Hi, I am fully aware that this is a Chevrolet forum, but I know that people drive other brands too. My question relates to the transmission, but first I need to tell you about the truck. It is a 2000 f250 with the 7.3 L Power Stroke, 4x4, automatic transmission, just rolled over 200k, and the trans was rebuild about 15k ago. We recently realized that we are at the time where we should be considering changing the fluid, at this time that last 15k on the trans have proably been about half towing and have commuting. What I want to know is can we use the newer mercon 6 fluid? From the factory it took Mercon 3, but that is no longer produced. Supposedly it is backwards compatable but in a little looking around we have done we have heard horror stories of doing such. I hope some of you out their can give some advice, or help me weed through the B.S.

Thank you!