transmission cooler lines

jreaper7 · **Posted:** Sun Jun 14, 2020 2:17 pm

when facing the front of the vehicle, which hose going into the cooler is the supply line? left or right?

I'm replacing the cooler with aftermarket, I want the inlet coming into the top and out on the bottom. it will have to be mounted horizontally... that's why I'm asking...

https://www.summitracing.com/parts/hda-689

using this cooler, I will be towing with it.

thanks.

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WWDiesel · **Posted:** Sun Jun 14, 2020 2:40 pm

jreaper7 wrote:

when facing the front of the vehicle, which hose going into the cooler is the supply line? left or right?
I'm replacing the cooler with aftermarket, I want the inlet coming into the top and out on the bottom.
https://www.summitracing.com/parts/hda-689
using this cooler, as I will be towing with it.
thanks.

Simple, using the diagram below, trace the upper metal cooing line coming from the transmission to the front to the OEM transmission cooler.
The top line is to the cooler.
or
you can disconnect the hoses going to the OEM cooler, aim them into separate containers, crank the engine over for a ONLY a couple of seconds and you will know which one is the pressure line real quick. :lol:

Be sure and top off the transmission with some AFT+4 after installing the new cooler. It is advisable to slightly overfill the transmission by a half a quart or more.
These are big transmissions and are most happy when slightly overfilled.

jreaper7 · **Posted:** Sun Jun 14, 2020 2:41 pm

awesome! thank you for your help!

that's exactly what I wanted to know.

also, I appreciate the little tip on the atf. that is great info.

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jreaper7 · **Posted:** Sun Jun 14, 2020 7:22 pm

no more leaky leak!

thanks for your help wwdiesel!

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WWDiesel · **Posted:** Sun Jun 14, 2020 11:42 pm

Looks real good! :rockon:

That's a stacked plate oil cooler, they are real efficient, much more so than the regular tube and fin type.
Do you have a transmission temperature gauge or a way to monitor to see how much difference the new cooler makes?

jreaper7 · **Posted:** Mon Jun 15, 2020 3:18 am

I do not, unfortunately...

maybe down the road I'll install one.

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Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

What made you think that it needed extra cooling?

jreaper7 · **Posted:** Mon Jun 15, 2020 2:28 pm

Jett wrote:

What made you think that it needed extra cooling?

a: the cooler was leaking very badly.

b: it will be passively cooled, the more surface area to dissipate heat, the better

c: this was readily available at my auto parts store... the cooler was leaking about a quart a month. I had to get it replaced asap.

d: I will be towing with it, I don't want my transmission to overheat towing a trailer across the us. this is overkill, but better than getting one too small and it being inefficient.

e: aftermarket coolers are meant to be used in conjunction with the oem cooler as a supplemental cooling source. I had to bypass the oem cooler because of the terrible leak. I know I'll never overload this cooler. at least it's peace of mind.

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Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

Cool. (Pun) just asking because I’m in the same boat. Want bulletproof tranny and also want to tow heavy up mountains and stuff. But I’ve read that these diesel equipped rigs already have a more robust cooling system than the gas rigs and as such don’t need extra cooling, but while you were in there it makes a ton of sense. Mine is leaking too but not that bad yet. So I may do the same. However that type of cooler is pretty expensive and that is a huge one, so it will provide a lot of cooling for sure, and my only concern is that it might rob a little airflow from the other coolers. Let us know how it works towing uphill

jreaper7 · **Posted:** Mon Jun 15, 2020 2:37 pm

Jett wrote:

Cool. (Pun) just asking because I’m in the same boat. Want bulletproof tranny and also want to tow heavy up mountains and stuff. But I’ve read that these diesel equipped rigs already have a more robust cooling system than the gas rigs and as such don’t need extra cooling, but while you were in there it makes a ton of sense. Mine is leaking too but not that bad yet. So I may do the same. However that type of cooler is pretty expensive and that is a huge one, so it will provide a lot of cooling for sure, and my only concern is that it might rob a little airflow from the other coolers. Let us know how it works towing uphill

it's off to the side, and there's about a 2 1/2" gap between the cooler and the heat exchanger / a/c condenser. it doesn't obstruct flow at all to the other units.

I had to modify the front, as you can see. but it is doing the job very well!

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Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

Why did you go in the toP and out the bottom? Doesn’t that trap air in the cooler? I’d assumed you would go in the bottom, out the top.

jreaper7 · **Posted:** Mon Jun 15, 2020 4:12 pm

Jett wrote:

Why did you go in the toP and out the bottom? Doesn’t that trap air in the cooler? I’d assumed you would go in the bottom, out the top.

it would trap air in the cooler if you did it that way, from the top it will saturate the cooler, preventing air from being trapped.

also, if your went through the bottom, the pump has to then push the fluid up, through the cooler and then back into the transmission, from the top it doesn't have to work as hard... with a radiator you can "burp" the system. the transmission is a closed system. not many ways other than taking the dipstick out to release air pockets, and if it's stuck in the cooler, no really way to get it out.

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Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

Hmm, I dunno on that. I think you’ve got it backward. Also, raising fluid, it’s the same either direction. I think you want to fill from the bottom so air leaves immediately and you’re left with solid fluid

jreaper7 · **Posted:** Mon Jun 15, 2020 5:37 pm

Jett wrote:

Hmm, I dunno on that. I think you’ve got it backward. Also, raising fluid, it’s the same either direction. I think you want to fill from the bottom so air leaves immediately and you’re left with solid fluid

why would you want to fight gravity with hydraulic pressure?

I've been working on cars for awhile now. filling from the bottom in a radiator makes sense as air will rise to the top of the radiator. with the system unpressurized, they will dissipate. that's how everyone without a pressurized equipment replaces radiators...

you don't want air trapped in a closed system like a transmission... especially a cooler...

from the top, the fluid flows down, I don't get the reasoning behind wanting fluid to rise to the top in such an instance. that's not a principle of fluid dynamics. pumping fluid up will cause air pockets. not the other way around. either way I don't have air and it works. so there's that.

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WWDiesel · **Posted:** Mon Jun 15, 2020 10:56 pm

Every coolant system I have ever seen, the thermostat discharges into the top of the heat exchanger (radiator) and the pump takes it's suction from the bottom of the cooler, even on cross flow units.
Same principle applies.....

jreaper7 · **Posted:** Mon Jun 15, 2020 11:03 pm

WWDiesel wrote:

Every coolant system I have ever seen, the thermostat discharges into the top of the heat exchanger (radiator) and the pump takes it's suction from the bottom of the cooler, even on cross flow units.
Same principle applies.....

some state their radiators flow from the bottom up... I won't argue that point as I haven't worked on every car out there... but I have worked with hydraulics most of my career. I've never personally witnessed a scenario where you want an inlet to be at the bottom of a heat exchanger.

this question has been asked of me numerous times, I don't understand where it comes from...

regardless I respect your input fully, wwdiesel. thank you for your response.

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transmission cooler lines

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