ncnichol
Newbie
So I have an 02 short box 1500 Chevy 2 wheel drive. It has a built 6 l in it with a fairly large blower cam. I recently upgraded to a 4L80E with a circle D 3200 stall converter. The plan was to put a Magnuson blower kit on it after the transmission upgrade which I did. Drove it for a month after the transmission swap but before the blower install. Transmission worked great everything worked great. Park the truck put it in the shop installed the blower now it jumps between 3rd and 4th continuously when you shift into drive back and forth back and forth it's crazy. It does it a little bit second to Third but not as bad but it still does it. Wasn't sure if it was the converter locking up and unlocking or actually upshifting and downshifting.. didn't seem like the converter because it starts to do this as soon as it shifts into fourth it hasn't got up to speed yet to shift into converter lockup. But still I needed to check so I plugged in my HP tuners and commanded the torque converter to lock up once it got into high gear, no change still did the same thing so then I unlocked the converter and commanded it to stay in 4th gear no change. I went into the tune file and commanded the converter not to lock up till 256 mph in every gear so essentially eliminating the lockup converter. Still does it. So then I put the tune back so the converter has it to normal settings and I took the truck out on the highway and commanded the converter and 4th and 3rd gear to either be locked or unlocked in all different combinations you can think of nothing changed the problem it just keeps jumping back and forth in and out in and out in and out between 4th and third. Before I parked the truck to put the blower on it was perfect never touched anything to do with the transmission. I'm having trouble finding information on whether the transmission has to be tuned for a blower? My thinking is originally the transmission depended on a vacuum signal.. done through the ECM now but still a vacuum signal. Now it has a blower there is no vacuum would that have anything to do with it? I've gone over everything outside of the transmission shifter cable speed sensor plugs and wiring it has a brand new harness so the plug on the side of the transmission is not leaking it's got brand new Shafer synthetic oil in it. Anyone got any ideas? Also transmission is a new built-in a reputable shop And has all brand new speed sensors ... It has Brand new everything actually ,Every seal and bushing And every other component.
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