I have a 2004 National Seabreeze motorhome on an F53 Chassis with the V10 and 4100R transmission.

I think that I have ruined the fluid by getting it hot while making a few climbs coming out of Nevada into Arizona. I made it home without incident after another 1000 miles but I would like to change the fluid anyway. It got to point to where it would barely go above about 30 and would not downshift at all during the climb. Fluid temp got to about 230 according to the OBD2 via the Torque app on my tablet.

I have been reading up on this. How to, what fluid to use, etc. and have come across much conflicting information on the internet and none of which I trust. I have Mark's write up on the How To saved from Ford-truck.com but then I read another article on the type of fluid and that seems to conflict, unless I am an idiot and reading it wrong......which is highly likely.

Mark wrote this:

Transmission fluid - F150online Forums

1-30-2003
Ford does not use a full synthetic in any automatic transmission.

The factory fill MERCON fluid is a conventional fluid. The factory fill MERCON V is a synthetic blend.

In the driver's door jamb is a blue tag. One column will have a TR at the top. Below that is either a U or an E. If it's a U the transmission is a 4R70W. If it is an E it's a 4R100.

the 4R70W requires MERCON V fluid. The 4R100 requires MERCON. Bad things could happen if you use the wrong fluid.


And this from the how to write up that Mark wrote:

Changing ATF Fluid in a E4OD and 4R100 transmission - Ford-Trucks.com

By Mark Kovalsky

I’ve done this alone. It’s easier with a second person, and sometimes helps prevent spills.
1. Things you need to get started:
a. The E4OD and 4R100 transmission system holds almost 18 quarts of ATF, and you must waste a couple of quarts to be sure you get it all purged and replaced, so buy 20 quarts of MERCON ATF [For the 4R100, use MERCON V]. You may use either conventional or synthetic, as long as it meets the above requirements.

The bolded text from both past posts seem to conflict.

I want to migrate to a full synthetic to help with cooling and less breakdown because where I live, long climbs are normal.

i have been debating the Mobil 1
https://www.amazon.com/Mobil-112980-...rds=mobil++atf

or

the Redline.

https://www.amazon.com/Red-Line-3050...ct_top?ie=UTF8

Just want to make sure I am looking at the correct fluid before i waste a good chunk of cash to ruin my transmission with the incorrect fluid. Hopefully mark will see this and set me straight

 

@Mark Kovalsky

 

I first wrote that procedure sometime in the early 2000s. At that time MERCON was the correct fluid for the 4R100. In 2006 Ford discontinued MERCON and changed MERCON V to be compatible with older transmissions that used MERCON.

MERCON V is now the correct fluid for a 4R100.

And while you should change your fluid, 230F won't hurt the fluid. It can go a lot hotter than that before it is damaged.

Either Mobil 1 or Redline are excellent choices. I've used Mobil 1 many times, and I've heard good things about Redline, though I've never used it.

 

Thanks for the quick reply Mark. That is the sometimes issue with searching on the internet is that you find outdated information.

I will go with the Mobil 1 since its cheaper and easier to find.

Thanks again

 

Mobil 1 is my go to fluid.

When I was at Ford we supplied transmissions to an off road race team. We won the Baja 1000 several times, along with many other races, and several championships. Over the years we went from E4OD to 4R100 to 5R110. With the E4OD and 4R100 we ran Mobil 1.

One race (with a 4R100 in the truck) the cooling fans for the trans coolers failed. The coolers were in the truck bed right behind the cab. They were there to protect them from debris getting kicked up. Without the fans they had almost zero airflow.

We were in the lead, but not by a lot. The trans temp gauge was pegged at 320F for hundreds of miles. If we stopped to change the fans we'd be far down the standings with no chance to recover. So the decision was made to keep going and hope for the best.

We won the race. The truck had no further problems, just the pegged temperature gauge. After every race we would get the trans back and tear it down. We were not only supporting the race team, we were testing prototype parts. This was a high performance durability test for us.

The Mobil 1 was dark, and a bit smelly. It wasn't black goo by any means. The teadown showed the normal wear we'd see after a race, but no damage. Except to all of the solenoids. The solder had melted off the solenoids and was laying in the bottom of the pan!

We don't know how hot that trans got. But we do know that the melting point of solder is 450F. So we know the trans was hotter than 450F AND IT LIVED!

So when people tell me they damaged their trans because it got to 200F, or 230F, or even 250F, I know they are wrong. And that Mobil 1 is a superior fluid!

 

Mark
If the solder melted off the solenoids how did the transmission continue to operate ?

 

Liquid solder will "wick" to the parts, and even without that, the wires are wrapped around the terminals pretty tight when they are manufactured.

Great story, BTW

 

One more question to the brains

I think that i need to upgrade my cooler. I routinely make a huge climb that bogs me down to 30-35 mph for about 10 miles and often in 95+ temps. This obviously doesnt allow good airflow to the cooler.

I was looking at the 6.0 cooler which is much larger than my 9 row, tiny little guy.

Its pricey however. Which led me to come across this one. Any thoughts on this cooler or should I just hold out for the Ford 6.0?

https://www.amazon.com/Tru-Cool-LPD4...5711746&sr=8-1

I am going to look into getting a fan from a donor taurus from a wrecking yard. I am in the Toyota 4x4 world and many of us us those and they work outstanding.

The larger cooler and the fan for slow motion climbs should help manage temps better

 

Putting a fan on your existing one would help a lot - but then, 30MPH is a pretty stiff wind. What temps does the tranny get to now?

If it were me, I'd go for "stock" bolt on style. But it all depends on your skills, and it sounds like you have enough of those

 

rockauto has a Dorman brand cooler for the 6.0 for $165.

 

it will get up to 225 usually. sometimes higher.

A few weeks ago it got to the point that it would barely even still keep moving. About 20-25 was my max and i would not downshift. I pulled over and let it idle in N for a bit and then was good to go. I forgot my tablet this trip. It was 106 outside

i have read that the Dorman coolers are not as efficient as the Ford ones. Don't know if this is true.

 

Because the wires were wrapped around the terminals before they were soldered. They didn't fall off.

 

Great story, Mark. Thanks for sharing.

 

Thank you for the info, looking to replace my trans fluid in the truck I got from my Dad and he said he has been putting in MERC V and I was worried after looking at the specs calling for MERCON. So if MERC V can now be used, do I use that anywhere the user manual calls for MERCON, such as power steering pump and transfer case?

 

Thank you for the info, looking to replace my trans fluid in the truck I got from my Dad and he said he has been putting in MERC V and I was worried after looking at the specs calling for MERCON. So if MERC V can now be used, do I use that anywhere the user manual calls for MERCON, such as power steering pump and transfer case?