Changed OS now 4l80 won't Shift

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Apr 20, 2017 | 08:17 PM

Monte4ever

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From: MI

Changed OS now 4l80 won't Shift

Been using 4L80e for years without a problem. I changed to a Flex Fuel 2bar OS (12216125) and did the 4L80e segment swap for the OS but now the trans will not shift. When I put it in gear for the first time it will shift normally, then after coming to a complete stop it will not go to first and seems to be stuck in second. When I command any gear with the scanner they all engage while moving. I don't have a log of the problem but any suggestion of what's going on is appreciated.

Last edited by Monte4ever; Apr 21, 2017 at 03:35 AM.

Apr 22, 2017 | 08:02 PM

joecar

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From: So.Cal.

Have you looked at the PT mph shift tables and the throttle kickdown tables...?

Apr 23, 2017 | 09:53 PM

SlasherVRGR

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From: NEPA

I'd be sure to copy and paste all of the previous trans shift pressures and variables from the old tune to the new one.

Apr 28, 2017 | 07:39 AM