Trans running hot on 2005Ram 3500 Auto

There is no third on the selector. 1-2-od. The more you can keep the TC locked the cooler it will run.

Cummins12V98 wrote:
Run 3rd gear when climbing. RPM's higher is better with the 48 trans if you are towing very heavy.

That's what I do. My Daddy always told me that's what they put a transmission in a truck for. Auto transmission selector lever works wonderfully for me.

Run 3rd gear when climbing. RPM's higher is better with the 48 trans if you are towing very heavy.

I believe your truck will go into limp mode with tranny temps around 265 degrees F. My 2006 diesel RAM w/auto tranny had an Edge monitor on it that would alarm at 230 degrees F. I have hit the 230's a couple times and 240 once. Used to make me worry until I found out the limp mode number of 265.

Make sure they put the right fluid in the transmission when it was serviced. It requires AT+4 synthetic fluid. I have run mine with the gauge peg past 285* for 12 miles, long story, had no other choice. Fluid never showed any discoloration. My temperature sensor was located on the cooler output line from the transmission.

"I'm going to make many assumptions on this issue.

I'm going to assume you are pulling the temperature from the OBD2 port, not the cooler line (hotter), and not the pan (cooler).
I'm going to assume that you do have the T/H enabled.

For all other replies; the '05 transmission T/H mode does NOT lock out overdrive. It does lock the TC in 3rd and at a lower speed in 4th.

freddmc, at what speed are you towing? If you are in hilly winding terrain if you slow down slightly the trans will hold 3rd longer. If you are powering hard out of a turn the TC will wait longer to lock up in 3rd, just ease up to about 20% throttle position then get back on it and the TC will hold."


Yes, you are correct,,I have a cts gauge off the obd2 port and we do have T/H enabled. This happened to my daughter last summer towing in hot weather in the mountains and she would have been travelling at 60. Other than in that I am sure she would have just kept her foot on the throttle and let the truck downshift automatically. So I am trying to get enough information to advise her what to do. I have been involved with cars/trucks/race cars for so long that I instintively know what to do in situations like that but its difficult for young people without that kind of experience.. Prior to the trip I had the trans serviced with a fluid change and band adjustment(not sure if it needed adjustment but it was at the dealer).Since then we put approx 8000 miles on it (just around town stuff)and the fluid is now discolored so the assumption is it got too hot and my daughter did say the CTS alarm went off(its set at 230) I was told on another forum that even in t/h mode and downshifting it is difficult to hold it in 3rd and t/c lockup.
I will look at the cooler bypass issue.
The option to have the TSB flashed is interesting as it will enable you to lockout OD thus keeping it in 3rd. What would be the downside to this option?

Thanks for all the replies.

Regards

Fred

I'm going to make many assumptions on this issue.

"I'm going to assume you are pulling the temperature from the OBD2 port, not the cooler line (hotter), and not the pan (cooler).
I'm going to assume that you do have the T/H enabled.

For all other replies; the '05 transmission T/H mode does NOT lock out overdrive. It does lock the TC in 3rd and at a lower speed in 4th.

freddmc, at what speed are you towing? If you are in hilly winding terrain if you slow down slightly the trans will hold 3rd longer. If you are powering hard out of a turn the TC will wait longer to lock up in 3rd, just ease up to about 20% throttle position then get back on it and the TC will hold."
Yes, you are correct,,I have a cts gauge off the obd2 port and we do have T/H enabled. This happened to my daughter last summer towing in hot weather in the mountains and she would have been travelling at 60. Other than in that I am sure she would have just kept her foot on the throttle and let the truck downshift automatically. So I am trying to get enough information to advise her what to do. I have been involved with cars/trucks/race cars for so long that I instintively know what to do in situations like that but its difficult for young people without that kind of experience.. Prior to the trip I had the trans serviced with a fluid change and band adjustment(not sure if it needed adjustment but it was at the dealer).Since then we put approx 8000 miles on it (just around town stuff)and the fluid is now discolored so the assumption is it got too hot and my daughter did say the CTS alarm went off(its set at 230) I was told on another forum that even in t/h mode and downshifting it is difficult to hold it in 3rd and t/c lockup.
I will look at the cooler bypass issue.
The option to have the TSB flashed is interesting as it will enable you to lockout OD thus keeping it in 3rd. What would be the downside to this option?

Thanks for all the replies.

Regards

Fred

Down-shifting is the usual means to running engine/transmissions cooler when climbing mountains. Good luck.

I'm going to make many assumptions on this issue.

I'm going to assume you are pulling the temperature from the OBD2 port, not the cooler line (hotter), and not the pan (cooler).
I'm going to assume that you do have the T/H enabled.

For all other replies; the '05 transmission T/H mode does NOT lock out overdrive. It does lock the TC in 3rd and at a lower speed in 4th.

freddmc, at what speed are you towing? If you are in hilly winding terrain if you slow down slightly the trans will hold 3rd longer. If you are powering hard out of a turn the TC will wait longer to lock up in 3rd, just ease up to about 20% throttle position then get back on it and the TC will hold.

But with all that being said, I doubt it is your driving style. I'm betting that your cooler thermostat is stuck in bypass mode and causing the warmer temps (especially since it is currently winter time).

Pop the hood and you have easy access to the secondary cooler (which is not part of the radiator). Read the very first post in the link below about how to access and remove the thermostat.
CumminsForum 3rd Gen Trans T-Stat

Is the 230 temp of the fluid in the tranny pan or the output line? Sounds like your torque converter may not be staying locked. I have a probe in both my output line and in the pan and the pan temps hardly rise above 140! Above 235 in the pan is not good for extended times.

Chris