If it is an aluminum or steel deck 215 that has shaft drive- it was designed to remain sealed for the life of the unit. That said, you can pull the trans and split the case, clean it out and refill with similar lubricant.
If it is a poly deck 215 that uses a belt - the bottom of the case can be removed.
You need a 00 grease to lube these transmissions. Snapper, Stens, Rotary all package 00, as well Castrol has a nice 00 SHL synthetic.
Information required can be founf in the owner's manual, it is too lengthy to submit in this arena. Please see links.
Put a 9/16 box wrench on it and snap it hard in the right direction. (counterclockwise) You might want to hit the bolt with a hammer once or twice to "break" it loose.