Upgrading Trans Cooler 6.0L 2500?

rlme36 · February 6, 2020

This could be a case of me over building something/fixing something that isn't broke. On a tow this past summer I saw Trans temps ~200deg F and figured i'd look into upgrading the trans cooler before I need to tow again. I've searched and it doesn't seem to be a unit that is made for the 2016-2019 2500HD gas trucks. Is it because GM actually got it right the first time or not enough demand for aftermarket to bother? I realize the trans temp can go higher, but I've always gone with the assumption you can't really over cool the transmission fluid.

Thanks,

Rob

redwngr · February 6, 2020

I wouldn't even consider changing it if you're only seeing 200F.

200 is dead nuts centre of the 'normal' range on the gauge.

The trans fluid level check is a 2 step procedure. A cold check (between 80 and 90 F?), which is basically intended to make sure there is enough fluid in it to do the 'hot' check. If it passes tcold check, then ---

Hot Check Procedure
Use this procedure to check the transmission fluid level when the transmission fluid temperature is between 160 °F and 200 °F.
The hot check is the most accurate method to check the fluid level. The hot check should be performed at the first opportunity in order to verify the cold check. The fluid level rises as fluid temperature increases, so it is important to ensure the transmission temperature is within range.

rlme36 · February 6, 2020

Thanks for the response, that is very useful/interesting information. The other part for me is that I anticipate using this to haul an enclosed car trailer vs. an open car trailer, figured it would need the added cooling, but seeing that its right at factory spec, perhaps I'll wait and see how well it does in stock form. Maybe they did get it right

swathdiver · February 6, 2020

7 hours ago, rlme36 said:

This could be a case of me over building something/fixing something that isn't broke. On a tow this past summer I saw Trans temps ~200deg F and figured i'd look into upgrading the trans cooler before I need to tow again. I've searched and it doesn't seem to be a unit that is made for the 2016-2019 2500HD gas trucks. Is it because GM actually got it right the first time or not enough demand for aftermarket to bother? I realize the trans temp can go higher, but I've always gone with the assumption you can't really over cool the transmission fluid.

Thanks,

Rob

Get rid of the transmission's thermostat, that will bring down the temps without having to change the cooler out for a larger one. Well, I'm assuming the K2 HDs have one like the K2 1500s!

Where's Marty? He and a few other guys have taken care of that thing on their rigs.

Jeepplr · February 14, 2020

I have a 2002 2500HD 6.0 LQ4 4L80E.

It has a ProCharger that runs up to 8psi, really big fuel injectors, Snow Performance water/methanol injection starting at 2psi full 500cc/min at 5psi and a Black Bear tune. I pull a big horse trailer over the Colorado Rockies with my Jeep in the back and an RV in front. Full up and only 10 gallons of water the trailer weighs about 11,000 but has been up to 13,560 pounds once.

On long mountain pulls my trans would get very close to the red line. I did not like that so I could not just do a surgical strike I went full on nuclear. I have a universal 26,000lbs trans cooler down stream from the in radiator cooler that is in the Be Cool radiator. Now my trans stays on 120-150 and the engine on hard pulls in Ohio goes all the way to 180-190* in the summer. Winter I have it blocked almost completely to get heat.

My advice, a universal trans cooler and if you need more go with the Be Cool radiator.

SierraHD17 · March 10, 2020

On 2/6/2020 at 3:47 PM, swathdiver said:

Get rid of the transmission's thermostat, that will bring down the temps without having to change the cooler out for a larger one. Well, I'm assuming the K2 HDs have one like the K2 1500s!

Where's Marty? He and a few other guys have taken care of that thing on their rigs.

HD trucks don't have the thermostat in them. That's a half ton owners problem.

rlme36 · March 16, 2020

Still looking into this. the way i'd like to approach this is at least getting a fitting that goes into the factory lines without having to alter etc. Then I'll just use whats need to plumb into a good universal unit. Anyone know of a fitting that works?

Big Whiskey · March 17, 2020

Have you actually towed multiple times with your truck? If so, did the transmission run hot? My dad and I have both used our 6.0/6L90 trucks to pull campers from IL to CO (and through the mountains), and back home, in the summer heat without any problems. And, we both have homemade guards over the hole in the front bumper, which probably restricts a bit of airflow to the factory transmission cooler. My 1500 trucks would be at max temperature during various times on this same trip (both engine and transmission), but the HD's handle it with room to spare.

swathdiver · March 17, 2020

The warnings about transmission temperatures don't begin until you're over 260 degrees. Now you're transmission is made to handle this, it was literally designed to tow across Death Valley at full load. But the fluid would surely be degraded after a time at these temps and if it were mine, I'd change it.

I did a little towing over the last 36K miles (350 miles tops) since the fluid was changed and had Blackstone run an analysis the other day on it. They said it has 5-10K of life left in the trans fluid. I'm changing it as soon as new oil is delivered, not going to wait.

Lots of guys put those Tru-Cools 40K in their trucks in place of the original.

Z45 · March 17, 2020

Transmission temperature is dictated by the transmission oil itself. If you are so concerned with the temps then dump the low bidder supplier OEM fluid for a high end 100% synthetic ATF. Yet some will spend time and money installing high capacity trans coolers and but the minimum (OEM) quality ATF and never changing it. Some even advocating to NEVER change it.

You realize the same company who designs and implements the AFM system is the same that designs lube specs, right?

Edited March 17, 2020 by elcamino

rlme36 · March 17, 2020

11 hours ago, Big Whiskey said:

Have you actually towed multiple times with your truck? If so, did the transmission run hot? My dad and I have both used our 6.0/6L90 trucks to pull campers from IL to CO (and through the mountains), and back home, in the summer heat without any problems. And, we both have homemade guards over the hole in the front bumper, which probably restricts a bit of airflow to the factory transmission cooler. My 1500 trucks would be at max temperature during various times on this same trip (both engine and transmission), but the HD's handle it with room to spare.

I've towed with it a few times thus far, using an open car trailer. My question really comes from previous experience of trying to keep the temp as low as possible and the future upgrade to an aerodynamic brick of an enclosed car trailer. I may be over thinking it, but that's kind of the point. I'd rather err on side of over built vs. under. Appreciate the feedback Big Whiskey.

rlme36 · March 17, 2020

4 hours ago, elcamino said:

Transmission temperature is dictated by the transmission oil itself. If you are so concerned with the temps then dump the low bidder supplier OEM fluid for a high end 100% synthetic ATF. Yet some will spend time and money installing high capacity trans coolers and but the minimum (OEM) quality ATF and never changing it. Some even advocating to NEVER change it.

Agreed, heat is the enemy. I've already had the trans flushed by dealer with fresh fluid, more a function of my OCD and establishing a base line for powertrain warranty. If i go with a better oil product, no issue going that route either as i use Redline oil in most things, but unsure if GM will warranty using that product, but will look into it just the same.

flyingfool · March 18, 2020

install a 180 thermostat if your smart.. my 2012 2500HD trans runs a cool 120 stock, fully loaded 5000lbs trailer up mountain passes will hit 160 stock, no mods.. you new K2 HD's got some bugs to work out. katec sells the 180 motor thermostat , its the only aftemarket unit that works

Edited March 18, 2020 by flyingfool

sparky obrian · January 21, 2022

Interesting I have a 2001 2500hd and a 2014 2500hd both with the 6.o gas, under 150k miles and both trannys run very hot pulling a load up into arizona in the summer, running full syn, tranny fluid changed about at 50k . if im not careful they'll go over 260 , the 2014 is dealer maintained, im looking for after market coolers for both trucks.