Penzoil Synthetic is actually one of the best oils you can find. At Bitog Penzoil is number one with all the oil guys and Mobil 1 is number two. Pennzoil 346 users 25.40% of bitogers Mobil 1 263 users 19.30% of bitogers. 45% of the guys who know about oil the most choose those two brands, all other brands account for 55%.
I believe our particular trucks benefit from group 4 and 5 oil with good Moly content. read the synthetic thread for all the information. If I was you I would take them up on that offer but keep in back of your mind if you get a lifter tick then move over to a high molybdenum oil. PS it really needs to be organic Moly that they use in engine oil, not an additive which usually use none soluble moly. If you read the synthetic thread and have questions, shoot me a PM, but nothing wrong with penzoil. Redline and Amsoil are my top two but penzoil is definitely in my top 5, and they do have decent Moly too.
