Just finished a 8500 K trip and noticed when ever we had little wind coming in the front end this tranny heats up. Highway speeds and warm weather no problem. Cold outside temps and slow lugging tyranny temps rises to 220 to 228 degrees.Tranny cooler is clean and is not leaking (a tranny shop tells me they are prone to cracking).Its as if the fan is not cutting in to pull enough air through to cool the tranny oil and yet the engine temp rises very little!!??Is there no signal from tranny oil to kick in the clutch??

The clutch should kick in if there's enough heat going through the radiator or if the eng gets hot enough. The ECM will kick out OD if the trans gets too hot (or even if it's too cold but that's another subject). Although it was not really that hot according to Dodge's numbers depending on where your taking the reading.Maybe your clutch fan is trying to kick in but has failed. You might check for codes by turning the key on 3 times within 5 seconds and watching the odo for a code. If it has failed then buy a new one ONLY FROM DODGE! None of the aftermarket units work well in our trucks and are nothing but headaches.BTW, where are you taking the temp reading from?

The fan clutch's engagement in your truck is electronically controlled by the ECM. Hot trans temps will cause it to engage. Try looking in between the stack of coolers (it's hard to see so use a flashlight, even during daylight), and see if there is any dirt, leaves, or debris in there.

The fan's action is both thermal and electrically controlled. The fan can engage itself if it feels enough heat or the ECM can engage it.Acceptable levels with modern fluid are much higher than they once were. I suspect the temps were not all that alarming to the truck itself.

ivbinconned wrote:...Cold outside temps and slow lugging tyranny temps rises to 220 to 228 degrees.When going slow, manually select 2nd gear. This will cause the torque convertor to lock when you exceed 25mph (assuming 3.73 axle). If you leave it in drive, the TC doesn't lock until the trans is in 3rd and above 35mph when T/H is enabled. There is also a possibility that the thermostat in the front cooler is gunked up and is reducing flow through the cooler (so it is partially stuck in the bypass position), and that could also cause warmer fluid temps.

228 trans fluid is nothing to be concerned about and the ECM will not turn the fan on for that level of trans temp.

06 Ram (5.9) auto trans cooler and heat?? | Good Sam Community

13 Replies

ScottG
Nomad
Mar 09, 2015
The fan's action is both thermal and electrically controlled. The fan can engage itself if it feels enough heat or the ECM can engage it.
Acceptable levels with modern fluid are much higher than they once were. I suspect the temps were not all that alarming to the truck itself.
ib516
Explorer II
Mar 09, 2015
The fan clutch's engagement in your truck is electronically controlled by the ECM. Hot trans temps will cause it to engage. Try looking in between the stack of coolers (it's hard to see so use a flashlight, even during daylight), and see if there is any dirt, leaves, or debris in there.
ScottG
Nomad
Mar 09, 2015
The clutch should kick in if there's enough heat going through the radiator or if the eng gets hot enough. The ECM will kick out OD if the trans gets too hot (or even if it's too cold but that's another subject). Although it was not really that hot according to Dodge's numbers depending on where your taking the reading.
Maybe your clutch fan is trying to kick in but has failed. You might check for codes by turning the key on 3 times within 5 seconds and watching the odo for a code.
If it has failed then buy a new one ONLY FROM DODGE! None of the aftermarket units work well in our trucks and are nothing but headaches.
BTW, where are you taking the temp reading from?

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06 Ram (5.9) auto trans cooler and heat??

13 Replies

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