8HP70 Transmission Cooler

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AFMoulton

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Has anyone added, or tried to reduce the temps on their 8sp transmission? I have a 2016 5.7 3.21. Just driving on the highway at 80, it was reaching 192*, I know 190* is what Chrysler says the optimum temp should be, but worried if I put 5000-6000 lbs behind it, will I destroy the tranny?
 

Express SN95

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No you won't destroy your transmission. This transmission is meant to run in those temps. This is an example when I had my 5,500lb travel trailer hooked up to my old 2014.

Ramguage2_zpssktohqn9.jpg
 
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AFMoulton

AFMoulton

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No you won't destroy your transmission. This transmission is meant to run in those temps. This is an example when I had my 5,500lb travel trailer hooked up to my old 2014.

Ramguage2_zpssktohqn9.jpg
See I had no load today, and was running 192*, I know they are not all exactly the same.
 

Express SN95

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I'm pretty sure that's ok. If I remember correctly just around town mine averages high 180's low 190's. With the way temps have been lately and 80+mph I can see 192. I personally wouldn't worry about.
 

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The 8HP70 is supposed to run a lot hotter than the 545/65rfe and it's actually to the point where they have installed a heater in the trans pan to warm it up during normal use. You do not need to upgrade the trans cooler even with towing on the 8 speed transmission because of how short the gears are, they don't have to run high rpm and generate a lot of heat like the older transmissions do.
 
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AFMoulton

AFMoulton

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The 8HP70 is supposed to run a lot hotter than the 545/65rfe and it's actually to the point where they have installed a heater in the trans pan to warm it up during normal use. You do not need to upgrade the trans cooler even with towing on the 8 speed transmission because of how short the gears are, they don't have to run high rpm and generate a lot of heat like the older transmissions do.
Would adding a small electric fan on a switch to that part of the cooler/condenser cause any problems? Or could it only help in my peace of mind. Just having a hard time wrapping my head around 190+ temp on a trans. Sorry, new to the Ram world and def new to the 8spd
 

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Would adding a small electric fan on a switch to that part of the cooler/condenser cause any problems? Or could it only help in my peace of mind. Just having a hard time wrapping my head around 190+ temp on a trans. Sorry, new to the Ram world and def new to the 8spd
If it were on my dime, I'd go with an aftermarket high capacity finned transmission pan. You're adding fluid capacity and surface area for cooling in one shot. They are simple, effective, and 100% reliable.

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crash68

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If it were on my dime, I'd go with an aftermarket high capacity finned transmission pan. You're adding fluid capacity and surface area for cooling in one shot. They are simple, effective, and 100% reliable.
The pan on the 8 speed is also the filter and as of now, don't know anyone that makes a replacement pan/filter for it.

Just having a hard time wrapping my head around 190+ temp on a trans. Sorry, new to the Ram world and def new to the 8spd
A member on another forum talked to ZF(manufacturer of the trans) about the temperatures he was seeing, if I remember correctly, 248° was the critical too hot temperature.
 
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AFMoulton

AFMoulton

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https://youtu.be/WI6D1xUOEKQ

So in my research I came across this. Not sure how everyone feels about this guy, but good info nonetheless. He states 215* is the failure temp. I'm going to see about contacting ZF transmission and asking them. It's a stupid long video, but worth the watch.
 

14hemiexpress

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https://youtu.be/WI6D1xUOEKQ

So in my research I came across this. Not sure how everyone feels about this guy, but good info nonetheless. He states 215* is the failure temp. I'm going to see about contacting ZF transmission and asking them. It's a stupid long video, but worth the watch.

Failure temp is fluid specific. Some fluids handle temps differently. In my opinion if your staying in capacity and your trucks under warranty i wouldn't worry about it. Your truck will let you know when it's to hot, and like everyone else has said the 8 speed is designed to run hotter than the 5 and 6 speeds.

I'm also going to add if you put another cooler or something on there you are just giving the dealership/ram something to argue over to try and void your warranty.
 

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AFMoulton,

Today I took note driving around town with almost 90* temps and 55-65mph speed and noted around 190* temps for the transmission. Hopefully that helps give you some piece of mind that this is the normal operating temp for this transmission.
 
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AFMoulton

AFMoulton

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AFMoulton,

Today I took note driving around town with almost 90* temps and 55-65mph speed and noted around 190* temps for the transmission. Hopefully that helps give you some piece of mind that this is the normal operating temp for this transmission.
Thanks for taking a look. The more I research the more it confirms everything that everyone is saying. I may add a small electric fan to that part of the cooler, and put it on a switch, as to me that's cheap insurance.
 

Jerry1984

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I just came back from camping today towing the new travel trailer that weighed probably 6500 loaded and the transmission temps never went above 205 or so up steep long grades. The oil temp on the other hand was way too hot, again. I've had this issue in the past. I wish they used the same style cooler for oil as they do the transmission.a8d027a535b020d2ef4ba90dce0478bc.jpg
 
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AFMoulton

AFMoulton

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I just came back from camping today towing the new travel trailer that weighed probably 6500 loaded and the transmission temps never went above 205 or so up steep long grades. The oil temp on the other hand was way too hot, again. I've had this issue in the past. I wish they used the same style cooler for oil as they do the transmission.a8d027a535b020d2ef4ba90dce0478bc.jpg


Jerry, you are here in Idaho right? I'm down in Mountain Home, and the drive from Idaho Falls to MoHo yesterday got me really watching the temps on the tranny and oil. I'm going to add a small electric fan to help me be at peace with the trans temp, and maybe an aftermarket oil cooler. Looking at a camper same size as yours.
 

Jerry1984

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Jerry, you are here in Idaho right? I'm down in Mountain Home, and the drive from Idaho Falls to MoHo yesterday got me really watching the temps on the tranny and oil. I'm going to add a small electric fan to help me be at peace with the trans temp, and maybe an aftermarket oil cooler. Looking at a camper same size as yours.



Yes sir. Live in meridian, but we went camping between pine and featherville. From the pilot station to the left turn at the huge tent is where mine heated up. Not where I usually camp but went with some friends that live in mountain home.
Have towed to salt lake before and I swear from mountain home to near the turn for Idaho falls there are always mean winds that kill mpgs.
 
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AFMoulton

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Yes sir. Live in meridian, but we went camping between pine and featherville. From the pilot station to the left turn at the huge tent is where mine heated up. Not where I usually camp but went with some friends that live in mountain home.
Have towed to salt lake before and I swear from mountain home to near the turn for Idaho falls there are always mean winds that kill mpgs.
What model Coleman is that?

I know exactly where you are talking about in the Pine/Featherville area! Beautiful! But you are right, that first few miles up into the mountains is a haul, and way uphill!
 

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on the return part of my trip (2200 miles) my speeds in Montana ranged from 75 to 90mph and with the R/T the highest temps I saw were coolant 204, oil 220 and the tranny 188. I am guessing those numbers fall within spec. Happy trails to anyone hitting the highway this summer.
 

Jerry1984

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What model Coleman is that?

I know exactly where you are talking about in the Pine/Featherville area! Beautiful! But you are right, that first few miles up into the mountains is a haul, and way uphill!



262bh. Weather was about perfect this weekend. Could have been a few degrees warmer but overall pretty great.
 

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Would adding a small electric fan on a switch to that part of the cooler/condenser cause any problems? Or could it only help in my peace of mind. Just having a hard time wrapping my head around 190+ temp on a trans. Sorry, new to the Ram world and def new to the 8spd

Snoop around Allpar.com for this transmission. As I remember RAM engineers designed an elaborate thermo system for the ZF tranny. In part, the thermo system was designed to get the tranny temperatures up to operating temperature as soon as possible due to the maximum lubrication properties of the transmission fluids, this offers better MPG's.

I would first check with your dealer to see what the in-spec operating temperatures are.

Here is a good read.
Engineering Ram’s leading-edge driveline - SAE International
 

TexasRam2016

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New 2016 1500 with the hemi and 8 speed. My transmission temperature is as the op. About 190ish just cruising with no load and I have the 3.21 gears.
 
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