dot 3 is cheap up front;...until the rot sits in on the tail in. dot 3 keeps the parts people in business. i've never owned a mopar that used dot 3 that didn't have the master cylinder rot and leakage. ever see a firewall on an older mopar that still had paint on it below the master cylinder? i took a chance with dot 5 27yrs ago and glad i did. i remember some years back on this website where this issue was brought up and the claim that dot 5 screws up the rubber parts in the system. i got to thinking that i had dot 5 in my car for maybe 15yrs so i'll take the system apart and look for damage. there wasn't any hint of damage to the rubber parts and the cast iron master and wheel cylinders were like new. can't say that for dot 3. how long does it take for dot 3 to make all the cast iron parts look like a cat crapped in them?