gear box oil

hi guys , could someone tell me the gear box oil for the California please , how much it takes also is it a straight forward job or do you need any special tools

 

thanks for the reply, to be honest I am a bit worried, I put a deposit on a 2012 model last week with 31,000 miles, when I got home a noticed a 2011 model near me so I went to see, its got 18,000 miles, the 2012 model has some slight marks on the paint , all the wheels needs doing which he agreed to do ,he has receipts to show that the gear box speed sensor has been done at a cost of around 7k, the 2011 model is mint all over, but the gear box has not been done, the chap selling the 2012 model is saying I am stupid buying that other one because its only a matter of time the gear box will go, so I thought just as a precaution change the oil, is he correct or just trying top get me to change my mind and buy his
can someone put my mind at rest please

 

sorry I forgot to add , I pick in up next week