I am about to drop the pan on my '98 Expedition 5.4 with the E40D Tranny. The book says it uses Mercon fluid and the dipstick also simply says Mercon on it. I was thinking when I ran and purchased the fluid that it was Mercon V until I took a closer look at it. However, the fluid I purchased was Valvoline Mercon V for '96 and newer Ford's. It says on the back of the bottle that it meets both Mercon and Mercon V requirements? Is this ok to mix with the straight mercon that is in the transmission from the factory?
My Taurus owners manual says dual rated fluids are ok for Mercon V. I am confused with it, so I stay with a single rated fluid. I would recommend taking the dual rated back and get some Mercon. If you have the E4OD, it is finicky and does like regular Mercon.
There is a never ending debate on this single rated vs dual rated Mercon thing. I sure wish there was a definitive answer. I am runing Redline D4 (dual rated) in an A4LD, but I was scared to do it to my 1990 E4OD as I heard the E4OD is the critical one for fluid type tollerance. So I am running Mobil 1 Mercon ATF in the E4OD. But then the guy at Redline says that's just Ford's way of getting you to buy their fluid. Who knows?
When I last time checked ATF prices, comparable fluids of different types (i.e. F, Mercon, etc. of a same brand) all had the same prices, so there's no reason to go with a different type of ATF. Of course, if some company doesn't make all the fluid then that might be an issue.
I can understand how a transmission might prefer one type of fluid over another. A search of this forum would turn up a few previous posts by me describing how disappointed I was with my Ranger's 5R55E tranny after it had been filled with Valvoline's dual-rated Durablend ATF. When I flushed the dual-rated stuff out and put in straight Castrol Mercon V (recommended and approved by Ford), the 5R55E's performance improved significantly.
IMO it's the dual-rated fluids that are helping to confuse the issue. The manufacturers of these products claim they "exceed" both Mercon AND Mercon V specs. Yet many times these "hybrids" just don't work as well as advertised.
In any case, if people say nothing but regular Mercon for the E4OD because that's what it prefers, I can easily go along with that.
So dual rated Transmission fluid in general is not a good idea from what I see in the posts? What about the standard Dexron III, Mercon dual rated fluid? That is about the only thing you really see at stores around here. If I wanted straight Mercon only I would end up probably having to get it at a Ford Dealership.
Also... what do you guys think about Lucas additives for the Transmission that "control heat" and "prevent wear" and things like that? Is there any truth to a transmission additive like that? Or would my E4OD be picky about that kind of stuff in the fluid as well?
Here is my e4od input. As stated above they are very picky on fluids. I do not agree with dual rated fluids, but to every person thier own. The e40d likes a good quality Mercon fluid. The best way I know of to tell is either shake the bottle of pour a little bit.
Wal-Marts Mercon fluid, is very thin, and the 2 vehicles i have seen it in, shifted hard. If you shake it its thin, and when you pour it out its not as red as some better fluids. I work at a Ford garage and use Motorcraft and my tranny shifts great with a pile of miles on it. When poured the fluid seems thinker with a LOT more red color. Napa or Valvoline is the same way, as are Pennzoil. Those are ones Ive used. So it doesnt matter what name is on the bottle, if its a good grade, it should be fine for that tranny.