Transmission with built in thermal bypass (6R80)

[JimmyM]

I have a 2011 Ford Expedition with the 6R80 transmission.
It has the HD Towing option, so it has an aux transmission cooler from the factory (22" wide, 4 rows).
The 6R80 has an internal thermal bypass so fluid doesn't even go through the cooler until it hits 175F-ish (I've read varying numbers).
But the fluid is plumbed from the trans to the radiator then to the aux cooler and back to the trans.

So my question is... If the fluid doesn't leave the transmission until it's over 170F, why does it go to the radiator at all? It's already warmed up by the time it gets there.

Shouldn't I be able to route around the radiator heat exchanger and directly to my new filter and 13-row cooler (Excursion V-10)

 

[tcp71]

It's less about warming up the fluid than cooling it. The coolant around the Radiator cooling loop is often lower than the engine coolant temperature and scrubs some initial heat out of the transmission fluid before hitting the oil-to-air cooler. Transferring heat to the coolant allows the fans to scrub some the heat away if there is little airflow...think towing up a long uphill on a hot day and having to stop dead (accident or other traffic jam). The effectiveness of the fans is better on the radiator than the aux cooler out front. The non-tow equipped trucks don't have the aux cooler but always have the radiator loop. The 5 liter engines have a separate fluid warmer. I would leave it in the loop. From the 2016 cooling guide:

 

[tcp71]

I added a filter system to my 09 F150, but didn't feel the need to add additional cooling.

 

[Purpfox]

Id like to lower the temps myself. Kinda hate the grill arrangement on the 15 up f150s. Makes it tricky to find suitable remote filter locations.

what year v10 expedition did you use for the part number

 

[JimmyM]

WOW. Thanks for the fluid diagrams! I see what you mean about a little initial cooling and the advantage of the fans. The hottest I've seen the transmission was 212F on a, you guessed it, slow uphill pull. Plenty of converter slip I'm guessing. I'll leave the routing as is. But will be adding a larger cooler and filter.

There are 2 bigger coolers for the Expeditions. Both fit the factory locations.
The 2000 EXCURSION V-10 (13 rows, different port config). It takes a little modding to cut the factory mounting brakets off. If you search for Dorman 918-276 you can find how-tos.
The "Problem" is sourcing the 5/8-18 Inverted flare to 1/2 hose barb fittings. Gates G36500-0806

Then there's also the F-150 "Saudi Arabia" cooler (9-rows, Ford#DL3V-7A095-B)

 

[MolaKule]

Originally Posted by tcp71
I added a filter system to my 09 F150, but didn't feel the need to add additional cooling.




That's quite a surface area for that filter so I can see why no additional cooling apparatus would be necessary.

 

[JimmyM]

I need to get the front of that thing apart to figure out where I'm going to mount my filter. Although tcp71's is looking pretty good.
I've got some work to do when the weather get's warmer.
The 9-row cooler is not quite the monster that the 13-row is, but it's more than double what's there and is literally a drop with the ports is the same locations and everything.

9-row cooler on Tasca

 

[tcp71]

That picture is of my 2009. I ended up using a magnefine on my 2016 because there isn't enough room for the full remote setup with the grill shutters in the way. I pulled the hose (circled in the picture) that runs along the top of the cooler and replaced it with the magnefine and two pieces of 1/2" hose. The magnefine is clamped to the center mount (arrow in the picture) where the hose was attached.


Originally Posted by Purpfox
Id like to lower the temps myself. Kinda hate the grill arrangement on the 15 up f150s. Makes it tricky to find suitable remote filter locations.

what year v10 expedition did you use for the part number

 

[JimmyM]

My 2011 Expedition is more like your 2009 F-150, so I think my filter (probably an XG16) will fit right where yours is. It being behind the grill will make changing it a pain. But then again. I probably won't ever need to change it.
I'll be doing a trans pan with a drain plug & magnets, new internal screen/filter, the external filter and larger cooler when I do my remote engine oil filter. Hopefully in the March/April time frame.

 

[MNgopher]

I'm curious if all the effort is worth it. OP reported the highest temp he's seen out of the transmission as is is 212F. Normal operating temp on these transmissions is 195-205 depending on the setup. (I own two of these transmissions - a 6R60 in an Explorer and 6R80 in my F150) and under the scenario described, the temps are perfectly reasonable. Highest I've ever seen out of mine is 210 degrees, with one pulling a boat at low speed for a time and the other driving in the high rockies in high temps...

I get it, extra capacity is generally always welcome (unless its arctic cold like now here, but that's what the thermostat and heat exchangers are for...).

 

[Purpfox]

With plans for an upgraded stall converter, the added cooling will be beneficial.

 

[JimmyM]

I suppose a lot of what's discussed here could be looked at as "is it really worth it". Technically speaking. It probably isn't necessary. The "worth" part comes down to a few "costs". First, money. Sure. But I'll be in $200-250 in parts. Time, I like a good project. So that's fun. Then the risk of introducing some unexpected weakness. These are pretty straight forward mods.
But with my "summer of towing" coming up, I'll be more confident that hills or traffic jams won't give me pause with the truck loaded down with a 6500lb travel trailer, 5 people and all our stuff.
I missed who's planning on a higher stall converter.

A lot of stuff in the last month has progressed with a "While I'm at it" mentality.

 

[tcp71]

I had my 2016 up to 235F for both coolant and TFT going north out of Pemberton, BC on Hwy 99. Long steep climb with lots of switchbacks and low speeds. That was with the smaller trailer. The new one is 10 ft longer and 2500lbs heavier.

 

[JimmyM]

Yeah, wow. 235F I know modern transmissions can tolerate higher temperatures than old ones, but that would have made me cringe.
Oddly enough your trans will probably go another 300k without a hiccup.

 

[tcp71]

The coolant and transmission temp needle didn't budge at 235. I think they move to 3/4 position at 240 (245?) and the ECM starts cutting fuel/cylinders at 255 so I was still quite a bit below that.

 

[JimmyM]

Still though. That's way hotter than I'd ever want to see my transmission. How do you monitor your transmission temperatures if the needle is not a real needle and more like an idiot-light?

 

[hatt]

Originally Posted by JimmyM
Still though. That's way hotter than I'd ever want to see my transmission. How do you monitor your transmission temperatures if the needle is not a real needle and more like an idiot-light?

On my 2013 you can get an actual trans temp through the dash display.

 

[JimmyM]

Originally Posted by hatt

On my 2013 you can get an actual trans temp through the dash display.

On my 2011 Expedition I can't get it from the dash. I use TorquePro and an OBDII adapter.

 

[Linctex]

Originally Posted by MolaKule
Originally Posted by tcp71
I added a filter system to my 09 F150, but didn't feel the need to add additional cooling.


That's quite a surface area for that filter so I can see why no additional cooling apparatus would be necessary.

My external trans filter is a Baldwin BT839-10, about the same size as that Donaldson.

The surface area is a lot smaller than any finned cooler.... so I really didn't think of it adding much cooling capacity???

 

[JimmyM]

Originally Posted by Linctex
Originally Posted by MolaKule
Originally Posted by tcp71
I added a filter system to my 09 F150, but didn't feel the need to add additional cooling.


That's quite a surface area for that filter so I can see why no additional cooling apparatus would be necessary.

My external trans filter is a Baldwin BT839-10, about the same size as that Donaldson.

The surface area is a lot smaller than any finned cooler.... so I really didn't think of it adding much cooling capacity???

Why did you choose the BT839-10?