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Discussion Starter · #1 · (Edited)
After every Transit I own breaking the transmission heat exchanger/cooler and destroying transmissions I've decided to remove that piece and use an adapter and Derale aluminum heatsink cooler instead.

I want low maintenance for my highway and off-road usage in hot weather. Death Valley was 124°f the other day!

I know our local Las Vegas Ford mechanic will chime in with how great the factory system is but I'm tired of driving ticking time bombs around.

On order is the Powerhouse Racing cooler line adapter and the Derale aluminum heatsink dual pass cooler unit to be mounted under the van(the big one).

No plans to use fans or front mount of the cooler unless warranted by the temperatures of the transmission.



Here we go. I'll have a local line builder arrange fittings and oil lines then do a fluid flush/fill followed by radiator/cooling system flush and fill and block off the lines that go to the transmission heat exchanger.

Bye bye hot engine and transmission temps!

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Discussion Starter · #3 ·
It looks cool, but I suspect a proper cooler (radiator style) will still be much more effective. What part of the factory system is failing? The connections or the cooler?
The heat exchanger fails and mixes coolant and tranny fluid.

It causes overheating of the engine and fluid loss in the transmission.

Every Transit I have owned, 5, have killed the transmission around 200 to 250k miles do to this parts failure.

You could just replace the heat exchanger but I'm tired of the piece failing and mixing fluids and then the transmission dies an unnecessary death.

There is already a transmission fluid heat bypass valve that opens at 180°f to the cooler/exchanger. The transmission will be able to warm up and then radiate the excess heat with the heatsink cooler. I got the largest model at 25" with internal and external fins. Based on how small the stock cooler is I think it will be more than enough.
 

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Discussion Starter · #6 ·
@Chillis would be interesting to know what your line builder specs for the tranny fluid lines. Flex or hard lines and fittings?
I don't plan on running long lines. Basically enough line to go from adapter to cooler nearby under the body with enough slack for engine/transmission twisting.

I thought the adapter said it came with AN8 fittings but that may be the rest of the adapters I saw.

The heatsink cooler says 3/8" NPT fittings so those will not be used and I'll try and match up some AN8 fittings for those as well.

I'll opt for the hardest soft line they offer and try to keep everything tucked out of harm's way.
 

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Discussion Starter · #7 ·
@Chillis Let me know how is goes.

I tried adding a standalone cooler on my 2022 3.5Eco with the 10r80, but i ran into an issue with the transmission connection.

My plan was to use the hose below, and a EVIL ENERGY 8 Pass Tube and Fin Transmission Cooler. I got the cooler and the line installed, but the plug is different on the 10r80, compared to the 6r80.

The plug on the 6r80 was Vertical (top/bottom) vs the 10r80 is Horizontal (right/left). I put mine back to stock, since you either have to cut the exchanger or drop the subframe to get the exchanger out. With out knowing if i could make it work, i didn't want to risk it.

On long drives with short stops(gas/food), i'm seeing temps from 210-220f (in 95F weather) on my ultra gauge when i restart the van. So this is still on my wish list to do.

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I hadn't checked the new design.

I can reach down and unbolt the heat exchanger from the radiator or just leave it there.

The lines are held in with 8mm retaining bolts.

The coolant line I'll just get a new piece to connect the radiator and the line off of the thermostat housing pipe. Or just cap the two ends off as the system is no longer necessary?
 

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Discussion Starter · #11 ·
The Derale 24" heatsink cooler is in.

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This will add a decent amount of transmission fluid. Also has the inner and outer fins.

The cooler adapter arrives tomorrow and I most likely will not be able to get the lines and fittings done until Tuesday.
 

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Discussion Starter · #12 ·
The Powerhouse Racing Low Profile Cooler Line Manifold has arrived although too late for me to get to the line shop.

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The factory hard/soft lines are pretty small internal diameter. I think I'll keep the lines I have built consistent with that.

Now, I'm debating whether to hide the unit underneath the van having very passive airflow or bolting it inside of the front bumper/brace?

If it is up front it will allow much more heat exchange but just being disconnected from the engine cooling system and how large it is should help considerably as well.
 

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Discussion Starter · #14 ·
Given the shape and fins, if you havent used the space between the fuel tank and side wall underneath, I’d put it there. Run it long ways with the van, so the air flow under the van runs the length of the fins.
If you mount it in the grill, only one side will be hit with fresh air and heat soak on the other.
After looking around underneath it seems like where you mention is the best place to keep it out of the way and passive. Not sure what type of airflows gets back there.

Also, in order to keep fluid level in the tranny consistent and easy to measure, it should probably be kept below the full line on the dipstick so it can't back fill into the pan during measurement when cold or possibly while hot?

The stock system is a very small amount of fluid in the tiny exchanger and small diameter hoses. That wouldn't effect the transmission as much as the extra quart or more with the new lines and big cooler.
 

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Discussion Starter · #17 ·
Given you're on the 6r80, and your love with replacing the transmission. Have you ever had them take out the thermal bypass value in the transmission, that doesn't open until it get to temp?

That value is why they have you wait until the transmission is at temp to check the levels.

As for the levels, as long as the cooler is below the adaptor/ports i'd keep it "full"
I saw the removal kit for the valve but I figure to leave it alone so the fluid temps rise quick and are not over cooled.

The fittings on the stock transmission lines are double o-ring so this system must be under low pressure. I'm wondering if the height of the cooler may be better served being higher like stock to help with drain back into the system.

Then again it is pumping up to the stock exchanger so it should be able to overcome high or low mounting.
 

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Discussion Starter · #18 ·
I don’t think those heat-sink coolers are intended for continuous heat rejection. Those are great for drag strips, and maybe autocross, where the heat load is short term. The “sink” part of it absorbs those spikes in temps, but releases the heat slowly. Aluminum isn’t actually that good of a heat conductor.
I don't believe the transmission needs a lot of cooling based on the stock arrangement.

This being disconnected from the cooling system drops temps immediately to whatever is ambient instead of what radiator temps are and the added volume plus heatsinking I'm guessing will be enough.

The stock cooler/exchanger doesn't provide any air to liquid thermal transfer. It is liquid to liquid(oil to coolant) with the coolant receiving the air to liquid thermal transfer.

I'm trying to isolate the systems so there is no transfer during exchanger failure as the stock system was fine before it fails.

Hope I'm right!

If not I'll just order a tube and fin style.
 

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Discussion Starter · #20 ·
I don’t think those heat-sink coolers are intended for continuous heat rejection. Those are great for drag strips, and maybe autocross, where the heat load is short term. The “sink” part of it absorbs those spikes in temps, but releases the heat slowly. Aluminum isn’t actually that good of a heat conductor.
Forgot to mention that I first learned of this cooler design from the off-road recovery rigs of southern Utah, Matt's Off-Road Recovery YouTube channel.

If it's good enough for their use on slow going 4wd in the sand and hills of UT pulling people out of the wilderness it should be alright here.

I know it isn't the most efficient cooler. Hopefully it doesn't need to be.
 

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Discussion Starter · #21 ·
Got back into town just in time to hit the line shop.

Still need fluids, radiator line/clamps, and brackets to hang the cooler.

The core pieces are in house though.

Got 180° snap on fittings to the cooler adapter:

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Then some of the same style of snap on oil line fittings for the cooler itself:

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I've never seen or heard of these but what I find attractive is that you can keep extra line and fluid and just cut off a faulty line and slip the new line on and fill.

Some high temp line to go with it which I'll trim to fit:

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I'll be using a bunch of 'L' bracket with holes in it to hang the cooler. Two long pieces to bolt the cooler to and then a piece on each end that is vertical bolted to the body spars and then some cut down 90's to connect the two assemblies together.

If that does not work I'll just get metal to drill and bolt up.
 

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Discussion Starter · #22 ·
Those stock cooler lines are a PITA to remove. Part of the lines are still attached to the engine where there is a bracket holding the hard lines.

I disconnected the lines from the exchanger and transmission. Then cut the soft section to remove the front half of the lines and then used a cutting wheel to cut the hard lines behind the engine line mounting bracket.

Installed the cooler adapter and started working on the angled bracket to mount the cooler and stopped there for today.

Tomorrow with fresh eyes and mind I'll finish hanging the cooler, fill and purge it, drain the transmission and fill it, then heat it up, manually shift all gears once up to temp and check fluid level.

The coolant lines are still connected to the heat exchanger. I'll leave those for the moment just to see what happens when the engine gets up to temperature, whether or not it starts passing coolant.

What I observed from pulling the lines is that the upper line(hot side?) Had brownish fluid and the other side draining from the transmission was proper red color. Fluid only had 30k miles since the full service.

The coolant in the reservoir turns purple when the transmission fluid passes through and mixes and I've seen this the last time I had the van out.

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As seen in the pics, angle bracket, I'll bolt the halves together and then use some more to hang off of the frame and try to tie it together for some rigidity.
 

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Discussion Starter · #23 ·
I got the cooler installed today, drained and filled a bunch of transmission fluid and ran it. Haven't gotten a hot fluid level check but before I ran it to purge air from the system/cooler it was maybe near the high side.

After running the van up the nearby mountain I can feel heat in the cooler and lines. Took running up a mountain to get the cooler hot enough.

I'm going to take it to a shop Friday to adjust the hot transmission fluid level and before then I'll flush out my cooling system and switch to the new yellow coolant.

I have a small obd plug in code reader. Need to see if it can tell me transmission temps or I'll hunt down that Bluetooth plug in.
 

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Discussion Starter · #24 · (Edited)
Edit to add that on the long hill climb my coolant never spiked and I was running both A/C units at maximum cruising up the mountain at 70mph.

Edit #2: with the heat exchanger failing and pushing out transmission fluid and pulling coolant into the transmission, when I popped the transmission plug to pull out the oil, the top half was a mix of tranny fluid and coolant. It poured out of the fill hole!

Poor transmission was high on fluid level and some being coolant.

After getting out more than a few quarts, maybe 5 in total with the lines, it shifts much smoother again.

As a side note, when the transmission was taking on the coolant my fuel economy went down and overheating was more frequent and then the transmission was skipping under boost.
 

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Discussion Starter · #26 ·
By those com
@Chillis
When i was looking for cooling options, i kept ending up on the mustang fourms, that were road racing them.
The one common thing i found was, they all said the sweet spot was keeping the transmission at ~175F vs the 190F or higher that the engine coolant keeps it at.

Better shifting and mpg, was the results for them at the 175F.
By those comments it sounds like I'd be better served with a fan assisted cooler to keep the temps more consistent.

First step will be proper transmission fluid level and then monitoring the temps under multiple multiple conditions.
 

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Discussion Starter · #29 ·
Your new setup with the 6r80, will be limited by the valve. If the cooler is good enough, it may make that valve open and close constantly. If the GM 6L80 has the same setting as yours, it opens at 70C/158F. (couldn't find a temp for the internal one)

The OEM setup is limited to the temp of the engine coolant. Which the thermostat for the engine is a ~190F.

So if the value is opening at 158F, you could be lowering temps 30F with just your passive system.

Since i couldn't remove the exchanger in my 10r80 setup to split the cooling, i've got a 170F engine thermostat to try out.
I've currently left my exchanger stuck to the radiator. The coolant lines still run through it although I'll monitor for leaks.

Not sure why you couldn't do the same and run an adapter and cooler.
 

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Discussion Starter · #31 ·
On my 2022/10r80, the exchanger is also the adaptor for the transmission. It sits right on the transmission above the sub frame. I bought the hard/soft line that comes on yours, with the adaptor built in.

But when i loosened the exchanger, i would have to either drop the sub frame or cut the pipes off the exchanger to get it out. Neither i felt comfortable doing, especially when the transmission ports didn't match the hose ports (hose ports are vertical, transmission ports are horizontal)
I wonder if that new design has had issues the way the old model has.

If you see the high temps I wouldn't hesitate to cut the stock lines out if the way and hang a fan controlled cooler.

I'm using seat bolts from my custom seats, installed longer ones, to hang the cooler.

The fuel tank strap bolts would be a great stock bolt option, longer bolts to make a bracket from.
 

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Discussion Starter · #32 ·
I'm going to need a proper flush and fill of this system.

I checked fluid level while cold and I was high, probably all the way to the fill hole.

Dropped some out of the system and I'm around the cold high line. I'm not sure if fluid from the cooler is backed up into the system though.

Cooler above transmission pan means the cooler will over fill the system on shut down.

The stuff I removed looked gross though. I don't have a way to check it hot without going and getting some high temp gloves. I'm going to go run it up the nearby mountain to see how it feels after removing some of the fluid.
 

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Discussion Starter · #33 ·
I took the van out and ran it up the mountain. Shifting is hit or miss. Not great. The van accelerates quicker and fuel economy readout is higher.

When I stopped to do a touch test on the cooler it was cool still. When I got back to the house just cruising it was warm.

No way to know fluid temps are at the moment so I did what any genius of the male species would do and grabbed the wife's cooking thermometer and touched it to the outside of the cooler. The temp got up to the 182f but was losing temp quickly as the van was shut down.

I can try and use the van tomorrow on a highway run and have the fluid flushed when I get to southern Utah and the level set while hot.

Or I can not use it and wait until Tuesday for a local place to replace the fluid/set level.

Cruising it feels fine and some shift feel fine. It randomly shifts poorly/notchy and sometimes has a skip.

It really liked the new fluid on the first run but I believe it has already been mixed into the crud that has been in there.

My OBD code reader doesn't offer any temp gauges, just emissions parts checking.
 
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