I noticed (not the first time i noticed though) that my car can just sit still when stopped on a hill (going up). I can take my foot off the brake, and it stays still. It’s an automatic. I was just wondering if anyone knows exactly how that works…
while im on the subject of my car…has anyone ever experienced this problem: My transmission is shown on my dash. theres a little red square that lights up around the P when im in park. sometimes this little red light doenst light up, in which case im in some kind of suspended animation state: im not in park, b/c i can’t subsequently shift back into drive or neutral or get my ket out of the ignition. it only happens when its cold out though. many a time i have taken a short little trip out on a cold day and have been forced to sit in my car until the little red light goes on around the P on the dash, so i could get my key out of the ignition. can anyone tell me whats wrong with my car??
“I am so smart, I am so smart, s-m-r-t, i mean s-m-a-r-t”
I can answer the first part of your post, at least. Your automatic transmission is connected to the engine through a fluid coupling, rather than a mechanical gear train. The fluid coupling allows a certain amount of slippage.
When you stop at a stop light the engine is still turning but the drive train is stopped. If there were a mechanical connection between the two the engine would stall. That’s why you have to depress the clutch pedal when you stop a car with a standard transmission.
With the automatic transmission the fluid coupling just slips. However, it still generates a little force – and this is what keeps you from rolling backward on a slight upgrade when you take your foot off the brake. The same force lets your car creep forward on level ground if you take your foot off the brake. Fortunately your brakes can keep the car from moving against this slight force or you would have to shift into neutral every time you wanted to stop.
Just a guess as to the second part of your post, but my wife’s car (a Honda Civic) sometimes has a similar problem. It took me a while to figure it out but in her case it wasn’t related to cold at all, but to how vigorously she shifted into park. She would put it in park, but in a very gentle, lady-like way. The lever would move to the correct position but some switch somewhere wasn’t making contact so she would end up in the “park/not park” limbo you describe.
This never happened to me because I would always slam the gear shift around in a manly manner. It took her a while to convince me it wasn’t her imagination.
It’s possible the same thing is happening to you. The problem may be exacerbated by cold weather by making the switch a little stiff, so it is even less responsive than normal. Try pushing it into park harder than usual and see if that doesn’t clear it up.
The transmission has a set of safety interlocks that, among other things, prevents you from removing the key when the car is in gear (their primary purposes, however, to keep you from shifting into gear without your foot on the brake, or from starting the car while in gear). It would appear that this interlock is not fully engaging.
I agree with pluto: put your foot on the brake, move the lever out of Park and back in again with a tad more authority (or, if you wish, in a more ‘manly’ manner).
He’s the sort to stand on a hilltop in a thunderstorm wearing wet copper armor, shouting ‘All Gods are Bastards!’
I cannot tell you the why of your parking problem, but I can offer some suggestions as to how to quickly fix the problem each time it happens. The same thing happens to me on occasion, and I have found that one of two things always helps.
Remove your foot from the break, and reapply your foot to the break. Then try to shift. (common)
Question 1) I think Pluto answered this one about as well as anyone could, but he left out: Don’t do it. It (probably) won’t cause any immediate damage, but it will significantly reduce the overall life of your transmission.
Question 2) Could have a lot of different causes depending on make/model. In my experience, the most common is low trans fluid, or a dirty filter. (worse when cold because fluid is thicker then)
phm, why does it hurt the transmission? It seems to me it’s exactly the same as stopping at a red light with the transmission in Drive and a foot on the brake. Or is that bad as well, if done for more than a few minutes?
The thing is you’re not using the brake to hold your car stopped, you’re using the transmission. Or the friction in the fluid coupling. It wears the transmission more to use the transmission to hold you stopped. Use the brake. That’s one of it’s purposes.
With the car in drive and the engine idling, the engine is continually causing the fluid in the torque converter to exert a small pressure against the transmission and drive line. This pressure is the same whether the car is stationary due to your applying the brakes or due the the force of gravity upon the vechicle on an incline. Therefore, it does not matter whether you let the car sit on the incline with or without brakes on, as long as it does not move for you.
others:
Putting the tranny in Park to stop at red light doesn’t strain the coupling. There’s a mechanical lock that immobilizes the drive train. However…
A) the act of shifting into and out of gear at every light would certainly cause wear, and;
2) some transmissions don’t cool their fluid as well when not in gear, so long idles in Neutral or Park could overheat things.
Sure, I’m all for moderation – as long as it’s not excessive.