Well I had the same prob with my 84 Cj it would shudder on take off... I made the mistake of buying a new trans $2000.00 DO NOT DO THAT
I found out that after I changed my spark plugs and cleaned all my grounds aloso adding two new ones, changed all my vaccume lines it stopped!!!! If your current dosent have good groung you dont get the best spark!!! Trust me try the little things first.. If you engine is dirty like mine was after I bought it clean it up and do some big maintnence... Dont buy crap till you do thoes things I said or youll kick yourself in the *** later... Hope that helps..