Trans weirdness

[chandlerGTi]

1991 300te 4matic.

While pulling away from the curb it revved up to about 5000rpm still going about 15mph. It has also suddenly revved up while driving down the road. Car has 200k(ish), trans has about 95k.

Seems like it is slipping but it is at odd times, anything particular to look at? Trans was drained and refilled (new filter) with Fuchs full synthetic in September of last year, fluid levels are good.