PAULUNM

Exxon Mobil would not tell me what the difference was. All I know is that the spec sheets you can pull off their website show the oils ARE different. IIRC they have different flash points- so something is different about the oils.

I believe the zinc and phosphorous ppm is limited to the same number for both oils- but I can't be sure as I have not been able to find that info for D1.

All they told me was that D1 is approved by all the big diesel mfrs, and TDT is not- so she eluded to the D1 being a heavier duty oil. It was a pretty worthless conversation to be honest with you.

The D1 seemed to make a huge difference in the way my 2.0t GTI motor FEELS- but I could just be imagining things.

PAULUNM

Kevin, I used the commercial oil finder on the ExxonMobil website to find The Jankovich Company, locally here in Los Angeles. You can order online, but shipping 4 gallons is expensive!

Here's their online distributor finder- most of their distributors don't require a commercial account with them. Check the box "Commercial Vehicle Lubes"

http://www.host.exxonmobil.com/chann..._directory.jsp

I paid around $150 for 4 gallons- which works out to be under $10 a quart.

Here's the address for Jankovich-

http://www.yellowpages.com/paramount...p?lid=16873624

AVLube.com sells D1 ESP-

http://store.avlube.com/fonfacsizcol.html