I don't know if the dishwasher would hurt it or not, but I definitely wouldn't do it. I just finished washing/drying/relubing an old peanut this morning. Only took a few minutes to do. Just hold the knife down under warm soapy water, open/close each blade a few times and the use a brush to clean out the liners and the back side of the gap that's open when the blade is half open.
Then I dried it with a hairdryer, took it outside and soaked it down with WD-40. Let the WD-40 dry, then wipe it down. I rewashed just the blades (so its clean if it comes into contact with food), then put Mineral Oil in the joints and on the blade and opened/closed the blades a few more times before wiping down with a clean cloth.
Good as new!