Tranny Shifting wierd (4l80e)

Been putting a lot of miles on the truck latley, LOVE IT! I have noticed an issue with the trans though.

When I start it up and drive it for the first time each day, it acts like it doesnt want to shift out of 1st. Its not slipping, its just acting like it doesn't want to shift at the reg RPMS...instead it shifts around 3-4k and then from there on it shifts fine. Like even if I stop at a stop light, it will shift regularly after that. Its just the first initial shift for driving the truck each day. It does have a Nelson Tune and they have the shifts firmed up I am not sure if that matters.

And also, if I shut the truck off after driving fora bit and let it sit, it wont wanna shift out of first but once it does everything is fine and like I said every shift is fine after that whether its from a stop sign or not. Ideas? Fluid is good.

I think you run on cold shift point until the trans reach its normal operating temperature... Can someone confirm this? According to the nice schematic Redhearbeat post on your thread, the trans have a temperature sensor built in.http://www.ls1truck.com/forums/lsx-t...-build-16.html

They have a temp but there is no cold shift table.

Ok what about this: When It doesnt want to shift out of first when I first drive it, I manually put the column shifter in 2nd and it will shift right there and then. But when I manually put the shifter on "D" again it will downshift back into first

Upshift sylonoid my b getting weak

Quote:

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Originally Posted by LQ9_Z71

Upshift sylonoid my b getting weak

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How easy is that to do. Trannys r the only thing I don't really kno about.