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Hey guys,

I'm having a weird issue going on with the way my 97 Thunderbird is shifting recently. I had a new street/strip performance transmission from Silverfox Transmissions installed, a 3k stall CircleD torque converter installed, and a 4" Lightweight Aluminum Driveshaft from Dynotech installed recently but even after having them installed my car was shifting just fine like it should. Recently however, whenever I floor it in 3rd gear it will downshift to 2nd like it's supposed to and go through all the way to overdrive normally, but then while my foot is still down full force on the throttle it now downshifts into 3rd and then back into overdrive again. I think it may be an issue with the stock ECU needing to be tuned but if anyone has any idea if it's something else, I would greatly appreciate some feedback.
 

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Check the tps, but it could be the way the shifts are programmed.
They happen by speed and throttle position.
IIRC, it will downshift at 75% throttle.
 
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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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Yes, it will need a tune, but moreover... don't try and do WOT 3-4s. :)

At WOT the shifts are RPM based. Under about 65-70% throttle it's based on TP vs. VS as Grog said. If anything about the driveline has changed - e.g. the car has more power and/or there is a different rear gear in the differential, you'll need a reflash of the PCM to take the different acceleration rate/RPM:VS ratio into account.
 

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As Brandon said, no WOT 3-4' damn special, lol.s, you can break hard parts in the transmission.
People with HP have broken that shaft into three pieces, lol. It's only held on the ends, breaking the middle out is pretty
damn special, lol.
 

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I think in this case, it was versus, or as compared to.
IIRC means "search, for it" lol. IAVO, and increasingly have **** for brains. :)
 
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