Auto Trans problems 1996 318ti

Any advice would be appreciated (other than someone saynig "take it to a shop")
In 4th gear I am not getting full lockup. I can move to neutral at
highway speeds, then back to 4th and the rpm's are where they should be. Then after 3 or so seconds the transmission seems to shift down a half step between 3rd and 4th gears. The fluid is good, no slippage. I think this is an electronic problem. Help!!!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.