How many miles? I'm assuming you don't have a shift kit in it? If not, you could put one in, and inspect the oring on the 2-3 piston, and make sure the bore in the 2-3 accumulator isn't glazed. That could be the issue. I'd start there. That definitely doesn't sound normal.

If that doesn't fix it, there could be a problem with certain clutches being worn out, or low pressure delivery to those clutches.