Genuine Ford Fluid XT-M5-QS Full Synthetic Manual Transmission Fluid ...... any of you guys tried this in a 2004 6 speed? local ford dealer is saying this is the new and improved stuff to go with. its pretty expensive at 20 bucks a quart.

 

That price sounds ridiculous. Synthetic trans fluid is the way to go but not at that price. Check ebay for the same stuff to check the price. Just be thankful it's not a automatic. LOL
Update!!!
I just checked ebay for myself and $20 is cheap. This stuff must have gold flakes in every bottle.

 

Owners manual calls for Mercon atf for the 6 speed manual and 4r100. They no longer make Mercon it was replaced by Mercon v. I'm not sure if that's the same thing as the transfer case fluid that is rebranded Mercon or what but I would do some checking before I dumped it the trans. According to the book as longer as the fluid meets the specs for Mercon your good which Mercon v does valvoline has a synthetic fluid that meets Mercon specs including v sp and lv.

 

Mike has the right idea. Regular Mercon ATF is specified in your owner's manual, and that's what I use. Mercon V replaced Mercon, and that's the only thing I would put into your transmission. Good news for you, it can be had quite cheaply.