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Old 10-03-2010, 01:03 PM   #6 (permalink)
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Pasta - '96 Volkswagen Passat TDi
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Quote:
Originally Posted by Sularus View Post
actually it could harm the transmission. The transmission needs constant fluid to maintain temperature and lubrication. If the engine is not spinning the torque converter and then the pump, there is no fresh fluid being pumped through the tranny. Over time, this could result in the tranny being overtemped in certain areas, reducing the life of clutch packs and other parts.

It is advisable to either coast in nuetral or coast in gear. Do not shut the engine off while coasting in an automatic transmission car.
You understand, of course, that some automatic transmissions are actually designed to use in neutral with the engine off?

Several of them also have a "recommended" towing distance that the vehicle can be used in neutral without the engine running before damage becomes an issue.

Most people aren't going to coast for miles in or out of gear with the engine off, and the chances of the transmission overheating in the few hundred feet (up to a mile) that the average driver would coast is almost nil. I've been EOC with automatic transmissions for awhile now, and have yet to damage one, including the Dodge Caravan in which you can actually set the TCM to display clutch wear and recalibrate the transmission controller based on clutch pack use.

Frequent clutch displays showed no abnormal wear from EOC in that particular vehicle, which isn't rated for flat towing by the MFR.
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