8hp70 heater bypass

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CanuckRam1313

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Is this designed to regulate trans temperature lower than factory setting and what are you trying to set parameters at
Thanks Bruce
At continuous highway speeds I see up to (give or take) a 30deg/c reduction in trans heat vs the stock factory set up.
In-town or traffic I see (give or take) a 15 to 21 deg/c reduction in trans heat vs the stock factory set up.

With this mod I also see an overall reduction in engine coolant temps as well, especially at continuous highway speeds (say about 5 to 7 deg/c, or so).

Zero negative affects on the transmission operational characteristics in harsh winter climates either (I'm talking Ottawa Valley & interior QC type winter temps).

A must-have upgrade for those keeping their trucks long-term, and especially if you two or haul as well.
 

ffeschjeff

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Just got my bypass put in! Hardest part was getting the snap ring off with my crap plilers. The cap took some work, but I really just needed to yank on it a couple times and it popped out. Outside temps are a bit cooler then my first picture but below are my results
 

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ffeschjeff

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Just got my bypass put in! Hardest part was getting the snap ring off with my crap plilers. The cap took some work, but I really just needed to yank on it a couple times and it popped out. Outside temps are a bit cooler then my first picture but below are my results
Here my Hot day result! Very pleased!
 

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caulk04

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I've been playing around with this lately and I know there's a lot of you curious on just how it works and looks, so here ya go:

Red arrow shows the port where fluid enters the TMU from the trans.
Blue arrow shows fluid exiting the TMU manifold into the heat exchanger (heater)
Blue circle is heated fluid returning from heat exchanger which then reenters the trans
Green arrow shows fluid leaving the TMU manifold going to the trans cooler/ac condenser up front.
Green circle is cooled fluid returning from the cooler reentering the trans.

View attachment 549137

This cutaway shows what's packed into this housing as factory, plastic cap and thermostat inplace (fluid routing to heater):

View attachment 549138

Here you see the bypass valve installed. Fluid flows only through cooler circuit, heater circuit is blocked

View attachment 549145

Here you see the bypass installed WITH the new aluminum cap I'll have available shortly. No telling where the restriction in this system is now, but it is decidedly NOT here. MUCH more open in this arrangement.

View attachment 549146
 

Wild one

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Great pics Jesse,thank-you for taking the time out to explain how the tmu works for alot of guys.
 

G-Ride990

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Does this bypass work on a 5th gen? My truck got smoked the same week I ordered your bypass, would love to put it in my new truck.

Sorry if this question has been asked an answered. Lot of pages to sift through.

Thanks!
 
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caulk04

caulk04

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Does this bypass work on a 5th gen? My truck got smoked the same week I ordered your bypass, would love to put it in my new truck.

Sorry if this question has been asked an answered. Lot of pages to sift through.

Thanks!
Yessir it will. So far it fits every 8spd equipped Ram 1500
 

skates15

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Just got it installed with the aluminum cap. Temps have been reduced by 20, 30 and 40 degrees!!

The cap and components are well made and the cap should last a long time.

I'm impressed with the mod and Caulk has been very helpful answering my questions.

The reduction in temps is amazing!

Thanks Caulk!
 

Bobwa

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I'm a nubi here and not certain how this fourms works, so please excuse me if I do something I'm not supposed to.

I have a 2020 RAM 1500 that just had a new transmission put in under warranty after 47K, my first long drive with the new trans saw temp in the 240 range. And you all know the rest of the story "RAM says that's normal". They won't do anthing and would rather toast another, I'm old school and that's BS. I now only drive the truck in the city because the temps stay around 190-200

After a ton of reading has let me here, where the real geniuses come up with the solutions. I'm extremely interested in the solution Mr. Caulk04 has come up with. Sir I am definitely interested in what you have come up with and would love to purchase when you make some.
 
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caulk04

caulk04

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I'm a nubi here and not certain how this fourms works, so please excuse me if I do something I'm not supposed to.

I have a 2020 RAM 1500 that just had a new transmission put in under warranty after 47K, my first long drive with the new trans saw temp in the 240 range. And you all know the rest of the story "RAM says that's normal". They won't do anthing and would rather toast another, I'm old school and that's BS. I now only drive the truck in the city because the temps stay around 190-200

After a ton of reading has let me here, where the real geniuses come up with the solutions. I'm extremely interested in the solution Mr. Caulk04 has come up with. Sir I am definitely interested in what you have come up with and would love to purchase when you make some.
The bypass valve itself is available at this link If you're also interested in the new aluminum cap I'm making (optional) you can contact me directly here or at [email protected]
 

EdGs

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I'm a nubi here and not certain how this fourms works, so please excuse me if I do something I'm not supposed to.

I have a 2020 RAM 1500 that just had a new transmission put in under warranty after 47K, my first long drive with the new trans saw temp in the 240 range. And you all know the rest of the story "RAM says that's normal". They won't do anthing and would rather toast another, I'm old school and that's BS. I now only drive the truck in the city because the temps stay around 190-200

After a ton of reading has let me here, where the real geniuses come up with the solutions. I'm extremely interested in the solution Mr. Caulk04 has come up with. Sir I am definitely interested in what you have come up with and would love to purchase when you make some.
My '15 stays right around 190°, I'm not sure I've ever seen it over 195°.

I do not have @caulk04's bypass yet, but hopefully will in the not too distant future.

If your trans was hitting 240°, I would say that's definately no bueno. Way too hot, IMO.

Please keep us updated.
 
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