The new grey gaskets from cummins SUCKS! Once the greys' get oil on them they turn real gummy and stretch out... very hard to work with when trying to reinstall them when working on your engine later. Call around to some diesel repair shops in your area and try and get the black gaskets that come in an orange package. Those kind do harden up after 100k miles of use, but they do not turn gummy and stretch out!
-Mike