The string 'manual' is never going to equal the string 'Transition Type'.
You cannot reference a variable with a string literal. If you want to use non-valid names for your variables you need to reference them using name literals.
if "Transmission Type"n = 'manual' then Newvar = '0';
But to make your coding much easier just change the setting of the VALIDVARNAME option to V7 instead of ANY before you run the PROC IMPORT. Then PROC IMPORT will create valid SAS names for the variables in your XLS file that have headers that are not valid SAS names..
if Transmission_Type = 'manual' then Newvar = '0';