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Old 03-07-2008, 08:43 AM   #1 (permalink)
apgrok1
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Accidental Transmission discovery (bump started my automatic)

Lately, I have been throwing the Auto trans in my car in Neutral when approaching a stop light, and if I know it will be a long one, I shut the engine off. Typical hypermiler stuff. I usually will turn the key off for 5 seconds and then turn it right back on. Anything less than 3-5 seconds means the engine has a chance of refiring.
Here's the incredible part, last night I was talking on my cell phone to my wife while driving. As I came up to a light I knew was going to be a long one, I shut the engine off. When I turned the key on five seconds later, the car re-started! I had shut it off in drive and the automatic trans had kept the engine turning! I didn't think that was possible, but I had just bump started my car with a slush box!
On the remainder of the trip home, I performed my discovery again and again and ran through a few other scenarios. It will easily restart after long periods (10-15 seconds) as long as I am above 30 mph. It seems to want to downshift at that point. It seems that the trans will keep turning the Stator as long as the TC housing turns fast enough to keep pressure on the clutch packs. It will also not bumpstart if the engine was shut off in neutral and then put into drive after the engine is off.
It doesn't coast as far (naturally). I have a 2000 Cirrus with a 2.4L and a 41TE (A604) trans.
I am not recomending anyone try this as I have no idea if this damages the trans or not. You should also not do this if you are close behind someone.

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