I've always changed transmission filter every 30k or so miles. I bought this truck with 56k and the dipstick still looked bright red so I assumed the dealer changed it before I bought it. They would not tell me what all they did to it (another reason I won't go back to that dealership, but don't get me started) it's at almost 70k now, and I'm doubting myself for not changing it at 60k. I looked in the owner's manual and it lists changing the fluid/filter for a whole list of transmissions, but the 4r70w is not on there. I've also got a Ford repair DVD and it has nothing about how to drain the torque converter, just how to change the filter. So, I was going to just change the filter and the 5 quarts that is lost changing the filter. However, now after I've read all of this stuff in the book, I'm wondering if there even is a change interval on it. Anyone know? Since the torque converter doesn't have a drain plug on it, I'd assume it is not something that requires normal draining. The truck is an 04 heritage, 4.2L. I don't do any towing and hauling is maybe once or twice a month with max a couple hundred pounds (a few sheets of plywood and lumber) Should I just return the filter and fluid and don't worry about it, or what? Isn't Mercon V synthetic requiring less service intervals?

 

To completely change the fluid, have the dealer or a good shop do a fluid exchange. There are several posts on here detailing how you can do this yourself, with a partner. Dropping the pan and replacing those 5 or 6 quarts changes less than 1/2 the fluid, so that is not the way to go. On my 4x4 '01, that changes only 1/3 of the fluid, but I do have a drain on my TC. Even then, there is probably another 2 quarts or so in the valve body, servos, accumulators, and the coolers and lines.
Service intervals are quite long, but like anything a little insurance is cheap. Get a complete fluid exchange (not flush) and enjoy some piece of mind.

 

The 04 does not have a TC drain, so you have to use an exchange machine or other method to change it.

Officially, the change interval is 150k under "normal" service and 30k under "severe" service. Mercon V is not necessarily synthetic - it's a blend. However, full synthetic that meets Mercon V specs is available.

If you don't mind spending the 100 bucks or so to do it right, go get it done with an exchange machine. However, if they try to sell you a chemical flush with it, take a pass on that.

 

hmmm...if the "official" interval is 150k, maybe I'll just wait and do it all at 100k. I'm actually looking at other trucks, so I may only have this one another 10k miles or so. The greatest majority of driving is non-loaded highway driving anyway.