Huxrules
Junior Member
Hello, first time posting to this board, I have a situation that has happened twice now that I think could potentially indicate a failure mode with the 2014 Ram 1500 8 speed transmissions cooling system. I call it a “spike overheat”. What happened to me is that I was driving along I-10 in Texas at 80 mph (the speed limit actually) and the transmission temperatures dramatically began rising. In this case the transmission got to 230F before I found an exit and pulled over. As other posters have noted the solution is to let the vehicle sit and cool and once the transmission gets back to normal operating temps you are fine. I knew this, of course, because I am actually on my second thermostatic valve and transmission oil cooler. I knew also, that once a spike overheat happens that you have broken the thermostatic valve and it will continue to happen until its replaced.
I have had a lot of trouble with the transmission on this truck. It was actually replaced by Ram at 40k (approx) because it was shifting hard, stopped going into reverse, and eventually ended up in “limp mode”. Interestingly I was told by the dealer to let it grenade before sending it in, but thats another story. They did not replace the cooling/heating system (I think). About 10k miles later I was driving my truck on, you guessed it, I-10 going 80 mph when to my horror I looked down and the temperature was 246F. This was near Bandera, I limped it back to Houston with spike overheats occurring probably four more times before getting it to the dealer. At the dealer I was told the bad news, the thermostatic valve had “broken apart” and pieces were in the transmission cooler, potentially blocking flow. Total cost something like 1600$. I fought Ram but caved and had the system replaced. It was fine until three days ago (about 30k later). The exact thing happened, amazingly near bandera/I-20 intersection.
I haven’t taken it to the dealer but it is acting exactly the same as before. My hypothesis is, in this particular failure mode, the thermostatic valve has destructed, the heater doesn’t work at all during warm up, then when its time to actually send transmission oil to the cooler it actually sends it to the heater. The observation that I have had is that the transmission is slow to warm up, taking thirty mins on the highway, the transmission can stay happily around 183-190F on the highway for several hours. The transmission becomes stressed at some point, say climbing hills or traffic and once the temperature reaches 194F, it’s off to the races. With the oil potentially being heated instead of cooled it quickly reaches an overheat (like ten minutes or so).
I think the overarching warning here is to watch your transmission temperatures if you drive on long trips often. Unless you are actually looking at the numbers on the transmission temperature page or the gauge summary page you will not notice it. I’m guessing there are hundreds of ram trucks out there with broken thermostatic valves that spike overheat constantly and the driver is none the wiser. I have yet to see a code or warning light, and the side gauge doesn’t move much, even at 240 deg.
I have no ides what the causes it- I have been driving a lot from Houston to Tucson. This includes a stretch of highway that is 80 mph from Kerrville almost to El Paso. It’s long, like a tank of gas long. By my records the thermostatic valve initial failure happened on the fourth round trip, both times. Causation doesn’t equal correlation, but its suspicious as this stretch of highway is unique to Texas.
I’m going to try to get the transmission to overheat on the highway here by simply running it at a lower gear at speed (like climbing a hill which we don’t have in Houston). It’s probably a bad idea but I’d like to show if its repeatable. Then I’ll take it back to the dealer for a fight.
I have had a lot of trouble with the transmission on this truck. It was actually replaced by Ram at 40k (approx) because it was shifting hard, stopped going into reverse, and eventually ended up in “limp mode”. Interestingly I was told by the dealer to let it grenade before sending it in, but thats another story. They did not replace the cooling/heating system (I think). About 10k miles later I was driving my truck on, you guessed it, I-10 going 80 mph when to my horror I looked down and the temperature was 246F. This was near Bandera, I limped it back to Houston with spike overheats occurring probably four more times before getting it to the dealer. At the dealer I was told the bad news, the thermostatic valve had “broken apart” and pieces were in the transmission cooler, potentially blocking flow. Total cost something like 1600$. I fought Ram but caved and had the system replaced. It was fine until three days ago (about 30k later). The exact thing happened, amazingly near bandera/I-20 intersection.
I haven’t taken it to the dealer but it is acting exactly the same as before. My hypothesis is, in this particular failure mode, the thermostatic valve has destructed, the heater doesn’t work at all during warm up, then when its time to actually send transmission oil to the cooler it actually sends it to the heater. The observation that I have had is that the transmission is slow to warm up, taking thirty mins on the highway, the transmission can stay happily around 183-190F on the highway for several hours. The transmission becomes stressed at some point, say climbing hills or traffic and once the temperature reaches 194F, it’s off to the races. With the oil potentially being heated instead of cooled it quickly reaches an overheat (like ten minutes or so).
I think the overarching warning here is to watch your transmission temperatures if you drive on long trips often. Unless you are actually looking at the numbers on the transmission temperature page or the gauge summary page you will not notice it. I’m guessing there are hundreds of ram trucks out there with broken thermostatic valves that spike overheat constantly and the driver is none the wiser. I have yet to see a code or warning light, and the side gauge doesn’t move much, even at 240 deg.
I have no ides what the causes it- I have been driving a lot from Houston to Tucson. This includes a stretch of highway that is 80 mph from Kerrville almost to El Paso. It’s long, like a tank of gas long. By my records the thermostatic valve initial failure happened on the fourth round trip, both times. Causation doesn’t equal correlation, but its suspicious as this stretch of highway is unique to Texas.
I’m going to try to get the transmission to overheat on the highway here by simply running it at a lower gear at speed (like climbing a hill which we don’t have in Houston). It’s probably a bad idea but I’d like to show if its repeatable. Then I’ll take it back to the dealer for a fight.
