Transmission Temp

[C Rogers]

I just got a new transmission installed (warranty) on my 2016 Ram 1500 and now the temp gauge reads 244. I'm told by Chrysler that's within the normal range. From what I've read, 195 is within normal and anything over 200 is on the verge of over heating. This was during highway driving and no towing or heavy load involved. Thoughts?

 

[PoMansRam]

I believe 240F is where the fluid starts to deteriorate. Definitely not normal. The coolant 3-way valve and ATF fluid heater on the 8spds try to maintain ~185F. You might see up to 200-210F during extremely hot weather and heavy usage.

 

[Burla]

Not normal, get them on paper, get a reciept that registers your complain, or go to transmisions shop and get them to put something on paper. Make a stink. Anything over 225f is not normal.

 

[crackerjack1957]

Heat take out other trans or was it something else?

 

[pacofortacos]

Ask them what the thermostat temp in the trans is set for.

196 degrees is the temp at which the shutters open to give cooling to the trans cooler, which tells you the control temp FCA wants for normal operation is 195.

 

[PoMansRam]

Ask them what the thermostat temp in the trans is set for.

196 degrees is the temp at which the shutters open to give cooling to the trans cooler, which tells you the control temp FCA wants for normal operation is 195.

Maybe true, but that also depends on what the coolant thermostat is set for.

On the Pentastar Rams, normal coolant temp is in the low 200F range. Same with the engine oil temp. Trans fluid temp tends to hang in the 185F range.

Too damn many temp control devices on our trucks! You've got the shutters, then the T-stat, then the 3-way valve.. then the ATF thermo device.

 

[crash68]

I'm guessing the dealer installed a new transmission but didn't replace the TMU on the side of the trans. Was your old transmission overheating also? if it was the TMU was probably the problem all along.
There is a thermal bypass valve in the TMU that is probably the culprit of the over heating, it send the trans fluid cooler on the top of the AC condenser. The three way in attached to the TMU is what directs coolant to either the TMU or the cab heater core.
240° is not normal, while towing every bit of 8K lbs in 90°F outside, my trans temp will get up to 200°F

 

[PoMansRam]

Just to add to what crash86 said, the nice thing about the coolant 3-way valve is it will throw a code if it's not functioning right. I don't think there is any feedback from the TMU to set a code if there's a problem with it.

 

[ram1500rsm]

Go back to the dealer and tell them you're seeing 240F in your trans temp and that's not not normal, it may be normal for engine oil lol, but not for the trans.
Show this picture to the dealer. That was with 700lbs in the bed and the whole family of 5 inside the truck.

Untitled by RAM RSM, on Flickr

Untitled by RAM RSM, on Flickr

 

[PoMansRam]

The thermal unit on these 8spds is a strange animal. You'd think any type of T-stat would fail in the open position. It seems like the units on our trucks fail closed and won't send any ATF to the cooler in front of the radiator.

 

[69GWC]

Here is mine after 1.5hrs of pulling my 7,000 lb trailer.

 

[pacofortacos]

Maybe true, but that also depends on what the coolant thermostat is set for.

On the Pentastar Rams, normal coolant temp is in the low 200F range. Same with the engine oil temp. Trans fluid temp tends to hang in the 185F range.

Too damn many temp control devices on our trucks! You've got the shutters, then the T-stat, then the 3-way valve.. then the ATF thermo device.

Not really, as the coolant thermostat doesn't have much if any control over the trans temp. The trans cooler up by the radiator is air cooled not coolant cooled and the coolant is used for heating the trans fluid as much or more than for cooling it. The trans temp is controlled by a module on the trans that has it's own thermostat in the module. So if you are running a really cool temp thermostat, the thermostat in the trans module will just stay closed to get the trans fluid temp up. At least as far as I know.
I do know running a 190 stat in place of the 203 had no effect on trans temp on my 2016 hemi.

 

[Sloverado]

Mine stays just under 200 most of the time

 

[C Rogers]

I did get a voicemail from the service advisor from Chrysler who was the one who handled the tranny change. The transmission was changed due to an internal failure. I had the truck in 3 times for hard shifting and they finally changed the tranny but now I have the temp concern and they told me if there is no light on then it's fine. Not sure what else I can do if they say it's fine. I do have a case manager for the original tranny issue but she also said that if there is no indicator light on then it's fine. I told them that everything I read says anything over 200 is too high but my hands are tied. Won't even give me a service appt if no lights are on.

 

[grizzstang]

Dealer assholes, if it were me I would buy the thermostatic control unit and replace it myself. I don't think it is that expensive and certainly cheaper than replacing the trans again (which of course will fail just outside your warranty). If you don't want to tackle it buy the part and take it to your favorite non-dealer tech. There is even a step by step "how to" on this forum somewhere. You are not the first one to have this exact problem and have the dealer deny there is a concern.

 

[gfh77665]

. I told them that everything I read says anything over 200 is too high but my hands are tied. Won't even give me a service appt if no lights are on.

I sympathize with you because of the issues you have had. With that said, can you imagine a world where dealers had to perform endless free services and replacements based "on what people read" on the internet?? They ALL would quickly go out of business. In this case, would 199 be OK but 201 is not because you "read it somewhere"? No, the system can't work that way.

So what to do? The manufactures have to "draw a line" somewhere to indicate where a real problem exists and work is warranted. They do that by having a CEL light up when some parameter is beyond a predetermined set point. They are not trying to burn you. You already got the trans replaced once. That was not free for them by any stretch. If this one is working, then it works.

 

[Burla]

Dealer assholes,

Sadly they keep living up to this designation.

OP if you end up being stuck with this operating tempature, see syn thread for options on fluid. When you run this hot, using a thicker transmision oil would be the same as using a thin fluid with a normal operating temp, and some oils don't break down with heat as well. First, handle this through dealer, then see the fellas in the syn thread who obsess over this stuff.

 

[68PowerWagon]

On the 1500's can you purchase an aftermarket bypass like is available for the 66RFE & 68RFE? This dropped my temps by 25-30 degrees. Something just isn't right with the OP's set up. I personally would do whatever I could to rectify this situation. Written statements from accredited transmission shops, go to another dealer, contact "Ram Cares" on this forum. Do any or all of what I mentioned. That is NOT normal temps!

 

[PoMansRam]

This may have been suggested already, but just ask the folks at ZF is this temp range is OK https://www.zf.com/products/en/cars/products_29289.html

I'd plug in a code reader that can give you ATF temp just to verify as well. If it is indeed 240F+ I think you'll find ZF will say that's a problem.

If the bulk fluid temp is 240F, the hot spots in the transmission are also hotter than they should be.

IMO, run it as is and let this transmission fail under warranty (if there's any left), replace the thermal unit on the trans on your own dime, or trade the truck in and let it be a dealer's problem.

 

[crash68]

On the 1500's can you purchase an aftermarket bypass like is available for the 66RFE & 68RFE? This dropped my temps by 25-30 degrees.

Unfortunately there is nothing readily available on the market just short of having a performance built 8HP70 by Paramount Performance. They offer a 160°F thermal bypass valve but only to the owners of one of their performance transmissions.