my 03 2500 4x4 has 86k on the clock and has had very little in way of service done so far other than oil changes every 5k and trans. fluid 2x now and u-joints replaced at 30k, and the t-case fluids changed 1x. the a/c has to be charged every year cause the leak is so small they can't find it. but thats about it. brakes are still fairly good. don't i need to get the valve lash adjusted at 100k or ??? THANKS for the help.