There are a few threads already with good info about the tranny repair. At this point I will be trying this DIY
Project #23: ZF 5HP18 Transmission Valve Body Overhaul DIY Part 1
which is for a smaller tranny but it should be similar. I am open to any tips and suggestions.
I am attempting this 'repair' because I have a hard downshift from 2-1st when warms up but it runs well when cold and a hard upshift from 3-4 when it's warm.
I just hope for some improvement and if not I guess I will have to take the tranny down and follow Louis path.

I bought this kit: Valve Body Kit, ZF5HP24 (OEM) [D139165] - $180.99 : Automatic, Standard Transmission and Transfer Case Rebuild Kits, Cobra Transmission Parts 1-800-293-1848

Wish me luck!