68RFE Trans - Getting Hot In Park Or Neutral?

[Tonybain42]

Hello all, I have a 14 RAM 2500 with a built-in transmission by Redline performance diesel, the trans thermostat delete, running a RaceME Ultra with tuning from DRD.

The trans and thermostat delete has been in the truck since 2020 and has about 60k miles on it.

Recently, I noticed my trans temperature is higher than it used to be.

I started noticing this last summer.

The other day, I was sitting in a parking lot eating for 15-20 min and noticed the trans temp peaked at 204 degrees just sitting there.

I have tried park and sitting in neutral to see if that made a difference, and they seem to be the same.

I also added some fans to the factory trans cooler, thinking my electronic fan clutch could go out, but that doesn't seem to be the case.

I have a 180 thermostat in the engine, and the coolant temp is usually 183. Any ideas on what could be making the trans heat up while not moving?

While driving, it also seems to run warmer than it did a year or two ago.

I remember it would rarely get over 140-150; now, it's generally around 167 when I've been driving for a while, and it stays there.

 0 Comment(s)

[AK Bob]

Hello all, I have a 14 RAM 2500 with a built-in transmission by Redline performance diesel, the trans thermostat delete, running a RaceME Ultra with tuning from DRD.

The trans and thermostat delete has been in the truck since 2020 and has about 60k miles on it.

Recently, I noticed my trans temperature is higher than it used to be.

I started noticing this last summer.

The other day, I was sitting in a parking lot eating for 15-20 min and noticed the trans temp peaked at 204 degrees just sitting there.

I have tried park and sitting in neutral to see if that made a difference, and they seem to be the same.

I also added some fans to the factory trans cooler, thinking my electronic fan clutch could go out, but that doesn't seem to be the case.

I have a 180 thermostat in the engine, and the coolant temp is usually 183. Any ideas on what could be making the trans heat up while not moving?

While driving, it also seems to run warmer than it did a year or two ago.

I remember it would rarely get over 140-150; now, it's generally around 167 when I've been driving for a while, and it stays there.

Check your transmission oil cooler for possible air flow blockage.

 0 Comment(s)

[Tonybain42]

The transmission oil cooler is completely clean externally.

I even added two pusher fans to increase airflow across the cooler.

 0 Comment(s)

[Tonybain42]

Does anyone have any other ideas about this?

Just yesterday, driving trans was 150ish; I stopped to eat and sat in the parking lot for 15 min; not moving in the park, it went up to 172.

 0 Comment(s)

[sootmaster]

External inspection is good for bugs and grass, but the FLOW test is the amount of fluid flowing through the cooler (suspect pancake stock cooler), which is a different test.

Pancakes have waffles-style chambers, mostly clogged with TQ material from the lockup clutch.

Disconnect the lines to cooler and BACK flow with air and a rag to see if anything comes out, then re-evaluate what is present, if any.

If you have access, you can feel across the trans cooler to see if any part is cooler, like partially restricted.

An external gauge or other thermistor tests for bias, but the internal trans sensor is degrading.

Wiring checks to and from trans inspection for corroded connections or water intrusion.

Test to ensure it is happening in real-time and not a ghost from the degraded sensor.

I would let it sit overnight and look at the outside air temperature for engine PID, the evaporator temp sensor, the coolant sensor, and trans to see if any are way off.

Thermistors degrade over time.

It might need 24 hours plus soak time to ensure a steady temperature of fluids or air.

It is best at night without sunlight, which may influence your readings.

 0 Comment(s)

[Tonybain42]

Thanks for the response, Sootmaster.

I know the sensors are correct because when I start the truck in the morning, they all match ambient temp and rise as temp increases and falls when driving.

It's so weird to me that it heats up sitting in park, but cools down from that when I'm driving.

I haven't disconnected the cooler to blow it out or anything.

That's my last resort.

 0 Comment(s)

[KJC]

In my opinion, what you are seeing is normal and nothing to worry about, I'm guessing it's been pretty warm in LA, LOL!

Trans will heat up just sitting without any airflow across the cooler.

My truck runs right at 168 while driving.

I wouldn't worry about anything unless you see sustained temps over 200 while driving.

 0 Comment(s)

[sootmaster]

Thermistor checking is checking that two or three are near or the same.

AC evaporator sensor can read more or less than actual, but let's say it is 10* degrees cooler than actual, then raise and fall, but the air will be 10* hotter due to cooler at the starting point.

It can also be hotter than actual.

Since you placed fans on the cooler and additional airflow at the stop, it should have helped!

Dodge has a spec for fluid out of the cooler for a given period to test the flow of the cooler circuit.

If you feel the sensor checks are ok, then some other possible.

If you used the same external cooler and radiator tank cooler when the new transmission was, I would not have advised this as you need a hot flush machine to clean these coolers.

Pancake and radiator internal tank.

I always replace all coolers and thermal bypasses with high-value repairs.

You ask for failures like using an old radiator and hoses with a new engine.

Second, if trans cooler lines are still going through the radiator tank cooler, an additional heat source is also needed.

The lower radiator tank and the hose will be the same as the block at an average temperature.

If you're not in an environment of snow and ice, there's no need for these radiator tank cooler to warm cold fluid, but this style of bronze screen pack can also hold the last trans material, causing reduced flow and dirt.

The fluid flow test is done in a container, the amount of fluid is measured, and then an air test is performed for the material.

I run off the case to my external cooler (tube style), not a pancake.

Cooler Tubes are as large as the inside of the cooler lines, so there are no restrictions.

The cooler is large enough so fluid will cool from the inlet drop to the exit, but it will still have great flow.

I would love to have it as close to the outside temperature as possible, showing the heat load is expelled from towing and driving, given your specs of what you would like it to be!!

These tests will narrow down the ifs of passable faults.

I would consider right after hi-way and then sitting right off for a spike in temperature from built-up heat from driving, but not steady standing temperature over a long period.

Viscus fluid heat can be built by slipping parts and dragging in the input to the TQ stator in park, but it is normal for the cooler to expel out.

Painted trans-cases hold in heat as bare trans-cases are free of mud and dirt, which will be far better cooled.

Looking closely, you will notice that most manufacturers no longer paint AC condensers!

Painting reduces the efficiency of releasing heat into the air.

You must modify it to the best you see fit, as these are only suggestions.

Sent from my E7110 using Tapatalk

 0 Comment(s)