For all of ya with auto's, ever had the car start rolling backwards on you even in drive gear? I was on a slight incline the other day and that happened...should I be concerned?

 

Can you tell us how much your car have rolled back?? One feet, Two feet, couple inches?

 

it rolls back on me too on an incline. my friend, whom i carpool with, lives on a very steep incline and i'm always rolling back. don't know how much b/c i step on the brake... i'm guessing that it would eventually stop - but not at 2 ft, maybe a foot. this happens in my coupe and bmw.

 

Well maybe a few inches, but I put on the brakes before it goes further. Funny, never happened on my bimmer...it would just sit in equilibrium!

 

heh, the slope is like 40 degrees even worse, the driveway goes to a road that is at like a 30 degree angle! winter/snow is not going to be fun.

it doesn't always happen so i'm guessing the anti-rollback device is a relatively variable system - that is, sometimes its close to the point where it catches, sometimes its a little further. i'm totally guessing w/ the distance b/c i always brake. and this has happened to pretty much every auto i've ever owned (soobie, acura, and others)

 

"Anti-rollback device"? I think it's related to the idle speed -- that's what holds your automatic-transmission car on a slight grade. If the normal "resting" idle is somewhat low (which may be the correct setting), then it won't hold on much of a hill -- this is perfectly normal. You're supposed to apply the brakes when you're stopped .

 

i could've sworn that there was something about the gears that would prevent an automatic car from rolling back. but i'm not a car expert so i'm probably wrong.


heh, i thought this was funny - from cartalk.com about manuals:

Dear Tom and Ray:

When I was young, my Dad and I each owned Studebaker autos. My last one was a 1949. All of them were standard transmission cars and all of them had as standard equipment a hill-holder. This rather nice device holds a car in place while waiting for a light to change at a hilly intersection. You merely keep the clutch pedal at the floor, step on the brake pedal, and then you can remove your right foot and put it on the accelerator. Then, as you release the clutch pedal, the brake is released, too. And by then, you're going forward, so the car doesn't roll backwards into the car behind it. Whatever happened to hill holders? Does anybody still make one? Don

Ray: Subaru still makes cars with hill holders, Don. And as far as I know, they're the only ones who still do. I guess there's just not a public clamoring for them. Most people must still want the "challenge" of seeing if they can get moving before rolling backwards into the car behind them.

Tom: I actually have my own modern version of the hill-holder, Don. I check my rear view mirror, and when the driver behind me looks away for a minute, I ease back until I'm resting against his front bumper. So HE'S my hill holder. It works great.

 

MarkL, i think you're right (for once ). here's another article from cartalk that helps explain it. basically, the power of the engine keeps the car from rolling back but if the incline is high enough, it will roll back and braking is recommended.

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Dear Tom and Ray:


I had a problem with a run-away car. I had a 1977 Delta 88 Royale with 35,000 miles on it. I was driving up a slight hill, and stopped at a stop sign near the top. The car evidentally stalled out and I didn't realize it. I had depressed the gas pedal with the intention of making a left turn. But instead of going forward, the car drifted backwards and turned into the corner of a house. I had shut the engine off thinking the car would stop, but it didn't, and the brakes and steering didn't seem to work. I panicked and didn't know what to do. Now I won't drive again. What do you think could have happened that it went out of control and drifted backwards? Dottie

Tom: Nothing happened, Dottie. The car just stalled. And you're right; you panicked.

Ray: When a car stalls on a hill, it will start to roll. And without the power of the engine, the power steering and power brakes disappear...as you found out. The brakes and steering still work, but it's very difficult to stop or steer the car, especially if the car is large and heavy, and you happen to be small and light.

Tom: And turning off the ignition will not make the car stop. All that does is make the ENGINE stop. And in your case, the engine had already stopped! Plus, turning off the ignition can lock the steering wheel, which really does make it impossible to steer.

Ray: So what should you have done? First of all, leave the key where it is. That will at least keep the steering wheel from locking up. Next, try pushing on the brakes with both feet. It takes a lot of pressure to stop a big car without power brakes, but most people can do it.

Tom: If you don't think you can stop the car by standing on the brake pedal, you have two more options on a car with an automatic transmission. First, you can use the parking brake. While it's not always effective (which is why they don't call it the "emergency brake" anymore), if you're rolling towards a house, it's certainly worth a shot. And if the brakes are in good shape, the parking brake will generally stop a slow moving vehicle.

Ray: If that doesn't work, then you should just slam the transmission into Park. You may hear the transmission grind or clack when you do that, but isn't that better than explaining to to Mrs. Miller why you thought the dinner party she invited you to was a "drive through?"

 

Living in hilly San Francisco and driving automatics for decades, I've never given this subject much thought. Every car I've driven (domestic and Japanese to this point) has had the tendency to roll back on severe inclines.

By habit, I use the brakes to prevent rollback. Way back when, someone told me that holding a car in place on a steep hill using the accelerator is bad for the transmission. True?

 

Young - there is something when you place the auto trans in "park". It's called the parking "pawl". It's a mechanical device (I believe) that moves into position to lock the trans. An auto trans car will drift slightly depending on the position of this pawl when engaged, maybe 1/2 inch or so, before it locks.

Geistmeister - I believe it's bad to hold an auto car on a hill by using the accelerator because by raising the idle, you are causing the torque converter to heat up higher than normal idle temperatures and can therefore cause damage in the long run.