8hp70 heater bypass

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Bigskyroadglide

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2014
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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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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.
 

trowe1991

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I have been following this thread for a couple of years now, and after getting fed up with seeing 180-190 trans temps, I bit the bullet and got one of Caulk04's bypass valves. Installation is straight-forward, basic tools gets the job done. I am a 10 year heavy equipment tech, no shortage of tooling here.

I will list my mods and typical temperatures, and then the updated temperatures.

2017 Ram Rebel, 5.7 Hemi, 3.92, 8spd, tuned by Jay Greene. 185F coolant thermostat, clutch fan delete/V6 e-fan conversion, no AGS from factory. Eaton TrueTrac rear differential. 144k miles. Had the truck since it rolled over 100 miles. (This truck is taken very well care of, and my woman makes sure to let me know that when I spend too much time on "upgrades" lol)

Typical temps I see every day on my 65 mile commute to and from work every day:

Coolant- 185F
Trans- 180-185F, 190F after sitting still in traffic
Engine oil- 190-200F

After installing the bypass, I am noticing my truck is holding onto gears longer, and it has a firmer, more positive engagement. I am very pleased with how well this part is doing to regulate the trans temps. After initial install, I took a 20 mile stroll around the country, and barely broke 120F. Later in the day, went on a 75 mile trip on I55 running 85-90mph, 78F ambient temps, and the trans settled in at 138F. Highest I have seen in the past week since install is around 145F, and I was making that Hemi talk, let me tell you!
 

BlownGP

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I have been following this thread for a couple of years now, and after getting fed up with seeing 180-190 trans temps, I bit the bullet and got one of Caulk04's bypass valves. Installation is straight-forward, basic tools gets the job done. I am a 10 year heavy equipment tech, no shortage of tooling here.

I will list my mods and typical temperatures, and then the updated temperatures.

2017 Ram Rebel, 5.7 Hemi, 3.92, 8spd, tuned by Jay Greene. 185F coolant thermostat, clutch fan delete/V6 e-fan conversion, no AGS from factory. Eaton TrueTrac rear differential. 144k miles. Had the truck since it rolled over 100 miles. (This truck is taken very well care of, and my woman makes sure to let me know that when I spend too much time on "upgrades" lol)

Typical temps I see every day on my 65 mile commute to and from work every day:

Coolant- 185F
Trans- 180-185F, 190F after sitting still in traffic
Engine oil- 190-200F

After installing the bypass, I am noticing my truck is holding onto gears longer, and it has a firmer, more positive engagement. I am very pleased with how well this part is doing to regulate the trans temps. After initial install, I took a 20 mile stroll around the country, and barely broke 120F. Later in the day, went on a 75 mile trip on I55 running 85-90mph, 78F ambient temps, and the trans settled in at 138F. Highest I have seen in the past week since install is around 145F, and I was making that Hemi talk, let me tell you!

Did you notice a difference in performance or cooling with the V6 e-fan? I thought the 2013+ stock e-fan was enough with deleting the clutch fan?

Also, you liking Jays tune. I've known him for a while but never got a tune because I don't want to run 93.. I burn enough of it in my Mustang. hahaa
 
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