Is your NSS working properly?

I hate to be the bearer of bad news but my trans had the exact same issues your having before mine blew.

 

My entire harness from the Solenoid pack and MLPS up to the 2 molex plugs under the brake booster is new.

I'm still thinking something is making SS1 not open the circuit. PCM is new though.

 

Hey everyone. Sorry I haven't been on in a while.
Yesterday was my first chance to take a whack at it since I last logged on. Works been eating up my time.

As it turns out my valve bodies keep getting stuck. They've been polished and cleaned out very thoroughly. But I'm starting to think the new oil I had used is not the right one. I used Castrol Dex/Merc because the bottle said it was the closest thing to straight Mercon.
Which oil is the best for this trans?

 

Dex/Merc should be fine. MERCON V has replaced Dex/Merc and is now the proper fluid. The Castrol fluid you used is not the cause of your problem.

 

So after dropping the valve body for the 7th time, polishing the valves, polishing the bodies, cleaning the valves and bodies with carb cleaner, flushing the whole system with new oil almost every time I took off the valve bodies, new filter, SHE FINALLY SHIFTED into all gears perfectly! Oh boy oh boy, I'm excited lol.

Thank you all for yalls help!

 

Congratulations on the resolution. Maybe this time the flush loosened and removed some debris from the passages. At least it's working properly now. Persistence is key.