Hey guys, i had posted earlier about my trans running too hot! I have an 05 3500 48re. Running around (about 55), my trans temp is around 190 to 200. I stopped and put it in neutral and within 5 minutes it was up to 210. The outside temp was around 92 while i was driving. I just finished replacing the trans cooler and removing the check ball. Unfortunately the problem is still there. Pulling a 9000 lb camper, temps reach 250 and higher. Any ideas on what my next step should be?

 

Turns out the new trans cooler had a place for the thermostat, but no thermostat. Fluid was constantly being bypassed and not cooled. I closed off the bypass and so far, problem seems to be solved! Thanks for all of your replies!

 

Glad you found the problem. Mine runs 100 degrees above ambient outside temp. Will get hotter stop light to stop light. Towing is about the same. 95+ I have to slow down to keep it under 200 when towing. Normal tow speed is about 62-63 mph.

What cooler did you install? and how much cooler is it running.

Dave

 

Im not sure what brand of cooler it is, i picked it up at an auto parts store for about $180. It's supposed to be a stock replacement so i figured everything was right. But it seems to be fine now that the bypass is shut off.

 

Now its running between 165 and 175 with no load about, so roughly about 25 degrees cooler.

 

So the bypass is thermostatically controlled?????

 

The tranny air to fluid cooler in the front of the grill does have a thermostat
in the line. Before that opens and allows flow, the tranny fluid is heated up by a liquid to fluid (heater/cooler) that uses engine coolant. So you might say
the engineers want the fluid at least to engine temp.

I have a picture of the system, since I considered removing the thermostat
in the line that leads to the tranny cooler up front.

Dave

 

Yeah the hot fluid goes into the fluid to fluid cooler first then to the fluid to air cooler up front which has a thermostat on the top drivers side, then back to the tranny.

 

From what i've read, the thermostat is supposed to help cold climate trucks warm up quicker by bypassing the cooler until it reaches a certain temp. They're also bad about sticking. Definately not needed here in nc!