Should be fairly easy/straight forward to take the shell off and grease everything up. Remove the armature from the motor and grease the bearings. Pop the cover off the worm wheel and grease the worm and worm gear. Don't forget to oil the drive wheel bearings and the side rods.
Everyone will give their opinion on grease and oil and what common stuff you can use from the auto parts/home improvement store. I stick with Labelle 106 grease and Labelle 107 oil. They are designed for models and work very well. It's more expensive per ounce than the adapted stuff but it's designed specifically for model trains.
