727 won't shift out of low after rebuild

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Yellow Duster

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This is in my 79 wife's Power Wagon. I installed a new 360, and while it was out, I refreshed the trans and transfer case. The trans worked fine but had plenty of leaks. When I tore into it, it was in relly good condition, possibly rebuilt in the past. I replaced everything since I had the parts. I also installed a Trans-go dash 1 kit. I put in a new TC, radiator with cooler and flushed the cooler lines. Got it running and filled with fluid. Goes into drive and reverse and drives around but will not shift out of low. Have put it in all forward postions with no change. The kick down was adjusted correctly before driving. I backed it off some and nothing changed. I tested line pressure and it matches the service manual numbers, 58 psi to 90 psi. The rear servo pressure matches that in low 1 range. I have not yet checked return line pressure or governor pressure. I'll have to get stuff to make a cooler line tee. Any guidance before I pull the pan and valve body? By the way, new engine runs great, can't wait to go ripping down the road!
 
It sounds governor related. I would check the governor pressure and the return line pressure before pulling the valve body. I’d also get a pressure check on the kickdown/front servo. That will help you eliminate if the servo is even trying to apply or not. Did you do any air checks before final assembly?
 

I did all the air checks and they were good. I did check the front servo and didn't have pressure, but the service manual shows it has to shift into 3rd to have pressure there.
 
I did all the air checks and they were good. I did check the front servo and didn't have pressure, but the service manual shows it has to shift into 3rd to have pressure there.
That is confusing to me.

The front servo is applied when the car shifts into 2nd gear. That is what applies the 2nd gear band and stops the sunshell and direct drum from spinning. It shouldn’t have pressure in first or third but in second it should have pressure. Since yours won’t shift to 2nd, it sounds governor or valve body related. Only reason I asked about the pressure of the front servo is because if it was seeing pressure but the car wasn’t shifting, then there could have been a broken band lever, band tab, broken strut. So since there’s no pressure, that confirms it’s not shifting, opposed to it’s trying to shift but the band hasn’t been applied via the servo.

Give update after you check governor pressure and line pressure. I’m not super familiar with the trans go kits as I don’t use them, but I know if anything is not correct in a valve body, the trans will do crazy things.
 
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