Shudder upon acceleration and shifting from 1st to 2nd

I bought a 1991 Dodge Shadow from a private owner and he told me it needed a trans mount but upon inspection the mount seems to be fine the car will shudder upon first acceleration and a louder shudder shifting from 1st to 2nd. So I was leaning more towards a cv axle rather than the transmission mount still not sure. Only have this problem under a load 60-65 mph seems to drive fine and no viberations!!!

My best guess is a sticking 1st-2nd shift solenoid. Maybe a fluid change will help. Maybe a solenoid change will be required. Maybe transman will see this post and reply with a more professional opinion.