So Shell T 6 is a group III oil and Mobil 1'S truck is a group IV which up here the Shell is some $33.00 a 5 lilter jug and the Mobil is $46.00 a 4.4 lilter jug at wallymart I believe. Some out here seem to think the Shell is gods gift to TDI's. It sounds good but is really that great as everyone claims it to be?? What is the Zinc content etc., in the T 6, or does anyone know??? Each their own, we all I am sure have our fav., as to what we like to use. I am just trying to see if there is something better then the Amsoil I am using and at same time less money out of my pocket plus easier to get, as I can walk into a Wallymart and pick it up. Sounds to me both are twice what one pays south of the border and the fact that we are getting ripped off big time up here. Need to do some cross border shopping some time soon maybe and if the Shell is really all that great get me a case or two. Will use the Shell as the Amsoil is a little costly. May save even on Amsoil as I use the AMO 10W40 with the high Zinc etc., in it, in my 2006 Jetta PD TDI. Everyone have a great day eh.