Frist drain the oil out of the planatery & then remove the crome ring on the outside. Then in the middle of the planatery you will find a cap that looks like a nut remove it, and behind that is where you will find another nut it will be different than the frist one .Look very carefull and you will see a piece that you will need to fold down from the spanner nut with a small scewdriver it locks the nut in place. Then look very very hard in the middle of the nut you will see a small screw that you will need a allen wrench to remove it.Then you can remove the planatry.
Going back in whach out for the oil pump going back in,that is the little fiber gear.Be carefull,Then refill with 90/140 gear oil.Fill untill a little comes back out of the hole on the side of the planatery.