I have a clunking sound on the downshift of my 84 300DT( 256K) and i want to know if I change all the vacuum lines will this eventually solve my problem. How much is the whole vacuum repair kit?I do not know how to use the mityvac...is there a DIY illustration somewhere to test the w123 vac system? Will this clunking affect my tranny eventually?I have the original still on there. Thanks .