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Discussion Starter · #1 ·
Hey, I LURRRRRRRVE my xB, but what's up with the Auto Tranny Roll Back?? Even on a ridiculously slight incline near my home, if I brake for the STOP sign (generally a good practice), car starts to roll back if I'm holding more than 5 secs!

Now, it doesn't ALWAYS happen, but why should it EVER? No other automatic car I've ever owned has done that. The dealer says, "Oh, that's normal" and I've seen a few other people with same prob on other forums, but the real question is, how do you stop it? Ideas?
 

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Er, not to be a nitpicker or anything, but you really should NOT take your foot off the brake at a stop sign or light if you aren't going to be going right away...
If someone were to bump you from behind, they'd push you into the middle of a crossroad.

That being said, IMO, the car should NOT roll back, the transmission should hold. I wonder if they all do this?
Anyone else want to chime in? Mine is manual, so I wouldn't know. I have to brake :)
 

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Hah, when mine did it the first time, I was wondering why and really did not pay any attention after that although I only had my XB for 4 months. So everytime I just make sure I step on my brake tight when I am on the hill. I drove manual for a long time before so I know what it was like stopping on the hill. And I am totally agree that automatic probably should not roll back.

I am interested to see what other members have to say about this.

Thanks!!!
 

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Discussion Starter · #4 ·
Oh, well, I guess I was a little unclear---I never take my foot off the brake on an incline, it's in those 2 secs when I do shift to the gas that the rollback begins....

HERE'S WHAT I'VE LEARNED about this on tech forums and just surfing around:

1) Lots of small-engine cars with auto trans do this, particularly Toyota Matrix, older Rav4s, and even the Highlander, as well as some smaller Ford models.

2) It is apparently not a defect. The auto trans bases it's control on fluid pressure, which is low when idling, so the trans doesn't hold the car (on an even surface it doesn't matter, but on an incline, gravity rolls you). There were other explanations offered but this one I at least could understand.

3) The Nissan GTR is a small car with an anti-rollback feature. Not that I'd give up Scion for that!

That's it--let's see if anyone comes up with something more definitive...
 

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I made a point to pay attention this morning pulling out of my garage... no rollback on the driveway. In fact, in drive, I pulled forward. I'll have to look for more of an incline. A manual Subaru I had 10 or 15 yrs ago had a hill holder feature, but I don't think it worked. If that car could do it, I'm surprised it's not a standard feature on all cars now.
 

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Auto transmissions "slip" when stopped by bypassing fluid in the torque converter. More engine RPMs cause the internal fluid friction to increas and the car moves. It's a fluid dynamics thing.

Any car can roll back if the engine rpms are not sufficient to reach the threshold of friction in the converter. There is nothing mechanical in the transmission that stops it.
 

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just pull the parking brake before you shift into park and before you let go of the brake. it's become habit for me, and the car doesn't roll at all
 

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i drive manual, but i did notice it in my dad's Dodge Ram(van) his did the same thing.
 
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