What are these ranges based on? These number do not come from Ford. In fact, the Ford engineer who helped design the 4R100 has posted on this board and other boards that the design operating temps are more in the order of 220*-230*, with short periods of 240*-250* being OK.

And I have posted previously on this board and others that the design specs for MERCON (the recommended fluid for the 4R100) requires prolonged testing in the 250* range. And this is for a non-synthetic fluid (as the specs for MERCON are not so strenuous that synthetic base oils must be used).

So if you have some information from Ford verifying that the normal operating range of the 4R100 is 160*, I would very much appreciate a link. I have spent hours in the past looking for such a spec and have never found it.

What I have found is some old chart that no one knows the origin of, nor how old it is, being circulated by tranny shops, makers of tranny coolers and purveyors of synthetic tranny fluid that suggest temps in the 180*-190* range max.

 

The OP went out and tested his truck on the highway, unloaded, and reported temps of 160 degrees, that is where the number came from. I had similar numbers, actually lower in a 4r100 equipped F350. In neither case were we quoting factory book numbers, just real world experience. I love guys that live and die "by the book". Good luck with that.

It is extremely difficult to say where the temp numbers you quote came from. Are they on the hot side, going to the cooler, at the trans, are they pre cooler, post cooler, in the convertor, where did Ford take the temp measurements from? Did Fords numbers come from a 7-8 year old truck?

He is seeing a 50 degree rise, he could see more on his trip if it includes hills, traffic, and/or higher ambient temps. I PERSONALLY WOULD FIT A LARGER COOLER AND FEEL BETTER RUNNING LOWER NUMBERS. If you disagree, go ahead and run 230-240, it is your truck. Maybe you should quit busting my ***** and address the OP. Convince HIM that there is no issue. I wouldn't run it that way for long though.

You failed to address my question. Would the fluid and trans last longer if it were run at 180-190 or at the 220-230 you and Ford suggest is "normal"? Seems to me it is a pretty simple fact that higher heat will break down the fluid and additives more quickly.

 

Just making sure here, as we are comparing apples to oranges. So your numbers come from paranoia, not really any facts? So you see monsters under your bed at night and so should I?

There is a service interval for the tranny fluid. For a 2003 Expy/Navigator used for trailer towing, that interval is 30,000 miles.

So yes, MERCON will last for 30,000 miles at 220*-230*. Might it go 50,000 miles at 180*-190*? Maybe so. But as it is recommended at to be changed at 30,000 miles, does it really matter (unless, of course, you are deciding to ignore Ford's recommended service intervals too)?

All sorts of people post on these boards, and they all have differing opinions. The only way to sort through all of the opinions is to know the basis for the opinion. What facts, experiences, etc. helped to form the opinion. From that, the reader can decide for himself what to believe and what to ignore.

The point of my posts is to explain where my opinion came from and to examine more fully the basis of other people's opinions.

What you ultimately decide to do is up to you.

 

OK, but you once gain have chosen to ignore part of the argument. Where are the temperature readings you want to use taken from? The 4r100 doesn't come with a temp gauge. Trans temps can vary substantially depending on where the reading is taken.

So if we use your argument that 220-230 degrees is "normal" operating temp for the trans, and the poster is reading 160 degrees on his gauge during normal use, we have a discrepancy. If you then add the 50 degree rise he is seeing when towing to YOUR normal numbers, we are at 270-280 degrees, which is in the danger zone by any definition.

I purposely have my bed sitting on the floor to keep monsters from making homes under there. I also like to have a safety buffer when it comes to trans temps.

My experience comes from owning, and towing with many different trucks. I had a business that used light trucks towing heavy trailers to deliver products. I used a '99 F350, '01 Chev 2500HD, and two '03 Dodge 3500's all with auto trnasmissions. All hauled in excess of 15,000 lbs over rolling terrain in high heat and humidity for between 100,000 and 250,000 miles each. I have also personally owned half a dozen more 3/4 and 1 ton trucks for personal use, and all did a lot of heavy towing, over a lot of miles. I have only hurt one trans in an '03 Chev. It never even towed more than 7-8000 lbs, and I got rid of it at 35k miles. That one had a trans temp gauge, and was never overheated according to the gauge. My experience is real world.

From my F350 experience I know that finding a good place for the trans temp sensor is tricky, that is why I question where your numbers are measured from. When I used the reccomended port in the side of the trans to measure temps, I never saw temps over 210 when towing. That is towing twice what the OP is towing. I did add an additional cooler because it would overheat when plowing snow.

My experience suggests to me that if it is running 210, depending on where you take the reading from, it could very well be running too hot. Hence my suggestion to run a larger, or additional trans cooler. Be my guest, run yours warmer than that. The ~$100 it takes to fit a cooler is a small price to pay for additional trans cooling capacity. Transmissions never fail in the driveway, they fail on the road, usually on a very hot day with a big trailer behind. In that case the $100 cooler that helps you avoid that prospect just paid for itself several times over. Your milage may vary.

 

And I too have years of experience towing up to 11,000 lbs in 100* heat and in the mountains. Never any temp gauge other than the factory gauge. Never any trouble.

You are correct that placement of the temp sender is critical. As I did not do the testing, I do not know where Ford placed the sensor, but I can assume it was somewhere close to where the factory gauge sensor is located.

Your tranny temps while plowing are a completely different animal from when towing. Lots of shifting, high loads, no air through the cooler. Once again, apples to oranges.

As far as what temp I like to run, I have no idea. My truck has a factory installed gauge (my Dodge only had an idiot light). If and when the gauge goes to yellow (which none of my Fords have ever done), I will slow down. Until then, I do not worry about it.

Sorry, but I read many, many posts by armchair engineers who set their own standards, usually based on old wives' tales, and encourage others to totally ignore the decades and millions of miles of research and experience of the fluid manufacturers and OEM manufacturers.

Trust me, Ford has far more experience building and testing HD truck transmissions than you. When you ask me to trust you or Ford based on experience, you are a babe in the woods.

This topic has been vetted sufficiently for people to make up there own mind.

 

Interesting...Had I not installed an aux trans coolers on two different Fords I have owned, they would have fried their transmissions for sure. Glad you trust them...

 

Which mountains were you in where temp reached 100 degrees? I live and drive in the rocky mountains of Colorado, I don't recall 100 degree temps ever.

And the truck you are talking about has which transmission? Not the 4r100 correct? The 4r100 never had a factory gauge.

Seems like apples and oranges in your posts too Mr.Armchair engineer

Again, not on a 4r100 transmission. I ran Dodge Cummins trucks because Ford didn't offer a decent TD engine...seems they still do not. Never lost a trans in a Dodge, and I ran them in real mountains, with real loads. I have scale tickets that range from 24,700 to 30,500lbs. Trips I made through the rockies in summer.

Yet somehow, your advice is to be heeded over mine? Interesting, and based on what you have read, rather than what you have done. Funny how the road that runs through my town is one used by Ford engineers, as well as the Corvette guys, Porsche and Audi, as a high altitude testing place. I drive this road over 10,000 miles a year, and have for years.

Making Ford engineers out to be so infallible is rather humorous to me. The same guys that installed the 6.0 into trucks and almost bankrupted the company due to recalls and warranty claims???? Yep, you go ahead and trust them implicitly, good plan.

I would run and hide if I were you too.

 

fwiw my trans temp sensor is in the side port of the trans, on the driver side right above the #2 trans pan bolt.
I will be adding the cooler in the truck once I get back. It seems logical to me to bring the temps down a little bit, even if only 180-190 would be an improvement that I could live with.

It seems that trans temps are variable, and everyone has there own comfort zone at what temp their trans should be or what they want it to be. Mine is cooler temps, even though the truck maybe fine with hotter temps, I'd rather have cooler temps and be on the safe side myself. Now others may not think this way and heck most dont even have a clue what their trans temps are while towing, there arent many trans temp gauges flying off the shelves and the manuf. isnt putting them in either too often. So I think it is more of a personal preference thing at what you feel comfortable at and I asked because I felt them temps were a little too high for my comfort zone.

Now what cooler to put into it is the next question?

 

Well today I relocated the stock trans cooler on the Navigator. The engineers put the thing down below the grille. There is some air movement down there via the lower grille that is only about 4 inches wide, but I thought maybe that was part of the hot temps I have been getting.

I moved it up using the orignal bracket with a little bending, and put it directly behind the top grille.

I took it for a ride today and seen temps about 10 degrees cooler, I ran around town and got it up to about 150, and thats in ambient temps of 88-90 which is a little hotter than 85 like the other day when I took it out.. So 10 degree difference just by moving it made a small difference.

Tomorrow Im going to hook up the trailer and take it the same route I did when I was getting the 210 temps and see if it also drops for me. Im hoping/ thinking it will as it now has alot of airflow over the fins and isnt kind of blocked off at all like it was down below in the lower part of that area.

 

Ok so today I went and took a little ride in the truck and trailer. Now first I did mod the stock trans cooler. I moved it up behind the large part of the grille on the Navigator. I then also added a 12" pusher fan in front of the trans cooler.

The temps I seen today are cooler, they were at 205 degrees on the freeway with the trans cooling fan running. But also the temps here were 10 degrees hotter than when I did my first initial test a few days ago and was getting readings of 210 on the freeway.

Today I also seen the temps stay steady when I got back into the city they maybe went up a hair maybe 2-3 degrees the needle barely moved.

So in a nutshell I cooled down about 5 degrees on a 10 degree hotter day probably more because the ambient temps outside were 10 degrees hotter, and also seems to have steadied the temps whether in the city or on the freeway (I also run without the overdrive on). And now I have a cooling fan that I can turn on anytime to cool the trans a bit if it needs it in the city

What you think, would I have achieved 15 degrees cooler because of the fan mod. and moving the trans cooler?

 

I think the key to your modifications is that you now have consistancy. There wasn't anything wrong with 210 degree temps, just that traffic, hills, and changing ambient temps could have easily pushed the temps higher. Now you have some control over the trans temp. Sounds like a good set up to me.

 

Thanks BG. I think so too, it seems that I have better control now and can cool it faster if it needs it. Its not the best set up but will work for now.

I did this set up because I didnt have time to order and install the Trucool, I dont think that it would have arrived in time. So I seen that B&M sold a cooler that was smaller but had a fan. So off to the junkyard I went to get a $20.00 Mercedes pusher fan. I figure Mercedes made a good car so the Bosch fan should hold up for a while. And it sure does throw some air.

So now do I have a Hybrid, is my truck a Lincoln/Mercedes Navigator now?

 

Well the first trip with the new trans cooler fan went perfectly. In 93 degree outside temps, in rush hour with my 7500# trailer, through Detroit, the trans temp never got above 220 degrees.
Normal driving in that outside tmep range on the freeway (driving between 55-60 mph) the temps stayed about 200-205 degrees. I think I may just keep the set up I have until it fails me. It seems to keep the temps where I want them.

 

Having owned a half dozen Mercedes cars and trucks, I would say...no, not really close to MB engineering We have some pretty decent trucks but there really is no comparison. Adding a Bosch fan ain't gonna do it. Don't feel bad, I used Bilstien shocks in an attempt to get closer too, no dice here either.