OK for the record, I know that there has been plenty written about this. I'm not looking to start any wars. I just have an honest question, and would like opinions.

I changed all the oils in my truck to synthetic about 10K ago. My intention was to do all the drive train with a particular brand of oil that we could call say brand 'A'. In the process there was some miscommunication with a couple of mutual friends. At any rate, in this process I wound up with not only drive line oils, but 5 gallons of brand 'A'.


The dealer of brand 'A' motor oil claims that he has 20K miles on this oil in his truck and it is fine. I'm at 10K, and my DIC is about to tell me it is time to change the oil. I don't have access to someplace for oil analysis. If I do, I don't know it.

I know there is at least one dealer on this forum, and I believe many using this oil. For you these questions come to mind:

after this 10K how often does one 'need' to do an analysis?
Is there some 'rule of thumb' or idea of approximately how many miles I can go before I reach say critical time to change?

I've towed heavy maybe 300 miles on this change. Other than that, it has all been local driving to and from work.

No wars please, I'm just seeking a consensus. I'm not bashing any brands either, just looking for honest info.