How to properly plumb your 5EAT transmission cooler

[ken2116]

Recommend you confirm your own lines. Those on our 2006 Outback LL Bean (H6, 5EAT) are plumbed the opposite of the original poster's diagrams - the ATF exits from the cooler hose at the passenger's side. It's easy to tell, after removing the lower engine cover remove the atf line you think is the return line (suggest separating the rubber tube from the cooler where it connects to the metal pipe) and run 3/8in. I.D. vinyl tubing from each line (use a barbed coupler for the hose to hose connection) to empty milk jugs or similar and and have someone start the engine while you watch for which line flows. Be sure to replace what you lost.

 

If it's time to change the ATF, this is a good time as you have the hoses hooked up for pumping out as you simultaneously refill at the dipstick tube, stopping when the clean fluid flows out - our's took about 12 qts. as there is some mixing - this was after draining and refilling the pan to recuce mixing.

[richierozay]

Got a rapid cool for 05 lgt 5eat and I went with a thermostatic sandwich plate. Any1 have any experience with those? I'm still tryna figure out how to route it all

 

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[AW4BYT]

Aloha Climber. Quick question when routing the thermostat one would eliminate all connections at the hard lines correct? Or at least that’s what I understand looking at your “best” diagram.

[VdubaRoo]

Recommend you confirm your own lines. Those on our 2006 Outback LL Bean (H6, 5EAT) are plumbed the opposite of the original poster's diagrams - the ATF exits from the cooler hose at the passenger's side. It's easy to tell, after removing the lower engine cover remove the atf line you think is the return line (suggest separating the rubber tube from the cooler where it connects to the metal pipe) and run 3/8in. I.D. vinyl tubing from each line (use a barbed coupler for the hose to hose connection) to empty milk jugs or similar and and have someone start the engine while you watch for which line flows. Be sure to replace what you lost.

 

If it's time to change the ATF, this is a good time as you have the hoses hooked up for pumping out as you simultaneously refill at the dipstick tube, stopping when the clean fluid flows out - our's took about 12 qts. as there is some mixing - this was after draining and refilling the pan to recuce mixing.

I'm glad this post was added because I just replaced my radiator, along with all the ATF oil cooler hoses. The flow chart I found showed ATF fluid exiting the tranny from the rubber hose furthest to the rear of the car, on the tranny, and following the hard line to the front of the vehicle. The longer molded hose routes across the vehicle to the passenger side still "hot". This was the routing my 09 legacy 3.0r had prior to removal. AS A SIDE NOTE: all my hoses are OEM and the end of the long hose(passenger side) where it connects to the radiator has a RED marking on the end of the hose. Most of the OEM rubber cooling hoses have color markings, sometimes along with an arrow or letter. They can still be FUBAR'd really easily (the heater hoses... Top hose from firewall connects to the lower port on the engine block). 100% mark your hoses prior to removal... I think paint pens are easiest. I find I start to forget things the longer I work on a car on a nice hot day. I have seen the flow chart to and from radiator shown both ways online. Apparently the Tribeca flow IS the opposite on the front side (radiator and external ATF filter). Anyone with stock PLEASE HELP with hose plumbing on the external mount. I have it entering the lower port and exiting the upper port. I found that direction on a factory schematic, and not sure if it's universal, 4eat,5eat, not generation or model specific.

 

Here was the original radiator BTW. That was the trash on the backside of the condenser, front side of radiator with upper and lower packing intact. It was still maintaining temp on the short drives I still made before the fix. I think it is a total waste of money to modify any of your engine cooling if the engine is stock. All aluminum double radiators, modified engine oil coolers, and ATF coolers or different temp thermostats. Only makes sense pushing more power and track conditions. Maybe I'm wrong...

 

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Edited June 6, 2020 by VdubaRoo

[VdubaRoo]

I jus did the rubber inlet, outlet hose from the ATF to the metal hardline that leads to the radiator and remote spin on. The OP even has the orientation of the hot pressure side metal line from the 5eat ATF and non pressurized cold return inlet feed backwards. A pic from the factory service manual confirmed that. The pumped outlet ATF hard line has a hex head bolt where it meets the ATF housing. I also believe the pump side outlet hard line is always the lowest external metal line. The metal return line is higher and the charge port (the metal line for the dipstick} is parallel directly besides it. But because the cold/hot and orientation of flow was opposite from the start, it would follow the correct path. But if you take 5 minutes and disconnect the hose line from the radiator, you will either have a flow out of the rubber hose or it flowing out of the radiator and all over the bottom of the car and ground. I don't think there is any suction for the return side, it's the ATF oil pump pressure. My point of this whole rant. The metal ATF outlet line is the left (or closest to the front of the vehicle} and inlet pipe is directly to the right of it. The entire system is supposed to operate between 153-176 F I believe. So I would be very careful about a different cooling set up. It seems the 5eat has a lot of electronics that rely on correct temp range for it to function properly. I thought fluid flow and pressure are what makes an auto tranny work. The tranny adapts electronically somewhat, so it could be very hard to notice that it's not happy. JMO.

 

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[hallowground]

I have a BM supercooler 70264 that has a bypass built into it. Would it just be easier and better to just go from radiator to cooler to 5eat or should i pipe it like you recommended? Also i have a 2011 3.6r with 5eat and i was curious as to what filter is on these diagrams?

 

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[VdubaRoo]

You want your aftermarket cooler post radiator. It sounds like you mean a thermostatic bypass valve on the cooler since a pressure bypass doesn't make any sense. This thread has had me question the factory set up of direction from the transmission and return. Find the factory service manual for your vehicle. Thermostatic cooler bypass only makes sense post factory flow from the radiator. I'm not even sure you can monitor ATF temperature via the ECM. Radiator coolant temp stays between 195f and 203f. Cooler isn't better in the engine and the transmission will not shift to s# until it warms up to a point. Too cold isn't good and too hot isn't either. Hope it works out.

 

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[Danrc28]

 

Nice. This is the same setup that I just talked about on the phone with a person in Colorado, who still had to block the whole 4454 during the coldest winter months, even with the bypass thermostat. Just a heads up for you to keep an eye on.

 

I understand that the Tru-cool LPD coolers have a cold weather passive bypass already built in (https://trucool.com/products) just wondering at that point if the Derale Fluid control thermostat really adds any benefit? Spoke to a supplier and he mentioned that people like those coolers because it saves them the cost/time of having to setup a bypass.

 

If there is a benefit I still think I will get one (I’m in Vancouver, BC, and winter temps usually can get around 32F, lowest I’ve seen it hit here is around 14F but that’s not very often. Also thinking the 4454 is a good size for towing 3000lbs with my 2013 OB 3.6R through the mountains here, just scratching my head on that bypass.