The part that Johnd89 mentioned probably won't help you. That valve controls the on off function for the tcc. Your tcc is turning on. The problem is low apply pressure for the clutch. This is the part that would most likely help you.
Sonnax Transmission, Torque Converter, Performance, Driveline Parts :: Transmission :: 84754-01K :: Part Summary
This valve has extreme wear since it constantly buzzes in the bore while tcc is engaged. The other valve just clunks back and forth for engagement and disengagement.
I do not recommend going into the valvebody unless you have experience working on trannies. I have seen many people in the trade make mistakes.
But if you do try, Make sure you have new valvebody gaskets ready. And don't lose any of the check balls that will fall out.