8hp70 heater bypass

if the position of the 3 way valve controlling bypass temp is pid controlled why can't the temp be changed with a tuner?My thought being if you could manipulate this temp input, bypass the wax pellet in the TMU and then put a proper tstat unit in the external lines you could have the best of both worlds.

I think you could TIG these AN bungs to the factory lines and then Bob's your uncle

HEMIMANN said:

85C is too hot.
MOPAR says it's "normal".

It wasn't "normal" before they started screwing around adding thermostats. I wrote up a page of nominal oil oxidation life vs temperature. Running elevated temps means frequent oil changes, which are a beetch to do on a ZF.

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I don't know enough about the ZF and the fluid they use to know what's acceptable; possibly 85 is too hot, but I was impressed that my temps while towing were actually in the range Ram was targeting (so the ZF can easily handle towing). Apparently they target 87 degrees.

We get benefit from bringing both of them [oil and transmission fluid] up to operating temperature faster. The primary benefit comes in the transmission. In colder climates, you could drive a vehicle for hours in the winter and the transmission might never reach that 190° (F) for the most efficient operation. So what we do is use some of that hot engine coolant through the heat exchanger to bring it up to 190° as quickly as possible, and that gives us efficient operation very quickly.

2013-16 Dodge Ram pickup trucks: Engine, Transmission, Axles

2013-16 Dodge Ram pickup trucks: Engine, Transmission, Axles 2013-2016 Ram 1500 • Dodge - Ram Central • Features, Interior, Styling • Suspension The 2013 Ram 1500 achieved best in class gas mileage with the V6 and V8 engines, thanks largely to the new "TorqueFlite 8" automatic transmission...

www.allpar.com

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I will definitely be changing my transmission oil at the end of this towing season though, I'll be sitting between 60k to 70k miles by then.

Long and interesting thread. @caulk04 are you still selling your part if so how do I get one ? 2022 Ram 5.7 with 8 speed 8HP75 transmission.

I need some help,

After a failed install, unable to remove the black plug, I reinstalled everything including the snapring and went on a drive. I guess I don't have the snapring fully installed correctly, because the plug blew out on the highway and made a nice smoke show.

Does anyone know if there are readily available replacements for said snapring?


Edit: if anyone happens to have the same situation happen to them, or just happens to lose the snap ring when trying this job, harbor freight has a kit that has the perfect size.

Fluid was $35 at my dealer and despite it looking like I dumped all the fluid out, I only had to put in 3 quarts. (Had to pen the 4th bottle cuz my pump was too small to get the last 100ml out of every bottle)

Harbor freights fluid pump isn't the right size however AutoZone had the correct one.

Fluid cost: $35x4=$140
AutoZone fluid pump=$12
Harbor freight snap ring kit $5
Total: $157


Don't make a $160-$3000 mistake, MAKE SURE YOU PROPERLY INSTALL YOUR SNAPRING


As for the bypass valve, I have it installed (as installation was easy since the black plug ejected itself) and the highest temp I've seen in my 20 minute test ride was 140 degrees! Doing good so far, previously the temp would be up to 195 by then

Edit 2: you potentially will have an easier time pulling out that black plug if (before removing your snapring) you get the transmission warm, go for a 5 minute drive, come back and pop that snapring off and the black plug should just pop out in theory.

I just hate when projects go SNAFU. Glad it ended up ok for you though!

Just an FYI for anyone interested, I will probably no longer offer these in the next couple months. I'll be moving to a new position in my company with much less shop floor time and less opportunity to make these.

@caulk04 it'll be a loss to us here, but I hope your new position is a better one. You deserve it!

You may want to see if someone is interested in buying our licensing your design for commercial sale. There are a couple of large retailers like, Genos Garage, that specialise in Ram after market gear. Best of luck in your new job.

This @caulk04 designed product is such a fantastic upgrade for our 8spd transmissions.

If anyone is on the fence, get off it and get this part before they're no longer available.

I've had mine in for a good while and many miles thus far and the benefits are real. Works flawlessly and does exactly what it was designed to do without issues.

CanuckRam1313 said:

This @caulk04 designed product is such a fantastic upgrade for our 8spd transmissions.

If anyone is on the fence, get off it and get this part before they're no longer available.

I've had mine in for a good while and many miles thus far and the benefits are real. Works flawlessly and does exactly what it was designed to do without issues.

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Glad I got one while they were available, had it in a couple years and it works great.
Caulk, hope your new job goes well.

caulk04 said:

I just hate when projects go SNAFU. Glad it ended up ok for you though!

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Can say it's running great now! Very much appreciate the bypass, saddened that you are gonna stop making them. My average is 120 degrees with my engine at 170-185 and when I drive I'm typically driving 50-70 miles at a time

Is this of any benefit for us guys in 5th gens? We're running the 8hp75 IIRC.

Yep, it fits the 8hp75 in 1500's as well.

Still sitting on mine. Bought the MaxCare plan right after I purchased the transmission thermostat so have been reluctant to install. These transmissions so rarely have issues, I’m contemplating tossing it in anyhow. If it ***** the bed, it will be after the 125k warranty anyhow because of the heat. Currently at 41k miles on 21 4x4 Laramie. Rear window leak has been biggest issue with rig.

caulk04 said:

Just an FYI for anyone interested, I will probably no longer offer these in the next couple months. I'll be moving to a new position in my company with much less shop floor time and less opportunity to make these.

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How many you have left?
I wouldn't having an extra if I get another ram or have to replace the trans.


I still love mine. Trans Temps never go over 150* even in 95* weather!!!

I just got around to doing this after seeing transmission temps spike to 228 while driving on I-20 through Alabama and Mississippi. It scared me so I slowed down and took extra time coming home. Installed this kit and it has been a game changer. Can’t wait to see how the temps are at 80mph

I didn't read the whole thread, I'm kinda interested, what do these cost or should I just PM you @caulk04 ?

Always best to pm, hit me up.

RamBayou said:

I just got around to doing this after seeing transmission temps spike to 228 while driving on I-20 through Alabama and Mississippi. It scared me so I slowed down and took extra time coming home. Installed this kit and it has been a game changer. Can’t wait to see how the temps are at 80mph

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Welcome to the very exclusive club of winning the temp spike bed crapping transmission lottery! @caulk04 's part is a life saver for us rare few.