Question About 6/speed Automatic Temps

[Pool Runner]

My '08 2500 will get as high as 180 degrees according to the stock info display. In the winter it stays around 140-145 and will only get as high as 160 ish if I'm heavy that day. I was wondering what was normal temps for the 6.0L/ 6-Speed combo. At what temp do you worry at?

[96chevy7.4L]

Anything over 200 and I would drop the fluid out and refill. 180 -190 is okay. Not necessarily change the filter after a trip over 200 but atleast the fluid. Transmission fluid does not do well over 200 degrees.

[Shatterz]

If my memory serves me correctly the manual states that normal operating temps are between 160-180. I think the highest I've ever seen mine is about 170. For me Normal winter time temps are usually between 110-120 and summertime between 150-170. IMO I would not want to see anything over 200F, you are really starting to cook the fluid at that point. The stock trans coolers on these trucks are OK. If you start heavy hauling a bigger cooler should be the first thing on your list.

[Pool Runner]

Ok so yesterday temps were 96 degrees. I had a lot of stop & go errands to run, I was easy on my truck for the most part nut at the hottest point of the day my trans temp in the dic readout read 198. You guys said that the trans fluid is no good at 200 degrees. Why doesn't a warning light come on when it gets this hot. Anyone have any reccomendations on tranny cooler upgrades? My local mechanic quoted me about $500 to install a frame rail mounted extra cooler with a fan that can be triggered by a thermostat. Is this worth the money? or will it only slightly drop temps.

[jandersinc]

If I remember correctly you'll get a warning or trans over temp message when the trans fluid hits about 260 F. I saw that posted on here somewhere awhile back.

 

Highest I've ever seen was about 165 and that was driving a few miles up a steep logging road in 4wd on a 70 degree day.

 

Not sure why it waits until 260 to warn you unless trans fluid is actually good up to that temp.

[hockeypro1411]

Yea I'd say the 200 degree thing might be a little bit old-school. Of course you don't want to be driving around with burnt fluid, but 200 seems a little low.

 

And an extra transmission cooler isn't hard at all to install yourself. They can be found online for at or under $200 for a pretty decent one. I wouldn't bother with a fan and thermostat. I'd just mount it in place of the factory one and leave it be.

[dillon]

generally speaking at 250* the oil will start to break down and the additives will start to cook off. If any oil hits that temp it becomes about useless(its cooked down to the base mineral oil stock). As far as running temps go, if i remember right from school we talked about 180* being the optimum and 200* being the highest you want to see for continuos running.

[TyeeMan]

If it's in the 90's and I'm in stop and go traffic or doing a bunch of errands and not getting a lot of air past the tranny cooler my tranny in my 1500 HD will approach 200. Keep in mind that the tranny fluid goes through the tranny cooler, but it also goes through a cooler in the radiator. What temp is the average thermostat/coolant in a modern day vehicle?? About 195 degrees. So if your not passing a lot of air past over the tranny cooler, , , your going to heat up the tranny oil just by going through the radiator. That and your tranny genereates more heat running the gears than it does running down the highway once the torque converter locks up and/or your in over drive.

200 degrees is 200 degrees, but in my opinion there is a difference if the heat is generated by the tranny fluid passing through the radiator, or the shear forces of a tranny pulling a heavy load which heats up the fluid.

Do yourself a favor and run pure synthetic tranny fluid, it can handle the higher temps a lot better.

[TorkFaze]

Factory dexron VI is better than the old dexIII stuff.

 

Changing fluid because it hit 200F once is a HUGE waste of money. We run our testers VERY HARD when we're towing and the trucks see higher than that regularly and don't run back and change fluid. We've occasionally tested fluid samples after running them hard and have not seen problems.

 

I agree that if you spend LOTS of time at hot temps, your fluild degrades sooner, and the hotter the temp, the quicker it degrades, but at 200F, it's the coolest liquid in the truck except for washer solvent!

 

A typical thermostat opens at a coolant temp 195 and usually runs hotter than 200 when AC is on and you're working the truck. Engine oil is at or above coolant. Axle fluid when towing gets warmer than you might think.

 

Touching 200F occasionally is a "so what" with the 6-speed running Dex VI.

 

The 6-speed will go into a protection mode if you get too hot. You'll get a warning on the DIC.

 

My personal opinion NOT based on any data from my day job......If you see the DIC warning, change your fluid as soon as it's convenient. Also personal opinion.....If the 6-speed running DexVI spends more than about half the time above 210f or so, I'd consider using the 'severe' duty cycle for fluid changes in the owner's manual. From memory, that's a 50K mile fluid change interval instead of 100K+.

 

TF