Quick follow up to my (delayed) project (I hate it when life gets in the way!). Pulled the VB on the extra trans I bought to exchange w/ the rebuilt VB I purchased from Central Valve Bodies. VB gasket was blown on the old one. Got the new vehicle up on the rack and pulled the pan, pulled the VB and it had the new bonded gasket, so am assuming there has been some work done on this trans since the bonded gasket isn't original equipment on '98 5R55Es? Pulled the Reverse Servo cover and pushed up on the servo itself. After squirting out all the fluid, it just bottomed out. Went and tested the spare transmission's reverse band and it had plenty of return spring to it. Soooo, as CDW6212R pointed out, my reverse band is shot. Pulled the trans, ordered a full rebuild kit (steels, frictions, rubber, gaskets, filter, 3 bands, bushings) and of course, got the wrong application, so am currently returning it, waiting on the proper application. That, along w/ several 5R55E transmission specialty tools from 'blackhatauctions' on eBay and the LubeGuard Seal-E-Zee kit, am hoping to have a gutted and rebuilt trans in the next two weeks.
Again, excellent/invaluable advice from several 'rock stars' on this list. My thanks to those who are willing to share their valuable time and expertise to others.
More to follow as the (delayed) project progresses!