do a google search... there's hundreds of write ups on changing the M90, M62 supercharger oil

if you're going to do that... i recommend getting a "green" coupler and replacing the crappy black one... the black one wears down and contaminates the oil and hurts parts in your s/c overtime....

the green couplers can be found on ebay for under $20 and I bought mine for $10 in the classifieds