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Trans Temp

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Old 07-31-2017, 09:00 PM
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Trans Temp

I have 2008 Ram 2500 4x4, 6.7 with the 6 speed automatic trans. At 70mph the trans temp is 160 degrees. In stop and go it climbs to 180 plus. This seems high to me. I have recently installed a temp sensor so the temps are new to me. Recently towing our fifth wheel up a steep grade the temp climbed to 250. Is this normal or do I need to do something? The truck has 52000 miles on it and is bone stock. Any help would be appreciated.
Old 07-31-2017, 09:19 PM
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The lower temperatures sound right but the 250°f is worrisome. Where is the sensor located and what gear were you in on the steep grade?
Old 08-02-2017, 01:45 PM
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Originally Posted by xcc_rider
The lower temperatures sound right but the 250°f is worrisome. Where is the sensor located and what gear were you in on the steep grade?
The sensor is in the trans cooler line to the cooler. The truck was in 2nd gear I believe. We had climbed the hill before and it had never got that warm.
Old 08-03-2017, 10:10 AM
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I have a 2005 Ram Cummins and I can tell you how my transmission temperatures fluctuate. 160 to 180 highway, 4th gear speeds of 50mph plus is the usual. If you slow down and the torque converter is unlocked those temperatures will go up. The "fluid coupling" rather than a torque converter lock up WILL BUILD HEAT QUICKLY. Reverse gear when trying to park will build heat (no torque converter lockup).

Watch your tach and you can actually see when the torque converter locks up. The tach will suddenly decrease by a couple hundred RPM. This would be like under normal acceleration and after it shifts into the top gear say above 48 MPH, the tack will drop 200 RPM......watch it sometime. You don't even have to be towing to see this. Steady throttle position and then after 48 mph and 4th gear it drops another 200 rpm very soon.

My owners manual stated that towing up steep grades you can push the Tow Haul button, put the shift lever in 2nd gear (at a safe slower speed) and keep your speed above 28/30 mph and the torque converter will lock and stay locked as long as you are above 30 mph. This is very important to know because it will sit there all day and pull without building any additional heat. If the torque converter is not locked temperatures of 250 will come on quick even if it's in second gear. The Tow Haul button tells it I suppose to lock up at that speed.

Another critical piece of information you need to know. If you are pulling a steep grade never pull over and shut the engine down quickly even if things start to get hot. You can pull over of course but leave the engine running with the shift lever in Neutral.....not Park. This will continue circulating the fluid through the cooling system and it will eventually cool down. If you stop and cut the engine off there is no way for the heat to dissipate and the fluid will boil over spilling onto the ground!!! My F250 Ford and I believe my Ram Cummins would not pump fluid in Park........thus the need to leave it in Neutral.

I hope my experiences help you understand what not to do!! My temperature sensor is in the output line of the transmission. I want to see the fluid build heat and know to do something before the entire transmission is scalding hot. Recently while going over Monarch Pass in Colorado (11,340 ft above sea level) I pulled my selector into 2nd and with the tow haul button on I immediately saw a decrease in fluid temperature. I hate getting in stop and go traffic where you inch along at a very slow speed, especially up hill, because there is nothing you can do to force a torque converter lock up. I had a cousin who cooked his transmission while in Colorado going up hill in a construction area for a few miles pulling a very heavy 5th wheel at about 10 mph.
Old 08-03-2017, 02:55 PM
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For the 68rfe there is no difference between P and N. Both pump equally well.
Old 08-08-2017, 01:49 PM
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Originally Posted by Pull Dog
I have a 2005 Ram Cummins and I can tell you how my transmission temperatures fluctuate. 160 to 180 highway, 4th gear speeds of 50mph plus is the usual. If you slow down and the torque converter is unlocked those temperatures will go up. The "fluid coupling" rather than a torque converter lock up WILL BUILD HEAT QUICKLY. Reverse gear when trying to park will build heat (no torque converter lockup).

Watch your tach and you can actually see when the torque converter locks up. The tach will suddenly decrease by a couple hundred RPM. This would be like under normal acceleration and after it shifts into the top gear say above 48 MPH, the tack will drop 200 RPM......watch it sometime. You don't even have to be towing to see this. Steady throttle position and then after 48 mph and 4th gear it drops another 200 rpm very soon.

My owners manual stated that towing up steep grades you can push the Tow Haul button, put the shift lever in 2nd gear (at a safe slower speed) and keep your speed above 28/30 mph and the torque converter will lock and stay locked as long as you are above 30 mph. This is very important to know because it will sit there all day and pull without building any additional heat. If the torque converter is not locked temperatures of 250 will come on quick even if it's in second gear. The Tow Haul button tells it I suppose to lock up at that speed.

Another critical piece of information you need to know. If you are pulling a steep grade never pull over and shut the engine down quickly even if things start to get hot. You can pull over of course but leave the engine running with the shift lever in Neutral.....not Park. This will continue circulating the fluid through the cooling system and it will eventually cool down. If you stop and cut the engine off there is no way for the heat to dissipate and the fluid will boil over spilling onto the ground!!! My F250 Ford and I believe my Ram Cummins would not pump fluid in Park........thus the need to leave it in Neutral.

I hope my experiences help you understand what not to do!! My temperature sensor is in the output line of the transmission. I want to see the fluid build heat and know to do something before the entire transmission is scalding hot. Recently while going over Monarch Pass in Colorado (11,340 ft above sea level) I pulled my selector into 2nd and with the tow haul button on I immediately saw a decrease in fluid temperature. I hate getting in stop and go traffic where you inch along at a very slow speed, especially up hill, because there is nothing you can do to force a torque converter lock up. I had a cousin who cooked his transmission while in Colorado going up hill in a construction area for a few miles pulling a very heavy 5th wheel at about 10 mph.
Thanks! That is helpful information!
Old 08-16-2017, 06:45 PM
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Yes 250 seems high! I have a sensor that is in the tranny pan (mag hytech pan) and I have never gotten above 180 pulling my travel trailer.
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