SixtySix

Back to the original question of it being a sealed system and the dealer saying that they can't service it.

Find another place to have your car worked on, they have no idea what they are talking about. Heck, it's part of the 30k service depending on which schedule you go by.

ravenblack67

The 5R55S uses Mercon V and is designed to be maintenance free under normal use. We remanufacture this unit for Ford and very very few come in for warranty. The drain and fill procedure is not something you do at home. Unlike engine oil, Mercon V will last a very long time unless the engine and transmission are overheated. My 2005 Mustang will get a fluid change at 100,000 miles.

theedge67

Well that should settle it. Thanks for the info Ravenblack67!!

metroplex

While ATF does not get contaminated (as fast) as engine oil, the friction modifiers WILL break down, especially in a Group II/III blend or a Group III "synthetic" ATF basestock such as the one found in Mercon-V. Once the FM breaksdown, the clutches inside the auto will wear down and overheat. The torque converter lockup clutch(es) would then start to chatter and cause the dreaded shudder.

Now, if you drive like a 60+ year old man, you may never need to change the ATF. If you drag race or drive aggressively (do any WOT forced downshifts?), it may need a change.

I'm not sure what magical components Ford used in the 5R55S to allow for a lifetime fill. Mercon-V is the same stuff used in 4R70Ws that has to be changed every 30k miles, and the same stuff that still allowed the dreaded shudder in earlier 4R70Ws.

Ford's idea of lifetime could be 5 years / 100k miles of normal driving. If you can change the ATF in the 5R55S, consider doing it. Even if it is just dropping 4-5 quarts, it would be better than never changing it.

A manual transmission is a different beast altogether, yet Ford still recommends 60k service intervals for severe duty. Tremec claims the gearboxes are lubed for life at the factory but conveniently installed drain and fill plugs.

lodom

I think around $80 is inexpensive preventative maintenance for a trans that would probably cost $2000 to have swapped out. Ford and other manufacturers are competing on the 100,000 mile service interval to sell cars. I'm not in favor of running spark plugs or any engine fluid that long.

SixtySix

Yeah, under severe duty Ford calls for the tranny flush at 30k. I drag race my car, drive it like I stole it and can tell when it's getting a little stale. I also drive in the hottest climate in the US and in lots of dust with a nice mix of bumper to bumper traffic.

I changed mine out at a little over 15k because it was starting to feel a little soft, and as I expected, everything was right as rain afterwards. So pay attention to what the car is telling you as well in addition to what the Ford recommendations are

Northwest GT

Hey Louie, thanks for posting those PDF's.