4L60E no 2nd after rebuild

[bbarlow88]

Hello all. New here, not new to the transmission world though. Recently rebuilt a 4L60E out of an 04 1500. Having a strange issue. If I unplug case connector I have Manual 2nd and 3rd. However if I plug in case connector it shifts 1,3,4 with no 2nd. I can see that the PCM is commanding 2nd and the 1-2 solenoid switches off but the 1-2 shift never happens. It stays in 1st until the throttle is released and then shifts to 3rd. Any ideas? 1-2 shift valve sticking?

[sefiroxx]

Took a look through the tech manual, I would look at the 1-2 valve. There is a spring that is supposed to return the valve when the solenoid is turned off for 2nd gear. In 3rd, the spring gets assistance from atf pressure so this might explain why 3rd etc.

 

Also, one of the checkbooks might not be seating or blew through

 

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