Do Aftermarket Transmission Coolers Actually Work? Duramax, Powerstroke, Cummins 

How the hell does truck master always know exactly what mod I'm thinking about, and put a video out for it while it's in my shopping cart?

Great news to hear... glad you're sticking around. Faith is good 👍... great video and good information 👍 As always looking forward to seeing what's next. 😎

This is the video I’ve been waiting and that’s awesome news that everything got fixed on the channel. Very happy to hear that. I’m definitely getting mine. Installed pretty soon for my L5 P.

I’m glad to see your channel is back on track, excellent video Josh 👍😁

Keep in mind that stock one had quite a bit of fin damage. But either way it'll keep temps lower which is good.

Congrats on the news about the channel I’m happy to hear that

Love the video. I really like the install videos and I am glad to hear YT has resolved itself.

Good video Josh ! Btw I fly from France to Chicago last week and I stopped at Ryan’s diesel service on my way to Iowa. I spoken to him for a couple of minutes. Such a cool guy 👍🏻

Aftermarket trans cooler was a solid upgrade for my lb7. Dropped trans Temps by 20 degrees and engine Temps by 10 degrees. The mountains I'd overland on that would overheat my engine were no problem after that!

I bought this for my truck 3 years ago and it’s help a lot

Trans cooler upgrade is completely worth the peace of mind. On some of the older trucks, lb7, lly, lbz at least, it's well worth it to swap out your OEM transmission lines at the same time for more robust aftermarket lines. Get the confidence one of those tired old hose crimps doesn't let go, better serviceability, and any sludge that's built up in either is removed from the equation.

You should probably install the Wehrli Custom transmission thermostat bypass plug too. Synthetic trans fluids are not dependent on a specific temperature range to properly have the additive packages in them to perform properly compared to older mineral based trans fluids. The factory plugs have stuck closed. Great insurance policy.

Added the mitsimoto trans cooler on my 03LB7 along with a deep sump trans pan. Temps decreased apx 20 degrees cooler pulling heavy. Takes a bit longer to raise and lower temps. With deeper pan. Great investment!

Hell yeah buddy. Glad to hear ur get paid. L5P putting in work 💪

I'm so happy to see you back on. Was kinda of worried.

Hey glad everything worked out for you! Also my cp4 pump went out and 12k to fix everything…. Definitely need to do the swap

On my LMM, i installed the PPE transmission pan and so far only 190F with moderate weight in Virginia. The pan does reduce the ground clearance, but the logging roads i might drive in are usually graded enough for a Peterbilt to come out. For the 15 degree drop in temperature, that cooler is well worth it

They can’t keep the TRUCKMASTER down glad to see your back Josh!😊

100% agree with the aftermarket trans cooler. I installed one on my 2002 LB7 and it made a night and day difference. Haven’t pulled my 32 foot camp trailer with it yet but will coming up here in a couple of weeks for the deer hunt. Can’t wait to see the temps I get now.

It almost sounds as though there was a single person at RU-vid fucking with you Josh and they finally got caught. Lets hope so. Great video. People don't realize how beneficial an after market cooler is. Hot trans fluid is the number one killer of transmissions. I've never seen temps on my Allison above 180 degrees after installing mine and that's pulling 12k on a 100 degree plus day. They simply work!

I bought the PPE trans cooler for my LBZ because a deer hit crunched my OEM. I never really tow, and see the trans Temps 15 to 20 degree cooler cruising. I also did Deviant hydraulic transmission lines for maintenance.

RU-vid can never take down the best Duramax content there is Josh , you are the Best Brotha , Duramax Rule Brotha 👍

I put the mishimoto trans cooler in my lbz. Dropped the trans temps a good 30 degrees over the factory trans cooler. I was getting 105-115 over ambient towing the passes with my travel trailer. Now I am lucky if I get 90 over ambient towing and typically run around 70-75 over ambient not towing instead of 90-100 over. At the same time I did a coolant flush, cleaned my stack, and installed the upgraded kennedy fan clutch and it also helped keep my engine running cooler as well. The fan clutch kicks on at 198-200 degrees instead of 220-225 like the original would so my engine runs much cooler as well. The best upgrades I have done to any my trucks is upgrading cooling on both the engine and transmission.

Mine started to leak sunday... PPE got delivered today for $50 over oem from the dealership I figured why not upgrade....

Btw congrats on getting the RU-vid thing figured out. If u see this, from my understanding there is a way to submit ur video to RU-vid before it even gets released, to make sure all is good. DDE made a post to whistlin diesel about do that since they were having problem with that as well. Life of Palos was the 1 that mentioned it in a recent video. (Has a pic of cleetus & his wife as the preview of video)

What do you think of this?I'm thinking about installing an even bigger cooler,but above the rear axle between the frame rails.Yes,it'll have an electric fan pulling air thru it too since air flow won't naturally flow as much as factory location.The reason I'm hoping to mount it there is to reduce under hood congestion and find/fix potential leaks in future.Considering a pull off from a Kodiak type truck.Big,but still duramax/allison combo. Thanks for help. Thanks for your service and God continue to bless.

I just have to say,… my local earl hooked me up!! Thanks for your show boss!

That trans is known for The Transmission Thermostat to stick. You can install a bypass valve. I would only do it if towing a lot. Just did a 2018 and temps down to 174 degrees with 15K on.. Great Video! Love em !

The later LML and the L5P uses a thermostat to control temperature on the transmission. So the cooler will only help when the heat load exceeds the stock cooler.

Josh that brings a idea why not make and sell bumper extensions so the front bumper sits 3 to 4 inches forward it would provide a step to get under the hood easier

I have a 2019 Denali L5P, i installed the WC FAB bypass thermostat and while hauling my 15,500lb 5th wheel i've seen trans temps as hot as 140 degrees, on a 12hr trip,on the stock trans oil cooler.

Truckmaster is here to stay! 🙏

I’m glad your going to keep your videos going your videos what got me in to diesel trucks they are power houses lml Tennessee 😊

I am so glad your channel got re-monetized. You very much deserve it. I know you work hard to get these videos out to all of us. And there is solid value in your content. So there is every reason to get compensation for your hard work. I just wish Google would put the "Don't" back in their mission statement. God bless you and your family sir.

people kill me “the front grill”😂 where’s the rear grill😂. love the vids man

I’ve had the double stack trans cooler with the fan setup. I’ve hauled heavy loads over mountains in the west and in the south with my 06 lbz i never saw temps over 175-180. Big time worth it

Ive been wanting to put a aftermarket trans cooler on my 08 max but till now havent found a good one. My stays around 215-220 and this looks like would help with that for sure . Thanks

I did the Wcfab trans thermostat bypass plug on my L5P. Pulling my 38ft boat I never got over 207 on a 95 degree day

yes. makes about a 25 degree difference on mine. i have the one your holding

I did a direct fit aftermarket trans cooler on my lmm. I did notice around a 10 degree difference even in stop and go traffic. I also installed a trans go shift kit. Worth the money.

Keep up the great work Josh im a big fan of you and your truck content you inspire me for getting a Diesel truck thanks man I appreciate it 🙏🏻😂

Back when I was still truckin with the Zebra, I had a couple small but very powerful fans on a manual switch I could turn on for climbing mountains and to cool the trans faster on the way down. Also used it a lot during the summer running hard then getting into slow traffic. That trans was holding 2,500 pounds of torque and those fans always kept it under 200 degrees which was really impressive running in the southwest mountain ranges in the dry summer heat. I think the same concept/idea could be applied to just about any truck.

The biggest help on my truck was cleaning the radiator. Mine was half plugged with cattail fuzz and bugs

It's definitely worth it, remember transmission temperature is a silent killer, longevity is the best way of saying. Keep it cooler dude.

I went the Mishimoto transmission cooler route and 5/8 transmission lines. It mounted below my factory cooler. So thinking I could link the two together, also installed the PPE transmission pan averaging 160 degrees normal driving temperature. My cooler sets in front of my radiator with a gap of about 2 inches on my LMM.

I am replacing my blown cooler with this same one, 2015 3500, here in a few minutes it will be installed. I do haul a 17k tri axle camper, so I am looking forward to heat reduction.

Thanks for the video. My trans cooler caught a stone and has a small leak now so I’m in the market for an upgrade now. On another note what kind of rims are those? I might need to get some

L5P seems a bit lighter, glad to see!

Thanks😊

I bought a ppe trans cooler for my 330k mile lly because I tow a triple axle gooseneck trailer with trucks on the back and it never goes over 180 and before it would be over 220 when towing

Did one on my LBZ along with fleece performance cooler lines, ppe trans pan and pto side cover plates my temps dropped well over 30ish degrees

Hey Josh I pull for a living I drive a 23 model L5P and I run around 167-172 degrees loaded heavy! The highest i have ever seen was pulling a huge mountain loaded very heavy and I was barely over 200 degrees and cooled off as soon as I got rolling hood.I would look into wy your trans is runnning so Hot!

Don’t forget there’s a thermostatic valve inline with the cooler lines on these trucks. A cooler won’t do much until that valve is bypassed because it’s like a thermostat in an engine it wants the truck to heat up to a certain temp before allowed fluid through to the cooler

That RED truck sounds insane

I'm glad they have fixed your stuff bud

I added a trans cooler to my 2001 GMC Sierra 5.3L after finding my trans oil was black. Since the 1/2 ton didn't have a trans temp gauge, I added one as well. After flushing and replacing with synthetic trans oil, the temp only got to a high of 204° when pulling an 8k Travel trailer up over passes at 11,000 feet in the Colorado Rockies. This had that 5.3L in 1st gear working hard and needing air. On the highway towing it now stays a cool 165°. Going to get a Duramax someday but in the meantime, that trans cooler is great! I should add that after a season where the engine got hot towing, I replaced the thermostat, water pump, and fan clutch. Engine never overheated again. That fan clutch can slip and then nothing gets cooled properly.

Lowering your transmission temperature 15 degrees is definitely worth it.

I get around 30° difference on a hot day in the Ozark Hills: 30 foot camper loaded. 2002 LB seven built tranny.

On my 3.0 duramax, I used a PPE trans bypass and cooler. dropped my trans temp from 198 to 122 ish not towing. I think 140 is towing my boat. Real test in a few weeks

Do those 2500 trucks have the thermostat at the trans like the 1500 trucks do? If so get the bypass from ppe for that too and it'll really lower the temps... Great video man and glad to see you're back getting money from this.

L5p sounds great!

Did you ever do the bypass block or plug on your L5P? Before the trans cooler? Just a curiosity. Much love

That LBZ sounds wicked...buuuut that L5P though..... since the DPF was "cleaned out" it really sounds good! If I were a rich dude, I would sponsor an install video of a 64mm 9 blade, along with some Kryptonite front end goodies on that '18. But since I'm not rich, I digress. Still working towards my first diesel 🤷‍♂️ God Bless- Old Sarge from near Pensacola, FL.

My LB7 has the ZF6 but I have problems with the hydraulic clutch getting too hot and sometimes I get clutch fade. I have to pull off let it cool before it works right again, mostly in the summer, I’m in Texas so it gets hot.

That stock L5p sounds pretty good ;)

Even the upgraded trans coolers make a big difference on the gassers same as it does on the diesels.

i got my temp down to 160 with a heavy load in Arizona in the summer

tebgi a question regarding a 2004 lly that comes with a gdp tunner but it is not connected to the obd2 it helps me to verify codes but if I put an edge cts3 on it to look at the gauge information it will work as well it already has the 5 position switch

All you really need to do is install the WC fab transmission thermostat cooler bypass and it works like a charm.

is that the 9 blade turbo from rds on the red dmax? sounds crazy

i have been thinking about this upgrade for my EPC fooler LML duramax I see 200 degrees daily

I have 153771 on my L5P bought it with 138000. Should I change the transmission pan filter and fluid? And what fluid to use? I have amsoil engine oil, so don’t know if I should go with amsoil atf or ac delco? Thanks for the advice. Great video truck master I as well has this saved to buy.

I'm glad you mentioned it takes a little longer for the transmission to warm up, was wondering if it would make a difference for those plowing snow? Would it help keep the transmission cooler being worked?

When you did your tests - did you account for the outside air temp (OAT) on each test? That's really what will help you measure your transmission cooler efficiency. The delta between your OAT and trans temp is what you want to measure. I installed a larger cooler on my 09 Tahoe and dropped the delta to about 50 degrees from OAT at highway speeds, or 80 degrees delta from OAT while towing. So, if it's 100 degrees OAT out, the highest I see on straight and level while towing is 180. I also have a 24 Silverado 2500HD - I'm thinking about the PPE trans cooler for that. But don't know if I will see that much of an improvement.

After spending 8g on a built transmission the 400$ was definitely worth the peace of mind to keep the temps down

06 lbz 6 sp. with 5/8 cooler lines and upgraded trans cooler, when I was pulling a big grain cart I could only go about 50 mph or engine would get towards hot. I locked it in 4th and trans keeps heating up over 235, but if I let it go to 5th it didn't heat the trans as soon. I just added PPE trans pan too see if that helps.

Very nice truck! : ) What size wheels and tires are those? Thanks in advance for the info.

PPE doesn’t claim to lower your trans temps as contrary to belief, the main claim is that the transmission temperature’s are going to be staying lower and colder over a longer period compared to the factory cooler because of higher capacity and bigger cooling area

Just wondering if you should remove the trans oil thermostat (bypass valve). If the temps drop significantly, then maybe bypass valve needs upgrading.

My LML Duramax ran around 140 pulling a cat skid steer 2 hours from home did very well it was during November Thanksgiving break. So it wasn't normal Texas Temps

I drive hotshot all over country had a ppe cooler on my 21 duramax it lowered temperature a lot before I installed it transmission temp was always over 230 pulling heavy load’s threw mountains now have a 24 duramax need to get one for it

"This thing has a 36 gallon fuel tank"... Well I'm jealous. My truck used to have a 34 gallon tank. I say used to, because I bought a cheap, made in China fuel cap, and the vent didn't work. I drove for a couple of hours, stopped to refuel, and I didn't have the arm strength to remove the fuel cap. The vacuum was so strong, I had to pry the cap off. The vacuum caused the tank to start collapsing in on itself. Now my 34 gallon tank is about 26 gallons. I've since added a 88 gallon aux tank + tool box in the back, so not so bad. Just got a better quality cap for my aux.

can you do a double trans cooler? add it in series instead of replacing the factory one?

Hey, what's the best tuner I should get for my 05 lly duramax? I have a s&b intake and plate deleted 4inch exhaust pipe. I plan on doing some regional hotshoting with it

This l5p sounds good brother did you is it 5 inch straight pipe? Or what’s the exaust set up I want to delete mine and I’m deciding either do 5 inch or use the def cat and stock exaust…

I have 1 minor delima with temp readings .. what was differences in outdoor Temps... I'm Michigan as well and we know how it swings

Where is the best place to get a PPE lower radiator hose for a 2008LMM Duramax? Or do you sell them?

Hell's yeah my friend

I live in FL I have a l5p trans bypass plug from wheril haven’t seen above 200* towing drive around 150* $50.00

I’m waiting for Black Friday to pull the trigger on ppe for my lb7.

My 2018 3500 cummins with 68rffe towing never gets past 170F with factory cooler. 168 is where it stays normally.

Thick master., this comment is kind of off topic. I tried to find a spot to make this comment but this is the only way I can get it to you. I have a 2005 2500hd with the LLY and I’m sure you know about the LLY overheating when towing heavy loads. I guess they upped the performance from the 2001-2004 models but didn’t increase the cooling capacity on the lly. They did fix the problem in 2006 and up by increasing the cooling capacity. I researched the crap out of this issue and finally came to the conclusion that the only way guys have fixed this issue is by adding an auxiliary radiator. I am about to do the project myself but figured I would give you the opportunity to do a video on this subject even though I believe you don’t have an lly. I think it would help a ton of people out as the mod is hidden in the diesel forums but is the only proven fix with the 2005 lly. Thanks man. I watch all of your videos

do a update on the 6.0 powerstroke i love that thing one of the best 6.0 on youtube its right be hind the 6.0 f150 that freed diesel made

Seeing that you installed a little bit larger transmission cooler being up north, do you not run a cover over the front of your truck? It keeps all that harsh cold air from hitting the front.

Congratulations sir .

Mishimoto on my LLY was a major improvement

@Truck Master are you still running the Pulsar V3? What is your thoughts and gains any in mileage or just fun at the skinny pedal?\

How about run the transmission lines straight to the cooler and back to the transmission . Not going into the radiator see what the temp is

what kind of lift do you have on the LBZ and do you recommend it?

A video on my birthday!!!