Alright, I have had a Scangauge II since Christmas of last year. I have been monitoring the Transmission temps ever since. Highest I had seen was 155* going up a serious grade. I had been averaging around 135* and not much more for a while now. Would really have to push it hard for anything higher as well. Tom(mod) in the Excursion forum mentioned I should try to get it up to 165* to burn off moisture.

So here is where everything changes. On Wednesday I went out to a FTE meet and did a trans flush with Supertech MerconV and new Motorcraft filter. During the flush I ruined the cooler return line and patched it up for the drive home. I also noticed stacked coolers had been installed on my truck by a PO. With the new fluid I am averaging around 140*+. Temps never went above 150*.

On Friday I picked up a new cooler line from Horizonpartsguy.com and replaced it. After replacing the cooler line and adding more MerconV I went for a good drive and picked up a bed full of furniture. On the way back my scangauge got as high as 158*.

Is it possible the old fluid was deteriorated enough that it was too cool? Would MerconV change the temp range? Are stacked coolers ok for these trucks? I understand the temps are not bad or anything and I have checked the fluid while it is around 115* and running where the level is showing full. Should I worry about this stuff at all or just continue to monitor?

What temps do others with a 4R100 see on scangauge or other monitoring devices?

Pictures below, since everyone loves pictures.











Thanks for assistance.

 

A little more back story as well. When I purchased the truck less than 20k ago the transmission had a bit of harsh shifting. My brother assisted me with a pan fluid change, we used Oreilly Mercon/Dexron. Instantly felt better.

 

Firstly, I have to say, if that is your daughter, holy crap she's a cute little girl.

I know very little about the transmission temps, but this is something I would love to learn more about. I think I have learned what burnt transmission fluid smells like, but I have no idea what the safe operation range is, and even in my dad's F350 pulling a load I have had a hard time getting the stock gauge to move. On my excursion I've never seen it move from the midway point. I will plug my SCT tuner in and see what that temp is if it helps.

I don't know if this thread will help any, but this is one that I found while googling:

https://www.ford-trucks.com/forums/1...emp-4r100.html

 

Thanks DU.

Stock Gauge? These trucks or at least mine do not have a trans temp gauge factory. It is also my understanding that they move only when at a failure point.

Going through the link provided now.

 

Could it be overfilled?

Deteriorated fluid won't make it run cooler. Maybe hotter since it can't lube as well, so there will be more friction. But that would be a very small change.

No.

They are much better than fin & tube.

I would't worry for one second about those temperatures.

Anything below 220F is safe. You can go as high as 250F for no more than a half hour at a time.

The stock gauge will sit right in the middle any time the fluid is warmer than 50F and colder than 230F. So if you're anywhere in that 180 degree range the gauge won't budge.

 

I would say I average about the 135 you mention. I do not know when the fluid was changed and I purchased in September of 2014. I have only put about 6k on it and have not towed. It is next on my maintenance schedule before family trip to TX.

-Art

 

last time i looked at a bottle of SuperTech Mercon V it carried Ford's certification number, so there should be absolutely no issues with the fluid.

 

Mark- the fluid level at 112* idling on flat ground was a hair passed the hash marks and straight line. My Dad looked at it as well and we both thought it looked fine. My truck has the original cooler and another tube and fine tied onto the AC condenser as well. I may have been a little unclear about that. Looks like from the other thread Drunken Unicorn posted temps are right where they should be. 80-100 over ambient temp. Thanks for chiming in.

Meborder- I read the bottle as well, there is another Supertech that is recommended but that isn't certified. Supertech is also cheaper than every other fluid I have seen.

 

I see from your sig that your truck is a 99. My 2002 does have a "stock gauge" that measures trans temp.

 

Ah, didn't know.

 

80-100 over ambient is about right for me via Scanguage. Stock cooler and an early build without the rad cooler.

 

you should strongly consider removing the second auxiliary cooler (the tube and fin). adding a second auxiliary cooler can reduce the cooling capacity of the system due to reduced flow.

at a very minimum, do a flow test to make sure you are getting enough cooler flow
https://www.ford-trucks.com/forums/1...flow-test.html

you are correct. Supertech Mercon/Dexron3 is recommended by the fluid maker for use in vehicles that originally specified those fluids, but the Mercon V carries the ford certification, so there isn't much reason to use the Mercon fluid as the Mercon V has been specified to replace Mercon in all applications.

 

So you have three coolers. The radiator cooler, the stock air to oil cooler, and the tube & fin cooler.

I do not like tube & fin coolers. Their only reason for existing is that they are very cheap to make. And you get what you pay for. They have more flow resistance, but much less cooling capacity that a stacked plate cooler.

I also don't like three coolers. As mentioned above three coolers can have less cooling capacity than two coolers due to the increased restriction and less fluid flow.

 

I will have to get under and look but I don't think mine has the radiator cooler. When I was tracing the lines it didn't appear to go through it.

 

Before I had my trans rebuilt, I was seeing temps around 180 for daily driving and 200-220 for light towing. It wouldnt cool down, just keep building temp.

After the rebuild, DD is around 150-165 and towing, even heavy, 180. Warmest I've seen heavy was about 187. Heavy for my rig is 24' enclosed (insulated and diamond plate floor) and a complete '70 Boss 429 (heavy pig). I figure around 8-9000 lbs? Thats using the Banks tuner on "Tow/Haul" mode. I use OD for anything over 65 and cruising, usually click it off under 60 for passing or slow traffic. It seems to like 75 for straight line runs and about 50-55 in third gear.

Keep in mind, post rebuild there was a big 6.0L cooler installed as well.

This years trip (Poconos) may have a side bar to the weigh station.