Could it be low of fluid?
Let it warm up, good and hot to operating temp, then idle some more (should be something like 17 minutes driving). Since you can't drive you're gonna have to let it idle a long time to get the tranny fluid hot. Once the fluid is heated then check the level.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.