You will find many opinions here on lubes and oil. Some even use diesel oil(synthetic and petroleum based) and are happy. I have used Amsoil products with very good results since 1976. It's been in my car since new. I will changing the transmission and differential to it this spring.
IMO, the decision by Chrsyler to use Mobil and Castrol products has a lot more to do with marketing than anything else. If you do a little search, you will find some 'spirited' discussion in this area. Tom, 'the oil guy,' is probably the most knowledgeable guy on this subject in this forum. He works in the oil industry. He uses petroleum based diesel oil, in part, because of the additional additive package it contains. You will have to do a little DD and make up your own mind. Suffice it to say, there are definite alternatives to the factory fill.
Steve
