8hp70 heater bypass

Bigskyroadglide · Mar 16, 2024

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.

Missouri2016 · Mar 16, 2024

Missouri2016 said:
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 · Mar 17, 2024

Missouri2016 said:
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 · Mar 24, 2024

Missouri2016 said:
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 · Apr 8, 2024

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 · Apr 11, 2024

trowe1991 said:
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

skates15 · Jun 12, 2024

Is the 8HP Bypass valve from yourautohuckleberry a good thing to do for peace of mind? I have a 23 5.7 1500. I plan long road trips during summer weekends in Minnesota/Wisconsin.

JHoward · Jun 12, 2024

skates15 said:
Is the 8HP Bypass valve from yourautohuckleberry a good thing to do for peace of mind? I have a 23 5.7 1500. I plan long road trips during summer weekends in Minnesota/Wisconsin.

It's the best mode I've done.

Heat isn't a friend of your transmission.

skates15 · Jun 13, 2024

I've been monitoring the trans temp and it got to 190 today in mixed stop and go/highway driving for 20 miles. Outside temp is 84. Seems high to me.

G-Ride990 · Jun 13, 2024

skates15 said:
I've been monitoring the trans temp and it got to 190 today in mixed stop and go/highway driving for 20 miles. Outside temp is 84. Seems high to me.

Been keeping an eye on mine too. Starting to hit the high 110s in Az. Mine got up to 188 the other day, ordered the bypass earlier this week.

skates15 · Jun 13, 2024

G-Ride990 said:
Been keeping an eye on mine too. Starting to hit the high 110s in Az. Mine got up to 188 the other day, ordered the bypass earlier this week.

Did you order from yourautohuckleberry?

G-Ride990 · Jun 13, 2024

skates15 said:
Did you order from yourautohuckleberry?

Of course! Hit up Caulk before I ordered to make sure I got the right thing.

That is the right place to get it from though.

JHoward · Jun 13, 2024

skates15 said:
I've been monitoring the trans temp and it got to 190 today in mixed stop and go/highway driving for 20 miles. Outside temp is 84. Seems high to me.

I have @caulk04's by-pass for about a year.

While running my errands(50 mile round trip) today, my tranny's temp hit 145° on today's outside temp 96° ... not bad, not bad at all.

G-Ride990 · Jun 13, 2024

JHoward said:
While running my errands(50 mile round trip) today, my tranny's temp hit 145° on today's outside temp 96° ... not bad, not bad at all.

That's what I want!

skates15 · Jun 13, 2024

G-Ride990 said:
That's what I want!

Heck, yeah! I can't believe mine hit 190 for a 20 minute drive in 84 degree temp.

ramffml · Jun 14, 2024

So in the 5th gens, some guys are reporting transmission failure because something in the cooling system/exchanger fails and it allows coolant to mix with the transmission fluid.

Does this bypass solve that issue?

RamDiver · Jun 14, 2024

ramffml said:
So in the 5th gens, some guys are reporting transmission failure because something in the cooling system/exchanger fails and it allows coolant to mix with the transmission fluid.

Does this bypass solve that issue?

Is this the sort of failure you're referring to?

Transmission Heater failed

Hello everybody, 6 month ago, I had a 2020 Ram 1500 in my garage who had the transmission heater broken, the whole transmission fluid goes into the coolant and the tranny was completely broken. I replaced the tranny with a 2nd hand low miles, and take a new transmission heater. After that...

www.ramforum.com

.

ramffml · Jun 14, 2024

RamDiver said:
Is this the sort of failure you're referring to?

Transmission Heater failed

Hello everybody, 6 month ago, I had a 2020 Ram 1500 in my garage who had the transmission heater broken, the whole transmission fluid goes into the coolant and the tranny was completely broken. I replaced the tranny with a 2nd hand low miles, and take a new transmission heater. After that...

www.ramforum.com

.

It was on a different forum but yes that sounds similar.

caulk04 · Jun 14, 2024

No, my part won't solve that problem. That's most likely a failure of the physical heat exchanger in the unit and the fluids would still mix, though not as freely as they would stock.

Lysergic · Jun 17, 2024

Great thread. @caulk04 - many thanks for your contribution to the Ram community.

I ordered the bypass from yourautohuckleberry.com about a week and half ago. Arrived at the mailbox last week but had too many other projects this past weekend. It's on the list for next weekend. I've got just over 500 miles on my new 2023 Ram. The transmission temperature seems to stabilize around 185-190°F driving around town or on the highway in these 90°F+ temperatures we're having in SE Texas. Based on reading past posts in this thread, mine is "normal" for an unmodified 8HP.

The 8HP runs way hotter than I'm used to seeing on my 2012 with the 65RFE, which typically varies between 140-160°F in summer and 120-140°F in the winter. 252K mi. on the 65RFE, BTW. Still operating flawlessly. I've done regular fluid changes every 50K mi. since it was new. I can't help but think it's extended the service life of the 65RFE.

8hp70 heater bypass

Senior Member

Junior Member

Junior Member

Senior Member

Junior Member

Senior Member

Senior Member

Senior Member

Senior Member

Administrator

Senior Member

Administrator

Senior Member

Administrator

Senior Member

Senior Member

Senior Member

Senior Member

Senior Member

Member

Similar threads

Forum statistics

Share this page