TRANSMISSION Oil Cooler Retrofit

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trailblazer

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There’s nothing wrong with the Trucool. I like mine with the cold weather thermostatic valve.
 

CaptainAmerica1

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I got my kit from glens auto performance. Trucool 40k, bracket, premade lines, hose spacers. Took me all of 90 mins to remove and install everything.
 

Geotrash

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Towed the 6500 lb alpha wolf camper out to Gauley Bridge, WV to do some camping, and was excited to see how the new radiator would do on some of those mountain grades. Had some really long pulls up 6-8% grades in 77° ambient temps for a few miles and she stayed below 220° for all but one of them. It was a stretch on I-64 that was a good 8% for a really long pull. Had to drop down into 3rd a couple of times to keep above 45 mph, and the temp crept up to 240° for only 30 seconds or so before she started coming back down and held 230° until we got to the top. Transmission never got above 185°. I can live with that.


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2007YukonXL

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>If you decide on the OE route:

1 Transmission Oil Cooler 20880895
1 Inlet Pipe 25999420
1 Outlet Pipe 15779543
1 Retainer 15049288

Can someone PLEASE zap over a picture of how this looks both from the grille side and the engine compartment side?

I received the above parts except the oil cooler itself and I have the radiator out and I am trying to figure out the pipes...without the oil cooler in hand it is difficult to visualize how the pipes interact with each other.

I might have received the wrong pipe...The "Inlet Pipe 25999420" is that a two pipe/hose assembly as shown in this picture...I ask because I received a pipe with rubber hose that is a single assembly and I cannot visualize what end goes where.

https://www.gmpartscenter.net/oem-parts/gm-inlet-pipe-25999420?origin=pla&msclkid=39e2ab88b1111c3f8076cbfe9f8cf07a&utm_source=bing&utm_medium=cpc&utm_campaign=Shopping - All .05 Nickle Bid&utm_term=4584001428987132&utm_content=All

I might have gotten the wrong part. The pipe assembly I received is GM 25999416 and it looks like this and the internet shows that the pipe is #2 in the attached diagram:

https://www.gmpartscenter.net/oem-parts/gm-inlet-pipe-25999416




THANKS!!!

View attachment 276290
 
Last edited:
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2007YukonXL

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I found this video and it is helpful...I think the answer is that I got the wrong pipe assembly

 

bigdog9191999

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My 2007 GMC Yukon does not have an external TRANSMISSION oil cooler as it only has the radiator tranny oil cooler fittings.

Has anyone installed an external transmission oil cooler? T

Is there a kit available with the oil cooler that mounts in front of the radiator and lines pre-made I might go that route.

Any suggestions, advice, pictures, or well wishing would be appreciated!!!

THANKS


I would purchase this bracket: https://atomicfabandperformance.com/product/trucool-40k-trans-cooler-mount/

Also, there engine mounts are superior!![/QUOTE]


I have always just cut the line on the exit side of the factory cooler then to the aux cooler. so your order of flow would be trans, factory cooler, aux cooler, trans. a piece of hose with a worm clamp or two ( either cutting the stock hard line and clamping to it or cutting the factory hose and using a short piece of pipe to attach the two hoses).

in this configuration the rad cooler will warm it in the cold temps, and when working it works as factory to cool it some, then the aux cooler brings it down further before sending back to trans.
 
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2007YukonXL

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I have always just cut the line on the exit side of the factory cooler then to the aux cooler. so your order of flow would be trans, factory cooler, aux cooler, trans. a piece of hose with a worm clamp or two ( either cutting the stock hard line and clamping to it or cutting the factory hose and using a short piece of pipe to attach the two hoses).

in this configuration the rad cooler will warm it in the cold temps, and when working it works as factory to cool it some, then the aux cooler brings it down further before sending back to trans.

Wow I am surprised at how much this "simple" project is kicking my assets...

The pipe connections to the transmission are NOT the one bolt with an aluminum block that holds both tubes into the transmission...they are two separate tubes with the "horseshoe clip" and it does not look like I would be able to get in there to unclip it without (like someone posted) taking the exhaust system down.

So I am now going to cut the existing return line and use high pressure fluid rubber to splice between the existing return line and the remote cooler.

THE QUESTION IS...What is the transmission return line...the top or the bottom?
 

Foggy

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Bottom line at transmission is the return(cool line) Top line at trans is the HOT
fluid going out to the transmission cooler/radiator- on a 6L80E Trans
I just got done removing my oem aux cooler and installing a fan forced derale
trans cooler. I mounted it behind the bumper area since it doesn't need direct flow.

It was a PITA too... seemed like it would be simple, but I am ocd . Still need to test
it out under towing conditions
 
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Bill 1960

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>If you decide on the OE route:

1 Transmission Oil Cooler 20880895
1 Inlet Pipe 25999420
1 Outlet Pipe 15779543
1 Retainer 15049288

Can someone PLEASE zap over a picture of how this looks both from the grille side and the engine compartment side?

I received the above parts except the oil cooler itself and I have the radiator out and I am trying to figure out the pipes...without the oil cooler in hand it is difficult to visualize how the pipes interact with each other.

I might have received the wrong pipe...The "Inlet Pipe 25999420" is that a two pipe/hose assembly as shown in this picture...I ask because I received a pipe with rubber hose that is a single assembly and I cannot visualize what end goes where.

https://www.gmpartscenter.net/oem-parts/gm-inlet-pipe-25999420?origin=pla&msclkid=39e2ab88b1111c3f8076cbfe9f8cf07a&utm_source=bing&utm_medium=cpc&utm_campaign=Shopping - All .05 Nickle Bid&utm_term=4584001428987132&utm_content=All

I might have gotten the wrong part. The pipe assembly I received is GM 25999416 and it looks like this and the internet shows that the pipe is #2 in the attached diagram:

https://www.gmpartscenter.net/oem-parts/gm-inlet-pipe-25999416




THANKS!!!

View attachment 276290

You don't have a 6L transmission in a 2007. It's the 4L60E.

Your part number at top is wrong for the inlet pipe. The 25999416 that you received is the correct part. It goes from the TOP fitting on the side of the transmission to the DRIVER side of the trans cooler.

The Outlet Pipe 15779543 goes from the passenger side of the trans cooler and up to the top of the radiator coolant tank.

The existing line from the top of the radiator tank to the transmission is discarded.
 

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