Does your engine rev 100 rpms before OD?
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Joined: Mar 2007
Posts: 10,101
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From: Pa
Originally Posted by douglee25
On my '99 SD I've seen my engine rev maybe 50 - 100 rpms just prior to going into overdrive?
Normal?
Thanks again.
Doug
Normal?
Thanks again.
Doug
Sounds like something in the tranny is slipping or something with the tach.
Last edited by dkf; Jul 13, 2007 at 06:22 PM.
Senior User
Joined: Mar 2007
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From: Montana
Mine does that too. Also I had a f150 that did that the entire nine years that I had it. I believe the line preasure in the tranny is limited to make the shift feel smooth. but this does allow for some slippage. A programmer can change this if you want to firm up the shifting.
Budman
Budman
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From: Long Island USA
Torque converter is locked up in 3rd gear. When it goes into OD, it has to unclutch the torque converter, shift into OD, and then after a few seconds, lockup the converter again. Otherwise, it would go BANG into OD 
My '01, I think, does something similar.
The shift strategy may have been changed in a later year, so comparing a '99 to an '04, the '04 might not do the exact same thing.
My '01, I think, does something similar.
The shift strategy may have been changed in a later year, so comparing a '99 to an '04, the '04 might not do the exact same thing.
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Joined: Mar 2007
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Originally Posted by krewat
Torque converter is locked up in 3rd gear. When it goes into OD, it has to unclutch the torque converter, shift into OD, and then after a few seconds, lockup the converter again. Otherwise, it would go BANG into OD
My '01, I think, does something similar.
The shift strategy may have been changed in a later year, so comparing a '99 to an '04, the '04 might not do the exact same thing.
My '01, I think, does something similar.
The shift strategy may have been changed in a later year, so comparing a '99 to an '04, the '04 might not do the exact same thing.
Doug
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From: Home Base Nebraska
Originally Posted by douglee25
On my '99 SD I've seen my engine rev maybe 50 - 100 rpms just prior to going into overdrive?
Normal?
Thanks again.
Doug
Normal?
Thanks again.
Doug
Denny
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Joined: Mar 2007
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Originally Posted by rvpuller
This is normal and it will also do it going into 2nd and 3rd if you are putting a lot of load on it. The time before is locks the converter changes with trans temperature. The hotter the trans temp the shorter the time before it locks the converter (less heat buildup with a locked converter).
Denny
Denny
Doug