Then you're in the same boat as me - I'm currently replacing my tranny with a TEP rebuilt unit.
I added two bottles of Lucas - nothing happened with me either.
My band is glazed and I get shuddering during acceleration (as the band slips/grabs/slips/grabs). This is accompanied by relatively dark and HOT AS HELL fluid.
Your TC has no wear friction material. It's a strictly fluid coupling. Your wear parts include fcriction discs, bands, steels etc. But, not the TC.
One way to confirm it's your friction material: if it's worse when warm. The more viscous cold fluid can 'hide' a slipping tranny to some extent.
