'97 A6 Transmission

[BLEVINSBK at aol.com]

   My mother's A6, which I persuaded her to purchase, has developed a 
transmission problem at 75K miles. The upshift from 3rd to 4th takes~ 3 seconds. 
During this delay the revs of the motor increase; when 4th gear does engage it 
comes in with neck jarring force. Any advice on how to proceed or has anyone 
encountered this themselves?
    In the absence of a Bentley: What is the procedure for checking the 
transmission fluid? It has a plug in the side of the transmission pan. I assume you 
take the plug out at a certain fluid temperature and fill until the fluid 
runs out the hole. 
     I see no evidence of any leaks so the fluid should be fine, but I'm 
going to start there.   Thanks for any help, Brian