Trucool 40K installed....review

[Sangster]

So my Denali has 147k miles on it and i've noticed the transmission lately has been always around 200 degrees, even when outside temp was in the 70's, no towing, highway, etc. Stop and go traffic and in the 90's and it would creep up to 210 or more.

The trans fluid is old and needs to be changed so I bought the fluid and a new filter. Haven't had a chance to change it all yet. But decided to go ahead this past weekend and swap out the OEM aux trans cooler for the Trucool 40k. Was a pretty easy job and took maybe 2 hrs, taking my time.

So far, I haven't seen more than 157 degrees in stop and go, in the 90's outside. On the highway, it sits pretty pegged at 135-140 degrees. So I'm seeing so far an average of 40-50 degrees less than before, same outside temp, same driving situation.

This week I'll change some fluid out (only changing out what comes with lowering the pan and changing the filter). That should help some too.

Anyway....good review, happy with the product!

 

[Geotrash]

So my Denali has 147k miles on it and i've noticed the transmission lately has been always around 200 degrees, even when outside temp was in the 70's, no towing, highway, etc. Stop and go traffic and in the 90's and it would creep up to 210 or more.

The trans fluid is old and needs to be changed so I bought the fluid and a new filter. Haven't had a chance to change it all yet. But decided to go ahead this past weekend and swap out the OEM aux trans cooler for the Trucool 40k. Was a pretty easy job and took maybe 2 hrs, taking my time.

So far, I haven't seen more than 157 degrees in stop and go, in the 90's outside. On the highway, it sits pretty pegged at 135-140 degrees. So I'm seeing so far an average of 40-50 degrees less than before, same outside temp, same driving situation.

This week I'll change some fluid out (only changing out what comes with lowering the pan and changing the filter). That should help some too.

Anyway....good review, happy with the product!

Thanks for posting your experiences. This is a topic I've been studying pretty exhaustively. I tow a heavy camper (6500 lbs) with my '12 XL Denali, so transmission (end engine cooling) are critical topics for me.

I installed a Tru-cool 40K last year, but discovered that it had a serious downside: it blocked the radiator enough for me to start to experience elevated coolant temperatures when towing in hot weather. Further, I learned that the 6L80 is designed to run hotter than previous generation transmissions. GM lists the minimum transmission fluid temperature for daily operation as 170ºF, and the maximum for normal use as 265ºF (this from a GM transmission engineer). Ergo, the 40K will overcool the fluid, which apparently can have other consequences, such as not boiling off moisture, etc. 190-200ºF is pretty close to ideal for these transmissions, so that's where the GM-designed cooling system likes to keep it. Unfortunately though, it's not enough for towing above 95ºF over mountains, so an aftermarket cooler is still needed in my case. I would never bother with an aftermarket cooler if I wasn't towing.

I removed the Tru-cool and went with a Derale fan-assisted cooler, mounted below and behind the front bumper. So far, I'm happy with the results. Others here have discovered the same as I've described above.

 

[ls1frc]

Thanks for posting your experiences. This is a topic I've been studying pretty exhaustively. I tow a heavy camper (6500 lbs) with my '12 XL Denali, so transmission (end engine cooling) are critical topics for me.

I installed a Tru-cool 40K last year, but discovered that it had a serious downside: it blocked the radiator enough for me to start to experience elevated coolant temperatures when towing in hot weather. Further, I learned that the 6L80 is designed to run hotter than previous generation transmissions. GM lists the minimum transmission fluid temperature for daily operation as 170ºF, and the maximum for normal use as 265ºF (this from a GM transmission engineer). Ergo, the 40K will overcool the fluid, which apparently can have other consequences, such as not boiling off moisture, etc. 190-200ºF is pretty close to ideal for these transmissions, so that's where the GM-designed cooling system likes to keep it. Unfortunately though, it's not enough for towing above 95ºF over mountains, so an aftermarket cooler is still needed in my case. I would never bother with an aftermarket cooler if I wasn't towing.

I removed the Tru-cool and went with a Derale fan-assisted cooler, mounted below and behind the front bumper. So far, I'm happy with the results. Others here have discovered the same as I've described above.

Would be nice to know if the better radiator makes any difference at all with the stock trans cooler.

 

[Foggy]

Would be nice to know if the better radiator makes any difference at all with the stock trans cooler.

I did the just the radiator at first.. I did it proactively when I installed my supercharger....
My trans temps and coolant temps were just fine... until towing heavy in warmer weather.
That's why I removed the OEM aux trans cooler and installed the derale remote with fan.

Since my intercooler was right in front of the aux trans cooler, I figured it was picking up
heat from it .. And now my trans runs a bit cooler even without the fan running on the derale.
I believe this is due to the intercooler being first in line for fresh air when the aux trans cooler
was right behind it

According to reviews, my mishimoto was supposed to drop trans temps (on a stock app) transmission
by about 20* with no other changes. The radiator is huge compared to stock... But fit
in like a glove with NO mods whatsoever

 

[CaptainAmerica1]

I haven’t towed with my Yukon but DD My Trucool stays about 40* higher than ambient. 138* is the highest I’ve seen it since the swap. We’ll see how it holds up here in Dallas in August.

 

[Geotrash]

I haven’t towed with my Yukon but DD My Trucool stays about 40* higher than ambient. 138* is the highest I’ve seen it since the swap. We’ll see how it holds up here in Dallas in August.

Yes, that's the experience I think most of us have had with the Trucool. It keeps the transmission cool - cooler than GM would like. The problem comes when towing something heavy with high wind resistance like a travel trailer, when the Trucool is mounted in front of the A/C condenser and radiator, then we start having trouble keeping the engine temps down, even with a larger radiator, as in my case.

 

[ls1frc]

I did the just the radiator at first.. I did it proactively when I installed my supercharger....
My trans temps and coolant temps were just fine... until towing heavy in warmer weather.
That's why I removed the OEM aux trans cooler and installed the derale remote with fan.

Since my intercooler was right in front of the aux trans cooler, I figured it was picking up
heat from it .. And now my trans runs a bit cooler even without the fan running on the derale.
I believe this is due to the intercooler being first in line for fresh air when the aux trans cooler
was right behind it

According to reviews, my mishimoto was supposed to drop trans temps (on a stock app) transmission
by about 20* with no other changes. The radiator is huge compared to stock... But fit
in like a glove with NO mods whatsoever

Yeah I have the Mishimoto too. Already had a warranty repair after 1 year. 2nd one is fine so far.

Fit and finish is good, but I am skeptical about the durability. It may have been caused by the old motor mounts though, I had the original one in with the stock mounts for 9 months and the H2 mounts for 3.

 

[Thatdesertviking]

So my Denali has 147k miles on it and i've noticed the transmission lately has been always around 200 degrees, even when outside temp was in the 70's, no towing, highway, etc. Stop and go traffic and in the 90's and it would creep up to 210 or more.

The trans fluid is old and needs to be changed so I bought the fluid and a new filter. Haven't had a chance to change it all yet. But decided to go ahead this past weekend and swap out the OEM aux trans cooler for the Trucool 40k. Was a pretty easy job and took maybe 2 hrs, taking my time.

So far, I haven't seen more than 157 degrees in stop and go, in the 90's outside. On the highway, it sits pretty pegged at 135-140 degrees. So I'm seeing so far an average of 40-50 degrees less than before, same outside temp, same driving situation.

This week I'll change some fluid out (only changing out what comes with lowering the pan and changing the filter). That should help some too.

Anyway....good review, happy with the product!

Thanks for the information. I just purchased my Yukon last month and had a Silverado previously with the 4l60 and had a Trucool on it. I noticed right away that the 6l80 definitely runs higher and I live in Vegas so I’m seeing temps in stop and go ranging from 190 to 210. We had 118 here two weeks ago! So I’ve ordered my Trucool, but I’m curious where did you locate yours and did you bypass the radiator? I’m already planning that it should go under the steel bumper behind that lower valance grill. Also are you running it alone or did you add fans?

we just did a 2800 mile trip in it and it performed beautifully aside from some wheel and tire issues. That got solved yesterday with a new wheel/tire setup that will be installed this weekend. More appropriate for a 4wd.

Im excited to start on this project get and the tranny temps in check.

 

[Geotrash]

Thanks for the information. I just purchased my Yukon last month and had a Silverado previously with the 4l60 and had a Trucool on it. I noticed right away that the 6l80 definitely runs higher and I live in Vegas so I’m seeing temps in stop and go ranging from 190 to 210. We had 118 here two weeks ago! So I’ve ordered my Trucool, but I’m curious where did you locate yours and did you bypass the radiator? I’m already planning that it should go under the steel bumper behind that lower valance grill. Also are you running it alone or did you add fans?

we just did a 2800 mile trip in it and it performed beautifully aside from some wheel and tire issues. That got solved yesterday with a new wheel/tire setup that will be installed this weekend. More appropriate for a 4wd.

Im excited to start on this project get and the tranny temps in check.

My advice after having my transmission cooler set up both ways, is DON'T bypass the radiator's cooler in the setup. When I took mine out of the loop, my peak transmission temps were 30ºF higher than with it plumbed in. And this is confirmed the GM upfitter's guide, which says to plumb any transmission coolers in AFTER the radiator.

I have a Derale cooler (fan-forced) on my '12 and a Tru-Cool 40K on my '07. If you're not towing, you can get away with the Tru-cool mounted in front of the A/C condenser. But if you're going to do any towing at all, you want it mounted below the bumper and behind the lower valence grille. That way it won't interfere with engine cooling. I have a whole thread on here with my saga of getting my cooling system sorted for towing in hot weather.

Even in Vegas, with the tru-cool you'll have trouble keeping transmission temps above the 170ºF minimum that GM recommends for the 6L80. In my opinion, the Derale is a better solution for keeping the transmission in its happy place, between 170 and 190 in almost any circumstance, and below 200 towing on the highway.

 

[Sangster]

Just realized I never replied to this thread with an update.

After the Trucool install, the trans stays a good temp, 145-165, maybe 175-190 when towing on a really hot day in stop and go traffic.

The coolant temp is a different story. If I drive around town for a bit, I'll get coolant temps that were getting up to 230ish. Replaced the thermostat, radiator, hoses, water pump. No change. With my Blackbear tune, the fans would go to High at 225 degrees and then back to low at 212 degrees. Up and down, up and down. With the AC on, temps will go up to 225-230 when idling. I flashed back to stock and fan temps were 230 to high and 220 back to low. Dumb. So yesterday Blackbear changed my file to lower temps. Now, high kicks on at 210 and back to low at 203. Perfect. Now to deal with the AC on temps. I'm convinced 100% that it's the Trucool dumping heat into the AC condenser/radiator. So I'll be moving it down below the radiator next. Initially, I'll see how the trans temps do without a fan on it. If it's not cooling like I want, I'll put a fan on it.

I'll post an update.

 

[Sangster]

So I moved the Trucool down below the bumper and opened up the fake lower Denali grill to allow airflow. Drove around in some rush our stop and go traffic to see how it would do. Ambient temp was 95ish. A/C stayed cold the whole time (when really hot, the A/C would struggle before). Engine coolant temp got up to 217 for a few minutes when sitting still in traffic, but mostly stayed 205-215. Trans temp went up to 181 in stop and go traffic. No fan on the trucool anymore, so I think in 95 degree stop and go traffic, this was acceptable. We'll see how it handles towing the boat soon. Jumped onto the highway and the coolant temp dropped to a steady 200-205. Trans temp dropped to 162-165.

So far so good with moving the trucool away from in front of the radiator. It's really hot here in FL right now, so I'll keep watching the temps and report back.

 

[Geotrash]

So I moved the Trucool down below the bumper and opened up the fake lower Denali grill to allow airflow. Drove around in some rush our stop and go traffic to see how it would do. Ambient temp was 95ish. A/C stayed cold the whole time (when really hot, the A/C would struggle before). Engine coolant temp got up to 217 for a few minutes when sitting still in traffic, but mostly stayed 205-215. Trans temp went up to 181 in stop and go traffic. No fan on the trucool anymore, so I think in 95 degree stop and go traffic, this was acceptable. We'll see how it handles towing the boat soon. Jumped onto the highway and the coolant temp dropped to a steady 200-205. Trans temp dropped to 162-165.

So far so good with moving the trucool away from in front of the radiator. It's really hot here in FL right now, so I'll keep watching the temps and report back.

Nice. I think that was a wise move for trucks with the 6.2. In theory, they generate 17% more heat than the 5.3, yet use the same cooling system. People with the 5.3 seem to be able to get away with the Tru-Cool being in front of the radiator, even when towing, but people with the 6.2 start running into problems with that arrangement.

 

[gooffeyguy]

I originally bought a TruCool 40k to install a couple years ago, but after realizing how large it was I decided on a Derale stacked plate model that is the same width as the OE one but a bit taller and a lot thicker. It was even thicker than the TruCool and also had a btu rating very close to the TruCool.

 

[Geotrash]

I originally bought a TruCool 40k to install a couple years ago, but after realizing how large it was I decided on a Derale stacked plate model that is the same width as the OE one but a bit taller and a lot thicker. It was even thicker than the TruCool and also had a btu rating very close to the TruCool.

That sounds like another reasonable solution that I didn't know about. What model Derale did you use?

As I think about this though, for my purposes which includes a lot of towing a heavy camper (as you know but others may not), I still think there is meaningful benefit to putting the transmission cooler out of the airflow path to the radiator. The disadvantage to mounting it low as many of us have, is that it's possibly more vulnerable to damage from road debris, although mine is fully protected by the steel bumper and the steel frame crossmember tube behind it.

 

[gooffeyguy]

That sounds like another reasonable solution that I didn't know about. What model Derale did you use?

As I think about this though, for my purposes which includes a lot of towing a heavy camper (as you know but others may not), I still think there is meaningful benefit to putting the transmission cooler out of the airflow path to the radiator. The disadvantage to mounting it low as many of us have, is that it's possibly more vulnerable to damage from road debris, although mine is fully protected by the steel bumper and the steel frame crossmember tube behind it.

I believe it is the 10000 series 19 row model 51978 or the 25 row model 52578, can't remember which. They're both 2" thick and instead of the AN fittings I used spring clip fittings that take the OE lines.

I don't do a lot of heavy towing and it works good for me.

Your setup under the bumper has a fan on it, right? I think that's ideal for max towing.

 

[Geotrash]

I believe it is the 10000 series 19 row model 51978 or the 25 row model 52578, can't remember which. They're both 2" thick and instead of the AN fittings I used spring clip fittings that take the OE lines.

I don't do a lot of heavy towing and it works good for me.

Your setup under the bumper has a fan on it, right? I think that's ideal for max towing.

Thank you. I will look into that one to replace the 40K I currently have on our 2007, which I don't use for towing.

Yes, I have the 13960, I believe. It does have a thermostatically-controlled fan, and it works fabulously for heavy towing. Both the engine and transmission run significantly cooler with this setup than with the factory setup when towing in hot weather.