our relationship LOL!)

[rhodesman]

Originally Posted by tock172

I've owned many automatic BMWs and I don't think there is any need to power down the engine before inserting the transmission selector into park. On most automatics, Park and Neutral are actually the same position, but with Park, a pawl is engaged to keep the car stationary.

Would it be fair to say that the torque converter keeps some torque in itself if you go P > Power off > foot off brake?

I ask because in my garage (level surface) if I do that, the car will lurch forward if I don't engage the e-brake first. This is why I did the N > power off > E-brake > P > foot off brake. This stopped that lurch forward from happening. This is why I thought the transmission was holding some of the power inside it.

[MotoWPK]

Originally Posted by rhodesman

Would it be fair to say that the torque converter keeps some torque in itself if you go P > Power off > foot off brake?

I ask because in my garage (level surface) if I do that, the car will lurch forward if I don't engage the e-brake first. This is why I did the N > power off > E-brake > P > foot off brake. This stopped that lurch forward from happening. This is why I thought the transmission was holding some of the power inside it.

As stated previously, both P and N put the transmission in neutral. The torque converter doesn't 'keep torque in itself', it is transmitting torque as long as the engine is running (actually as long as there is a speed differential across the converter, but for the sake of this discussion, when the car is stationary, we can simplify that to as long as the engine running).

With the transmission in neutral, P or N, all internal clutches are disengaged, but, there is always some residual drag across the disengaged clutch, particularly with wet clutches as is the case here. This clutch drag results in some, small amount of torque being imposed on the drive train which is why you experience the car lurching forward when you release the foot brake. If the parking pawl is engaged when this occurs, then you can expect some load to be imposed on the pawl, however, it is quite small, certainly far less, for example, than would occur with the pawl holding the car against a steep incline.

If you apply the handbrake, with sufficient force, prior to releasing the foot brake, then the handbrake will hold this residual torque and prevent loading of the parking pawl. Again though, this load on the pawl is quite small and I would not be concerned about it. That said, I do agree that best practice is to have the habit of applying the parking brake prior to releasing the foot brake so you are consistently doing this and having the parking brake take the load when you are parked on an inclined surface.

[rhodesman]

Originally Posted by MotoWPK

...

THANK YOU!!! I think you answered my question perfectly and put all my concerns to bed (as well as everyone else)!

I can rest easy now!