p1870 code after I replaced Valvebody. I need help and answers.

[bmw1997]

97’ Gmc k1500 4l60e
This is my first truck and I can’t afford to bring it into a shop. truck shot the p1870 code few months ago and had hard 1-2 shift, I then replaced TCC Valve with a fitzall part and all shift solenoids. it fixed my problem for a few months then the code showed up again. i replaced the valve body with one from cyclone transmission. when i took off the old separator plate i noticed the 1-2 check ball stuck in the separator plate and the plate was noticeably worn. put the new valve body on and the truck shifts buttery smooth now but i still have the same problem, the 1-2 shift SLAMS after the tranny is hot and or after highway miles for about 15 minutes. the other shifts are firm as well. I need a solution please. Thank you in advance.

(i maybe think it has to do something with a faulty pressure regulator-i’m very young and do the work myself and hoping there is something else i can try to help fix this.)

-ben

 

[Schurkey]

Did you change the separator plate? Did you replace the check balls? Did you install a valve body that's correct for your vehicle?

Download the free '97 service manual from the link on this web site, follow the diagnostic procedure for P1870.

 

[bmw1997]

Did you change the separator plate? Did you replace the check balls? Did you install a valve body that's correct for your vehicle?

Download the free '97 service manual from the link on this web site, follow the diagnostic procedure for P1870.

replaced the seperator plate and the valve body is correct for the vehicle. i did not replace the balls, they didn’t look like they needed replaced but i’ll look into the diagnostic.