So I'm getting ready (finally) to do my 6liter trans cooler and external filter mods. I'll also be doing a transmission filter (oem motorcraft) and flush.
My question is...
What fluid to use.

Ford has motorcraft fluid for 5.33
walmart has "supertec" for 3.77
walmart has royal purple for 8.60
napa has royal purple in the same range
napa has their brand mercon v for close to ford price
advance is where I can get a deal on royal purple for about 4$ a quart

I have not found a schaeffer dealer close to Maine and have not searched for one near philidelphia yet.

Where else can I get fluid and what brand do you guys reccomend.

 

I buy the Coastal synthetic Mercon 5 at Autozoo.$4-$5 a qt

 

Last time I saw John Wood he told me to use Valvoline Max Life Synthetic so I did. It's pricey like all synth but like John said "That's what I use and what's another couple years on an old tranny worth?" NAPA has it.

Doing mama's 2000 Ex this weekend s it's due for a refresher.

 

I also used the Valvoline synthetic. Bought from Fleet Farm here in MN.

 

I agree, it's tough to decide. I went through the same issue myself a short while ago. I ended up just getting the Mercon V from Motorcraft because it's available all over the place and easy to get more if I need it. The other stuff would be hard to find if I had an issue while traveling.

Plus, I had a real hard time getting a straight answer from the vendors what I could and could not use. The guy at NAPA told me that the Valvoline Max Life was fully synthetic but it wasn't labeled anywhere on the bottle. The catalog said it was synthetic but the picture in the book showed a bottle with 'synthetic' on the label and it looked different than what they had on the shelf. I then went to the dealer and they said that Motorcraft Mercon V was synthetic but again same story as Valvoline....nothing was labeled on the bottle to say it was or wasn't. I then went over to the Ford medium and heavy truck service center and asked those guys. They thought that at one time there was a semi-synthetic blend as well as a fully synthetic Mercon V product but now it's all fully synthetic. One guy even suspected that all ATV should be synthetic by default because none of it looks like it's made from petroleum anyway.

In the end, the person at the Motorcraft parts counter picked up the phone and called somebody (don't know who). The response was that Motorcraft Mercon V was a semi-synthetic blend and good to use for my trans even though is says to use normal Mercon (but I already knew that last part anyway....). So, I gave up trying to learn about ATV and what brands might be better than others and yadda yadda yadda and just bought a couple of cases and left with the small amount of sanity that was left in my head.

So I am using Mercon V mystery fluid and it's working fine.