8hp70 heater bypass

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EdGs

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Also found an Australian sds for 8+9 speed atf mopar 68218925AA and it had very little info on the properties.

Lots of no data available, etc.

In fact, it only had the viscosity at 40°C listed.
Also, it listed the color as red, which is BS
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Different Drummer

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My wife already warned me about this.

Seriously though, I do have about 1-1/2 qts. of Mopar fluid on the shelf. I have about 3 k to go before I get the next drain and refill.

I will get a measuring cup/beaker ordered up to try this out. Oh yeah, and the wife is like, "What do you want to do that for?" I almost said, "Because I have a *****.", but held my tongue....lol
Get an actual beaker that is graduated and has the beaker shape. An open top cylindrical shaped container may allow evaporation and skew your results. Even better would be a beaker with a stopper and small glass tube just to vent it. Yeah, I know I am being ****.
 
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caulk04

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For anyone interested, I have some made up and ready to go out. $30 shipped. IMO this is a better option than the Revmax kit and even though they claim the stock cap is prone to breakage so they've made the cap brass, I can't imagine the cap ever breaking as with my part there is less spring pressure on the cap.

PM for info please.
 
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caulk04

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Putting this here as at least a temporary informational post for installation.

First is the parts you'll pull out of the thermostat housing.

Second and third are the parts you'll put back in.

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- Remove the factory thermostat and spring from the thermal unit.

- Slide the factory thermostat off of the small pin and replace it with the new valve. Be sure the pin is seated in both the valve and the cap.

- Insert the new assembly into the thermal unit. It should go nearly all the way in, then require light pressure with one finger to compress the spring then a bit more to seat the o-ring of the plastic cap. Reinstall the snap ring. Be sure the snap ring is seated into the groove!
 

JS4024

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If you live in Florida fine, but lowering the temp will do more damage than leaving it higher. The transmission is designed to run at a higher temp. I tow up to 11,000 on my 2500 interstate driving in summer and my temps don’t get over 175 - 180 tops.
 

crazykid1994

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If you live in Florida fine, but lowering the temp will do more damage than leaving it higher. The transmission is designed to run at a higher temp. I tow up to 11,000 on my 2500 interstate driving in summer and my temps don’t get over 175 - 180 tops.
On your 2500. And towing doesn’t go over 175-180. Our temps are 185-190 regular unloaded. Also lower temps are better at putting power to the ground because the fluid isn’t thinned out as much. Lower temps also help prevent clutches from burning under stress. Also they used to run the transmission in your truck at lower temps before they started trying to get every mpg possible. That’s why everything has heaters built in now.
 

Wild one

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If you live in Florida fine, but lowering the temp will do more damage than leaving it higher. The transmission is designed to run at a higher temp. I tow up to 11,000 on my 2500 interstate driving in summer and my temps don’t get over 175 - 180 tops.

If you hung 11,000lbs behind the bumper on a 1500,the tranny would be at 240 + in about 2 miles,lol. The majority of HD's with the 6.4 and 8HP75 are running right around 160/165 when unloaded ,from the majority of guys i've talked to.The thermostat in the 8HP70 used in the 4 th Gen 1500's doesn't open till 180F,and from what i've gathered up,they use the same thermal unit in the 5th Gen 1500's with the 8HP75,and their 8HP75 tranny runs between 185/190 on the 5th gen 1500's.The HD's with the 6.4 and 8 speed use a totally differant bypass set-up,and they run noticably cooler then the 8 speeds in the 1500's do.
Question would be why do the 2500's /3500's with the 8HP75 run in the neighbourhood of 20/25 degrees cooler then the 8HP75 does in the 1500's when both are running down the road unloaded,kind of makes you think even FCA knows they'll live longer when run cooler. Your 2500 also doesn't pre heat the tranny fluid with engine coolant,why do you think they do that,plus the cars don't pre heat the tranny fluid either. You have to be beating the living hell out of my wifes 8speed in her 6.4 Challenger to get it above 165F,plus it'll take in excess of 50 miles before it'll reach 140F if you're driving it decently.
Lets compare temps when unloaded,as you're a bit unrealistic comparing temps when you're towing 11,000 lbs,as no 1500 should ever tow 11,000lbs,and the majority of 1500 trucks on the road don't tow anything,or even carry anything other then a bag or 2 of groceries in the box.
 
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caulk04

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Being designed to run hot is obvious. But it's in the name of efficiency (.001% nitpicky margins) and ultimate longevity isn't the name of the game. 100ºF isn't what I want my trans to run at, but I don't feel it's bad for it on cold days. I'm hoping to see ~130 typical and maybe 150 or so loaded.

At the end of the day, I made this part for me and for the time being I'm entertained by making extras, having civil discussion about it and selling some to those interested. Clearly at $30 it's not a get rich scheme. FWIW, it costs me $4 to ship one, $1 for the spring, ~$1.50 in material plus my time.

Back on topic, I currently have 7 unspoken for and ready to ship. Beyond that, I'll have to buy more springs to continue which is no big deal if there is interest. Or perhaps some other manufacturer would be interested in making it...
 

Wild one

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Being designed to run hot is obvious. But it's in the name of efficiency (.001% nitpicky margins) and ultimate longevity isn't the name of the game. 100ºF isn't what I want my trans to run at, but I don't feel it's bad for it on cold days. I'm hoping to see ~130 typical and maybe 150 or so loaded.

At the end of the day, I made this part for me and for the time being I'm entertained by making extras, having civil discussion about it and selling some to those interested. Clearly at $30 it's not a get rich scheme. FWIW, it costs me $4 to ship one, $1 for the spring, ~$1.50 in material plus my time.

Back on topic, I currently have 7 unspoken for and ready to ship. Beyond that, I'll have to buy more springs to continue which is no big deal if there is interest. Or perhaps some other manufacturer would be interested in making it...

I kind of wonder what the temp differances might be,if any,between the way CrazyKid and i did the bypass mod,and your thermostat bypass.On paper CrazyKid and i should run cooler,as theoritically there should be more fluid flow to the tranny cooler,plus we've lost one insulating factor with the heat exchanger not blocking airflow to the side of the fluid router.
It's one thing that i've wondered . Crazy Kid i think you should take Caulk up on his offer of a free one,and pop it in,to see if there is any temp differance between full flow,and a slightly restricted flow to the cooler
I'd buy one,but by the time it's sitting on my doorstep,it'd be probably double the cost,aarrgghh,lol.There's times it sucks being a Canuck,lol
 
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caulk04

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I don't think the ports in the thermal unit are large enough to outflow the cavity in the thermostat housing with the stock parts fully open, much less with my valve. Purely observational, but I'm confident.

I'd also suspect that by removing the coolant flow completely would reduce temps a little more, but likely very minor. The coolant would still be heating up the area, but there isn't much surface area for heat transfer without the trans fluid going into the heat exchanger.
 

crazykid1994

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I kind of wonder what the temp differances might be,if any,between the way CrazyKid and i did the bypass mod,and your thermostat bypass.On paper CrazyKid and i should run cooler,as theoritically there should be more fluid flow to the tranny cooler,plus we've lost one insulating factor with the heat exchanger not blocking airflow to the side of the fluid router.
It's one thing that i've wondered . Crazy Kid i think you should take Caulk up on his offer of a free one,and pop it in,to see if there is any temp differance between full flow,and a slightly restricted flow to the cooler
I'd buy one,but by the time it's sitting on my doorstep,it'd be probably double the cost,aarrgghh,lol.There's times it sucks being a Canuck,lol
I’m to happy with the outcome to pull it apart and change it. Being in south Florida I don’t see much cold weather. If it’s really a huge request to install it I will. In my head I think keeping the heater on the side even with the oil bypassed with caulks plug will still keep temps up since the heater will still warm the metal of the unit from the hot coolant flow and thus heat the oil slightly. Not much since the oil doesn’t stay in the unit for long but still.
Edit: I posted same time as caulk but my thoughts are exactly the same.
 

Wild one

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I don't think the ports in the thermal unit are large enough to outflow the cavity in the thermostat housing with the stock parts fully open, much less with my valve. Purely observational, but I'm confident.

I'd also suspect that by removing the coolant flow completely would reduce temps a little more, but likely very minor. The coolant would still be heating up the area, but there isn't much surface area for heat transfer without the trans fluid going into the heat exchanger.

Yea i'm not sure what the temp differances would be,between unrestricted flow and slightly restricted flow to the cooler.It'd be easy enough to test though,if we can talk Khristopher into taking you up on the offer of a free plug,lol
 

crazykid1994

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Yea i'm not sure what the temp differances would be,between unrestricted flow and slightly restricted flow to the cooler.It'd be easy enough to test though,if we can talk Khristopher into taking you up on the offer of a free plug,lol
Lol. The less I have to get under there the better. I don’t think caulks plug is really much of a restriction. The cavity is very large and by the looks of it caulks plug is not very large.
 

crazykid1994

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@Wild one maybe you can post on Facebook caulks piece and see if anyone may be interested. Or @caulk04 if you have a Facebook go to high performance rams and share your piece
 

Wild one

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@Wild one maybe you can post on Facebook caulks piece and see if anyone may be interested. Or @caulk04 if you have a Facebook go to high performance rams and share your piece

That's beyond my capabilities, i can post my own pics,but have never figured out how to post pics that've been e-mailed to me,lol.
You'd probably have better luck then me Khristopher,as me and a putor don't get along,lol.
 

crazykid1994

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Cool. Got a buddy of mine from Facebook to buy one. Gary. Dude has been waiting to install his rev max kit and I told him to wait for this to hit Facebook because it’ll be faster and easier
 

BlownGP

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For anyone interested, I have some made up and ready to go out. $30 shipped. IMO this is a better option than the Revmax kit and even though they claim the stock cap is prone to breakage so they've made the cap brass, I can't imagine the cap ever breaking as with my part there is less spring pressure on the cap.

PM for info please.

I'll take one.


@Wild one linked me this thread from the ZF fluid thread. Great read and info.

From reading all of this, your products looks like a great upgrade. Coming from RFE with a 180 coolant thremo my trans temps stay low. Sometimes in the summer heat down here in Louisiana the most I've ever seen was 170*.

I'll be getting my first ZF trans Ram soon and I've always read on here that they run hot and it's normal. I always thought it was ********, but now knowing they have the fluid heater installed on them makes sense why everything thinks it's normal.

So with all that said. I like caulk04's bypass and from the looks of it. Works really well.
 
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Bigskyroadglide

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A guy I work with has a 2010 with the RFE trans, says his levels out around 130. Fwiw.

Shifts feel totally normal. I've noticed since I got the truck that is pretty firm for the first few shifts then smooth as butter. Still does the same now.

I watch my gauges like I'm expecting something to blow up, just how I am. I'll continue to monitor as I drive more and certainly report back.

My 11 runs around 120 to 130. Highest I have ever seen my 11 is 165 and that was pulling a 7x14 enclosed tandem trailer with two 900 Harleys inside. It had the stock pan. Now with the extended pan, I rarely see more than 130

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