Transmission Coolers

[YukonRog]

I tow a 7000# travel trailer with my Yukon denali. Tranny temps pulling a grade in hot weather would hit 235 which concerned me. The Tru Cool 40k btu unit would not fit where the OEM cooler was mounted and it seemed 40k btu was overkill. I opted for the 21k model 4587 from Tru Cool. It fit with few mods. Have to move the outside temp sensor and drill hole in the lower cowl to route lines, but was a smooth install. Brought the trans temp down by 35 degrees and now stays below 200. OEM cooler specs out at about 7500 btu and is undersized IMO. I did not bypass the radiator for reasons mentioned previously. Research into the 6 speed transmission in my Yukon shows it is rated to 300 degrees. Still seems higher than I want. Yukon tows nicely and mounting in front of radiator does not restrict air flow with model.

This all makes sense and is exactly what I was looking at. But going into winter here and for ease of installation and getting the vehicle running, I'm spending $59 on a aftermarket OE replacement cooler. This coming summer I'll re evaluate and either go with the Tru-Cool 21k LPD or a Derale with a fan and t stat. We've never towed anywhere near what you're towing with our Yukon. I have a Cummins Ram for towing houses. LOL!

 

[grapeguy]

Made a mistake on the model number, it is a 4589. On my Yukon, there is plenty of air flow through the grill, so a fan wasn’t necessarily. Also in tow mode the 2 high speed electric fans kick in sooner, boosting the cooling.

 

[emamon]

I drive an '08 Yukon XL Denali with the L92 6.2L. Same 6L80E transmission. I have 140K miles and bet that at least 20% of that is either towing a 5,800 lbs boat or a 6 x 12 enclosed trailer which has a wind drag making the Denali work harder than towing the boat. I am pure stock and have never had any need for any mods to the tranny cooler. Now, I have changed my DEX VI in the trans and T.C. @ 50K and 100K....

 

[YukonRog]

I drive an '08 Yukon XL Denali with the L92 6.2L. Same 6L80E transmission. I have 140K miles and bet that at least 20% of that is either towing a 5,800 lbs boat or a 6 x 12 enclosed trailer which has a wind drag making the Denali work harder than towing the boat. I am pure stock and have never had any need for any mods to the tranny cooler. Now, I have changed my DEX VI in the trans and T.C. @ 50K and 100K....

My '05 is a 4L60E. And frequent oil and filter changes is the key. It's suggested to change them every 30K miles. I looked up all my RPO Codes and it says I have the HD Tow Pkg. And I never had any problems until the original transmission's Planetary Gear went out. I completely believe the replacement was stone stock rebuild and that's led to it's failure. Then the last one was just a complete rip off. They installed a junk transmission and probably didn't even flush the lines. They are what they are. And there's something to be said about GM's Engineering and tests. Millions of those transmissions out there.

 

[SUP SR]

Did you bypass the radiator? And do you have the Thermal Bypass on it? Hopefully you mounted correctly too. I've seen a lot of incorrect installations. On the LPD's the inlet and outlet have to be at the top.

Sorry for the late reply. I did not bypass the radiator. I hooked up the same hoses that went to the old transmission cooler. I did mount it so that both inlet & outlet hoses feed from the top, not the bottom. I followed the instructions for how to mount it shown in this YouTube video:

.

So far, it has worked great, resulting in a 50 degree reduction in the temperature when it is 100 degrees in Houston.

 

[YukonRog]

Sorry for the late reply. I did not bypass the radiator. I hooked up the same hoses that went to the old transmission cooler. I did mount it so that both inlet & outlet hoses feed from the top, not the bottom. I followed the instructions for how to mount it shown in this YouTube video:

.

So far, it has worked great, resulting in a 50 degree reduction in the temperature when it is 100 degrees in Houston.

I actually watched this video before you sent it. This guy says he's does this in his business. I'm not sure about the zip ties on the bent rods. The idea of preventing the hoses from kinking is great, but I think I'd use geared clamps or something that won't deteriorate so quickly from the temps. I'd even be tempted to use 90⁰ elbows. But the more fittings, the more chances of leaks.

 

[grapeguy]

I saw that video too. I did use his system of rods and ties and it worked good. There are ties out there that are rated for high temp (300 degrees +) to address the issues you have. it has worked well for me.

 

[YukonRog]

I saw that video too. I did use his system of rods and ties and it worked good. There are ties out there that are rated for high temp (300 degrees +) to address the issues you have. it has worked well for me.

Yeah I've got a background in plastics so I know the rating is good for only so long. But I've also dealt a lot with 3M and they actually have metal zip ties. And get this, SS Velcro! It was developed for the space program (NASA) and is the toughest stuff I've ever seen. If you can imagine SS Hook and Loop, once it's locked in it's hard to separate. UV and heat protection for plastics has only advanced so much so depending on the environment it varies from 2 to 10 years on the advanced stuff. Just make sure you buy the good stuff and not the Harbor Freight Chinese stuff.