Ok, after reading your post to SHOTimes, I'm sorry to say your tranny needs to go back to the shop.
Unfortunately, even the most "rock solid" tranny rebuilds can be a dud right out of the shop. The only way to really avoid this is to use a tranny shop that has a tranny dyno where the tranny can be run through it's paces for several hours before being reinstalled in a car. Even the best tranny shops can give you back a bad tranny. We recently had a tranny shop that we trust completely and have never before had a problem with rebuild a GM THM350 tranny, which is about the simplest tranny in the world to rebuild, and it came back worse than before the rebuild. If your tranny feels like it's slipping, it's slipping.
Another thing you mention in your SHOTimes post is that you have a '95 AX4N tranny. If that is true, then you have a SLO tranny, NOT a SHO tranny. The AX4N was not available for the SHO until the '96-'99 SHO's, and they are not compatible with the V6 SHO bellhousing pattern, electronics, etc.
Since you seem to have other motor issues, you might want to address those before bringing the car back to the tranny shop (tranny shops love to blame tranny operational issues on anything but the tranny when they can). Then bring it back and see if you can get them to do the R&R labor the second time around since the screwup is their's.