Re: Maintenance at 15k???
Follow the owner's manual recommendations. I don't think Jeep recommends a diff fluid change, at least in the first 120k miles unless you drive off road al the time or use it as a taxi. Varies by model, however.
2011 WK2 Overland Mineral Gray/Black, Advanced warning, V8; 2009 KK Rocky Mtn V6; 2000 WJ Laredo I6; 1979 CJ7 I6... green... miles of smiles :)