8hp70 heater bypass

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Bigskyroadglide

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Hemi 5.7, supercharged
I have it installed on my 16 laramie and I have not seen any ill affects from the install even in Montana winters. Granted it has not been super cold this year, only a couple below zero weeks. With the lowest being around -20 degrees.

I did not take out the active grill shutters on my 16, they work as designed and the truck comes up to heat as quickly as before. Also I left the factory thermostat installed as well. Only impact is lower Trans temp.
 
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Missouri2016

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St. Louis
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2016
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5.7
UPDATE:
Finally got some time to take the truck out on Sunday towing our boat(Approximately 5,200 lbs.) and trans temp never got over 185. Ran about 60 miles and most time it was 179 -180 and no whining.
Outside temp was 94F with 45% humidity. I have the bypass valve now, so if I have any trouble in the future I'll switch it out. I have a lifetime warranty through the dealer, so I'm not messing with it right now. These forums are a life saver. Trying to interact with the dealer anymore has become a nightmare.
Went on a long drive this week, and temp got back up to 215 degrees. Putting the bypass valve in tomorrow morning. Can't believe the thermostat is bad after less than a year. We'll see how it runs tomorrow.
 

Missouri2016

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Went on a long drive this week, and temp got back up to 215 degrees. Putting the bypass valve in tomorrow morning. Can't believe the thermostat is bad after less than a year. We'll see how it runs tomorrow.
Installed the bypass this morning with no issues. Let it warm up for a few minutes, ran it around the block to make sure all seemed right and took it on the highway for about an hour. Slowly warmed up to 145 degrees F., and ran/shifted smooth as silk. Never got above 145 F. temp at 75 MPH. Got home, took the old thermostat and measured the length of the wax motor at room temp. Put it in boiling water(212) and remeasured. Never did expand/open. Hard to believe the original lasted almost 7 years and this factory new one I installed last July is bad already. Glad we have some smart folks on the forum. I wonder how many transmissions have failed completely or failed prematurely due to this issue. I keep my dash screen set to monitor all the important parameters so I was able to see this happening. How many guys don't do this or don't have that option on their trucks.
 

BlownGP

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Houston/Baton Rouge
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2018 RAM Harvest New Holland Blue
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5.7
Installed the bypass this morning with no issues. Let it warm up for a few minutes, ran it around the block to make sure all seemed right and took it on the highway for about an hour. Slowly warmed up to 145 degrees F., and ran/shifted smooth as silk. Never got above 145 F. temp at 75 MPH. Got home, took the old thermostat and measured the length of the wax motor at room temp. Put it in boiling water(212) and remeasured. Never did expand/open. Hard to believe the original lasted almost 7 years and this factory new one I installed last July is bad already. Glad we have some smart folks on the forum. I wonder how many transmissions have failed completely or failed prematurely due to this issue. I keep my dash screen set to monitor all the important parameters so I was able to see this happening. How many guys don't do this or don't have that option on their trucks.

Makes you wonder right? I always keep temps on my screen because I'm a nut like that. lol
I could care less about MPG or digital MPH.

Glad Caulks bypass worked for you. It's a god send and mine temps never get over 160-170 in the dead of summer.
 

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