I've been watching my trans temp slowly go up thru the years while towing heavier loads. This weekend I saw it go up (228 degrees) while driving up to Big Bear Lake, Calif. It is a steep climb with slow turns, but truck had no load what so ever, not towing, nothing loaded in bed. The engine temp barley got over halfway. Is it possible for the trans cooling portion of the radiator to become partially blocked? The truck has about 85,000 miles, & coolant color still looks good. I have installed a "mag hy-tec larger pan, and I know an added trans cooler can help, but it seems hard to believe the the trans temp should get that hot without pulling a load. Anyone have any ideas? Thanks in advance, Jim.

 

Sounds like your TC was not locked. This is the primary source of heat creation in an auto tranny. The radiator can become plugged with junk. I would take a peak at that. My suggestion would be to make sure you keep the TC locked by using the Tow/haul to lock up in 3rd and downshifting to 2nd to lock the TC in second. This will keep the temps down.

 

Excellent advice. My 05 will run very cool as long as the torque converter is locked. My temperature guage is in the output line from the transmission so I can see nearly instantaneous heat changes. When running slow enough to prevent lock up my guage will run up to 225 at times if in stop and go or slow traffic on a steep incline for a long period of time. Also while towing uphill below 30 mph it can get very hot. If I follow the owners manual and put it in Tow/Haul, lock it into D-2 and keep the speed over 30 mph it will climb very steep grades for miles on end at 180 degrees. Torque Converter lock up is very important!!

Why don't they put an LED light or some flag on the instrument panel to warn you that the TQ Converter is not locked??? I wonder how a handy guy could wire something up to show lock up or unlock. How about a little yellow LED when it's unlocked to warn you that temperatures will rise if this driving condition continues.

 

Thanks Guys! I seldom (if ever) leave the truck in D2 while pulling and do not always activate the "tow/haul" mode if possible, to keep the rpms down. It sounds like I should be doing so whenever pulling. Any other advice?

 

You only do it when you have too kinda like a manual making sure you are in the right gear for the best
and safest performance. I keep mine in 4th locked up as much as possible but if your MPH drops below 45,
the TC will unlock. This is when you would select the Tow/Haul mode and lock up in 3rd. Get down to 30, go to D2.