Took the Dmax in today for the third time for a leaky Hydro-Boost. Dealer says it's definitely the Hydro Boost (like I've been telling them for months now). They say they tried to order the part but GM had discontinued the part number and the new units won't be released until sometime in October. My truck is a 2002 you may want to check yours for leaks. Feel under the brake fluid reservoir towad the back of the unit where it bolts to the booster there should be a small rectangular opening. Mine leaves small amount of fluid on finger every couple of days.

Matt B.