Re: Overdrive Engagement Speed Adjustment
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Just popping in
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Regarding the OD enable speed, I will add these thoughts...
The bigger the engine (greater low-end torque), the less that OD enable speed matters. To the Six, it's a big deal if you shift from second to third at 22 mph, and get 3rd OD instead of the 3rd direct that you had in mind. The big eight could care less - plenty of torque to muscle through. But, I believe that as time went on, the industry settled on a higher enable speed. (just based on a couple of data points from the fifties and sixties) If you wanted 2nd OD, you had to "wind it up" a bit. Otherwise, the shift progression was 1, 2, 3, 3OD. A much better scenario for the Six. I can personally endorse the analytical approach taken in this project, since a minor disagreement ended up costing me a beer. The car does drive beautifully!! Jeff P.S. You may want to tighten your security a bit, since you just let a Buick guy on the forum!!
Posted on: 2010/8/24 10:10
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Re: Overdrive Engagement Speed Adjustment
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Home away from home
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Pat, was your car going into 3rd OD by itself while you were shifting from 2nd? That's not right. You should probably take my car for a drive again. Even when my car is going fast enough where it is ready to shift into OD (signaled by the red light on the dash), it will not shift into OD during gear changes unless I take an unusually long time to make the shift.
Posted on: 2010/8/24 12:00
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West Peterson
1940 Packard 1808 w/Factory Air 1947 Chrysler Town and Country sedan 1970 Camaro RS packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=4307&forum=10 aaca.org/ |
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Re: Overdrive Engagement Speed Adjustment
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Just popping in
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It would be great to conduct a survey, and see what everyone's car does under this scenario: Accelerate beyond 22 mph in 2nd, then shift. Did you get 3rd or 3rd OD?
I can't see any reason why you won't get 3rd OD, as you are shifting. Maybe I am missing something. West, I thought we got all of that sludge out of your transmission! (only kidding) Jeff P.S. Unfortunately, I can't join this survey, since torque tube Buicks never have this issue! My loss.
Posted on: 2010/8/24 12:46
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Re: Overdrive Engagement Speed Adjustment
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Home away from home
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The overdrive completes its shift when the torque in the driveline reverses for an instant and the engine is pushed by the car. This happens when you take your foot off the gas for a normal overdrive upshift, or if you are not a little aggressive when making the 2-3 shift. If the car coasts down a hair while you are still in second, the overdrive will engage.
Posted on: 2010/8/24 13:05
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