Transmission noise

This is not the sensor cycling every few seconds which I can hear and feel on top of the transmission.

Problem is when in gear stopped at traffic light or in driveway, can hear a bump on top of transmission, and a light scraping noise, both of which go and come, and both of which go away when shifted to neutral or park. When driving down the street, the light scraping sounds like a limb hung under van and scraping the pavement.

No dip stick to check transmission fluid level. If I put a small rod down tube, what depth should fluid level read?
Or is there a better way to check fluid level?
Will Lucas transmission or other product help?
Just got van three weeks ago don't have any idea how long it has been this way. Previous owner practically deaf and probably never heard anything!
Thank you for your help and ideas.