Gotta say I gave it a shot with the M1 TDT after class this morning and I'm impressed. Added a quart of Lucas synthetic stabilizer with a napa gold 1515 filter and it really cut down on engine noise. I think it's running smoother too.

 

I go bigger filter on my 04 because it lacks the oil cooler that the 99-02 have. I go regular size on my 99.

May make no difference but it makes me feel better.

 

I had a similar result with the TDT. It's definitely nice oil, and I really think being full synth makes a difference.

With the filter, I see your point. I didn't know the 03-04 lacked the oil cooler. Some of those monster filters have a higher bypass pressure which makes me nervous because I suspect they deprive the truck of oil at times. But the 51515 is the same bypass pressure as a stock filter, so I don't see how it could hurt anything.

 

My 99 leaked like crazy when I switched to Synth. I switched back and it stopped after a couple of changes. Some leak and some don't ???