transmission problems? stuck in 3'rd gear
 

hey ,
i blew a water pump seal again and i changed it and drained all the milky oil and flushed it a cpl times.installed a new oil filter and oil.now it wont change right , it's not slipping out of gear ,it's stuck in third.i got it in neutral and was reving it up and it jumped into first gear! does anyone know what could be wrong ? i wanted some info before i go and splitting the case.thanks.