8hp70 heater bypass

[caulk04]

Glad to hear that! At the moment I have only two made, one is in my truck and the other is going to crazykid when I return his thermostat. I understand he doesn't exactly have a use for it, but I told him I'd give him one anyway.

I'll knock out a few more at work next week, should have no problem squeezing in on the lathe after hours. I'm thinking $30 shipped, hopefully that's allowed by the forum here.

 

[chrisbh17]

Glad to hear that! At the moment I have only two made, one is in my truck and the other is going to crazykid when I return his thermostat. I understand he doesn't exactly have a use for it, but I told him I'd give him one anyway.

I'll knock out a few more at work next week, should have no problem squeezing in on the lathe after hours. I'm thinking $30 shipped, hopefully that's allowed by the forum here.

Sending you a PM.

 

[crazykid1994]

Glad to hear that! At the moment I have only two made, one is in my truck and the other is going to crazykid when I return his thermostat. I understand he doesn't exactly have a use for it, but I told him I'd give him one anyway.

I'll knock out a few more at work next week, should have no problem squeezing in on the lathe after hours. I'm thinking $30 shipped, hopefully that's allowed by the forum here.

You can sell the one you are planning on sending me. Also, I don’t need the thermostat back, you can just toss it. Save your money. I have no use for it since I cannot reinstall it and a new thermal unit comes with a thermostat if I wish to return to stock. I’m super curious what temps you’ll see with warmer temps. The grill shutters definitely seem to be keeping your trans temps a bit higher it seems. Ambient temps in the 20s and still reaching 117.

 

[Wild one]

More data for yinz.

This is at the end of my normal drive to work, plus a couple miles then back home a couple hours later. 24miles each way, 60mph cruising, back road ish. Normally the trans is 165 by this point, levels out at 176 if I drive a little further.

The PCM seems to keep the grille shutters closed to warm up the trans, then opens it if the coolant crosses 203-205. The trans levels out here at 110-115 and the coolant settles down as well, seems the PCM is ok with the trans at this temp and stops trying to force it hotter with the shutters.

I'm quite happy with it as is. There is nothing wrong, in my mind, with the trans running at this temp and I can only assume it'll be a little warmer once temps return to a hospitable level.

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I don't suppose you've layed into the throttle hard a couple times in row have you.It's -40 here so mines parked,but i'd like to see what happens to the temp with a couple back to back hard acceleration pulls from a stop or a slow roll up to 65 mph or higher.

 

[caulk04]

You can sell the one you are planning on sending me. Also, I don’t need the thermostat back, you can just toss it. Save your money. I have no use for it since I cannot reinstall it and a new thermal unit comes with a thermostat if I wish to return to stock. I’m super curious what temps you’ll see with warmer temps. The grill shutters definitely seem to be keeping your trans temps a bit higher it seems. Ambient temps in the 20s and still reaching 117.

If you insist, thanks!

I don't suppose you've layed into the throttle hard a couple times in row have you.It's -40 here so mines parked,but i'd like to see what happens to the temp with a couple back to back hard acceleration pulls from a stop or a slow roll up to 65 mph or higher.

I haven't yet, but I certainly can. I'll post back

 

[caulk04]

As you's request.

Tried to take a video, but hit the wrong button of course. Instead got two pics, before and after a slight uphill pull from 65 to whatever it shuts off at (105?). The shutters were obviously still closed or mostly closed since the coolant temp rose like it did, but the trans climbed immediately then slowly dropped a few degrees the last two miles to home.

I wonder where the temp sensor is in the fluid path...

 

[Wild one]

As you's request.

Tried to take a video, but hit the wrong button of course. Instead got two pics, before and after a slight uphill pull from 65 to whatever it shuts off at (105?). The shutters were obviously still closed or mostly closed since the coolant temp rose like it did, but the trans climbed immediately then slowly dropped a few degrees the last two miles to home.

I wonder where the temp sensor is in the fluid path...

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I wasn't expecting you to wind it out to wide open,lol.But thank-you for that test.Hows the shifts feel under full throttle

 

[Different Drummer]

I will be curious to see what the Trans. Temp. does over a longer run time / distance and higher ambient Temps.
It takes my transmission over 25 miles to get into the high 170's F at ambient Temps in the 40's.
I am not sure I want my Trans. running routinely below 120F. I would love to see 150F though.

 

[Musky Mike]

That looks great, you did an awesome job. I'm looking for a 20-30 degree reduction in temp, but being able to quickly and easily return to stock (I have an extended warranty). I would like to purchase one if it works out.

Testing is looking good. PM sent.

 

[caulk04]

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.

 

[Wild one]

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.

You and me both,i watch the gauges in my truck like a hawk,lol.I'm not to worried about the tranny running to cold,as long as it gets over a 100F,i think it's perfectly fine.In the old days we used to hang the biggest coolers we could get behind the grill for the trannies and were happy as hell if we could get the tranny down to 110F.The 8 speed is slightly differant,but it still uses clutches and planataries same as the old 3 speeds did,and clutch facings definitely last longer the cooler they run.The tranny will be engineered to survive at -20 while being beat on.The oil patch is hard on things,and they don't seem to be able to kill the 8 speed in cold weather,neither does my neighbour,he starts his truck at -20 ,and it's lucky to run 2 minutes before he's flooring it,leaving his house,and he's got 180,000 clics on his 8 speed now,lol

 

[crazykid1994]

I will be curious to see what the Trans. Temp. does over a longer run time / distance and higher ambient Temps.
It takes my transmission over 25 miles to get into the high 170's F at ambient Temps in the 40's.
I am not sure I want my Trans. running routinely below 120F. I would love to see 150F though.

https://www.ramforum.com/threads/revmax-8-speed-thermostat-bypass.171776/page-36#post-2439178

 

[Different Drummer]

You and me both,i watch the gauges in my truck like a hawk,lol.I'm not to worried about the tranny running to cold,as long as it gets over a 100F,i think it's perfectly fine.In the old days we used to hang the biggest coolers we could get behind the grill for the trannies and were happy as hell if we could get the tranny down to 110F.The 8 speed is slightly differant,but it still uses clutches and planataries same as the old 3 speeds did,and clutch facings definitely last longer the cooler they run.The tranny will be engineered to survive at -20 while being beat on.The oil patch is hard on things,and they don't seem to be able to kill the 8 speed in cold weather,neither does my neighbour,he starts his truck at -20 ,and it's lucky to run 2 minutes before he's flooring it,leaving his house,and he's got 180,000 clics on his 8 speed now,lol

I hear you on the Temps. Under just about any circumstance when dealing with anything mechanical the operating Temps. are an important consideration. Heat and contamination to me are our two largest concerns.
However, I can't say just yet that I agree 100%. If I was dealing with the THM 400 in my one ton GMC I would say the lower the Temp.the better. And yes, I do have a monster cooler on it that is plumbed so it is on the down side of the integrated cooler in the radiator. And the radiator is an aluminum large heat busting design. I will never worry about getting that transmission too cool.
On the other hand I just have a wishy-washy gut feeling that the ZF 8 speed is lives off in an engineering world of it's own. To make things worse everything gets shrouded in general statements or total lack of transparency. i.e. " it is operating within design parameters". Or the fact that we cannot get any rock solid information on what supposedly makes the ZF Lifeguard 8 fluid such a magical potion for the transmission. Also, everything seems so integrated with one system dependent upon what another is doing or experiencing. All of it being fed into the computer which shouts out commands to all systems. Just my cautious nature I guess. Also, folks like me are not putting the demands on the equipment like you and Crazykid are.
I spend hours droning down the highway at speeds often sustained at 80 MPH. 75 MPH is very common but no sudden full throttle acceleration through the full range of gears or towing.
I like Caulks device a lot and it is almost exactly what I was trying to come up with. I hope he gets a chance to run it in a more extended manner above what is his normal commute to work.
Also in warmer ambient Temps.
Time will tell I guess.

 

[Different Drummer]

https://www.ramforum.com/threads/revmax-8-speed-thermostat-bypass.171776/page-36#post-2439178

Thanks for the link. This topic has gotten pretty long and though I had read those posts I had forgotten that information.
Even your friend "Mike" is seeing 140's and you mention that the cars are 160 - 170. I think yours after modifying was high 120's.
Right at this very moment, any of those numbers I could live with with. But getting down into the 100-120 range I still have to wonder how those numbers play out in regards to the "Big Picture" of integrated systems all reporting to the main Onboard computer and how one interacts or effects the others. For the time being at least. Not to mention any engineering considerations with the ZF 8 Tranny.
Theory is good but field testing supports or shoots down the theory. A moderate improvement in this case gets my 100% endorsement. A major change in Temps. keeps me in the guardedly optimistic camp.
You guys are essentially Beta testers and I applaud you for that. You are more adventurous and aggressive than me. Maybe it is an age thing. I seem to have gotten less cavalier in recent years.

 

[Wild one]

The one test i am waiting for is Ed's test on the fluids expansion rate,as that'll give a little more data on things.If the fluid doesn't expand much after 120F ,i think the lower temps won't be a big issue.I'm kicking my rear for not doing that test last summer when i did the last fluid swap on mine,as now i'm curious on how much the fluid volumne changes from cold to hot.

 

[crazykid1994]

The one test i am waiting for is Ed's test on the fluids expansion rate,as that'll give a little more data on things.If the fluid doesn't expand much after 120F ,i think the lower temps won't be a big issue.I'm kicking my rear for not doing that test last summer when i did the last fluid swap on mine,as now i'm curious on how much the fluid volumne changes from cold to hot.

With the ppe pan I think that’ll also change the fluid levels under expansion as well. 2 extra quarts of fluid. Guess I’ll spring for that before long tubes. You would think they would have to account for hot and cold fluid levels otherwise all the people in the frigid north who have short drives would end up with transmission failures from fluid being to low. If I had a measuring beaker I could test new fluid expansion rates since I have 1.5 qts of fluid sitting on my shelf.

 

[Wild one]

With the ppe pan I think that’ll also change the fluid levels under expansion as well. 2 extra quarts of fluid. Guess I’ll spring for that before long tubes. You would think they would have to account for hot and cold fluid levels otherwise all the people in the frigid north who have short drives would end up with transmission failures from fluid being to low. If I had a measuring beaker I could test new fluid expansion rates since I have 1.5 qts of fluid sitting on my shelf.

You can substitute a glass measuring cup ,just don't let the wife catch you using her good glass measuring cup,lol

 

[caulk04]

Cold this morning, still made it to a reasonable temp on the ride in. Clearly still in what Dodge thinks is an acceptable range.

 

[crazykid1994]

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Cold this morning, still made it to a reasonable temp on the ride in. Clearly still in what Dodge thinks is an acceptable range.

That’s lower than anything I’ve seen but granted my lowest temp this year was 37° and I hadn’t done the heater delete yet. gotta love Florida.

 

[EdGs]

You can substitute a glass measuring cup ,just don't let the wife catch you using her good glass measuring cup,lol

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