Normal Transmission Temperature?

[nomad297]

I own a 2004 2500HD Silverado with the 6.0 gas engine. They must have run out of the correct instrument clusters while mine was on the line, so I was blessed with a transmission temperature dummy light instead of an analog gauge.

I recently had to replace my cluster due to lighting and gauge problems, and the new OEM cluster (not rebuilt) came with the transmission temperature gauge. Everything on the new cluster works fine, but I don't know where the needle should rest at cold and where it should hover at normal temperature for the transmission. I've searched the web and read many opinions which vary from 160 to 180 degrees for normal temperature, but that 180 seems too high to me. My 2005 3500HD Duramax's transmission temperature always seems to be around 140 degrees.

I just don't know what it should be. Can somebody please let me know?

Thank you,

Bruce

[CampingN_C_]

Same truck, I can tell you the hottest I've seen mine is right below the 200 mark. That was on flat terrain but about a 95 degree day, pulling 9K lbs. It doesn't redline until upwards of 250, so that tells me where GM feels it's getting too hot.
It seems to average about 100 degrees above outside temp while towing. I don't pay it much attention driving around town.

[RinconVTR]

I am glad someone brought up the fact that most of those ATF charts are old, and outdated. Cause they are. Todays ATF is all synthetic blends or full synthetic and can tolerate much high temps before degrading. And some transmissions are harder on ATF than others, regardless of temps.

Example, I monitored ATF temps of a 2012 Honda Pilot in normal driving and towing at max. Normal everyday drives showed a HUGE variance, from 90f cruising along on the interstate all day, to 210 in rush hour traffic, to 230 (peak) while towing.

Now I own Toyota Sequoia, and per my scan tool, I run 180-200 commonly and I don't see it drop below 170-180 once it reaches this temp. Toyota has a thermostat within the ATF system to keep the temps consistent, and higher than most think it should be. I'm not sure what its set to, but it appears to begin opening around 180.

My main point is temp alone wont tell you if you need to change your ATF sooner than recommended, unless you're well above of any normal temp. IMO, I think 275+ would get my attention and get me to change whatever I'm doing or have the trans looked at.

What's a normal range? I find it varies. I would agree that 275f is high and should raise eyebrows. And I would not worry at all seeing temps hit 230-240 peak (not constant) temps while towing or some other stressful event.

Get a UOA on your ATF to know where you stand and end the guessing game. You may be surprised to learn some transmissions could use a ATF "refresh" (drain 3-4qts and refill) at only 15k.

[Turtle_n_Peeps]

nomad297 wrote:
I own a 2004 2500HD Silverado with the 6.0 gas engine. They must have run out of the correct instrument clusters while mine was on the line, so I was blessed with a transmission temperature dummy light instead of an analog gauge.

I recently had to replace my cluster due to lighting and gauge problems, and the new OEM cluster (not rebuilt) came with the transmission temperature gauge. Everything on the new cluster works fine, but I don't know where the needle should rest at cold and where it should hover at normal temperature for the transmission. I've searched the web and read many opinions which vary from 160 to 180 degrees for normal temperature, but that 180 seems too high to me. My 2005 3500HD Duramax's transmission temperature always seems to be around 140 degrees.

I just don't know what it should be. Can somebody please let me know?

Thank you,

Bruce

Bruce I have to ask why you think 180 it too high? Why not 250 or 150 or whatever? I'm surprised someone hasn't posted the 1970's Tranny chart yet. :R


Here's the deal. Some on this site are living in the days of points and carburetors and 235 is the death knell of transmission fluid.

This isn't 1970 and we don't have points or carburetors or tranny fluid that turns to junk after 235 degrees F. This is a fact and if you think I'm wrong just go to some manufactures sites and see what they say about synesthetic tranny fluids. Or pull a sample and take it you your favorite lab and see what they say about what kind of shape the oil is in.

To answer your question, there is no such thing as a "normal" transmission temp.

If it's cold outside and you aren't towing anything the temp will be low; 140-160 degrees or so? If the outside temp is in the 70's your tranny fluid might be somewhere around 160 to 180? If you are towing up a steep hill with a super heavy load when the outside temp is 100 or more degrees your tranny temp might be 200 to 250 degrees F, or more.

Bottom line is, GM engineers say now days 275 and you should start doing something. The way new trucks are built I can almost guarantee that you will not see 275 unless you are doing something crazy with your truck.

Here is some good reading about miles and tranny fluid.

[Golden_HVAC]

Hi,

140F is way to cold. The problem is any moisture in the fluid will not 'boil off'. At 160F, that is still a little to cold, and is subject to condensation issues. At 180F, all the moisture will be driven out of the transmission fluid, and the fluid will not be overheating either.

At 215F, the transmission fluid is at it's maximum temperature for a 15,000 mile normal service life. It is OK to go a little over 215 - say to 235 on a mountain grade, and still keep the transmission fluid for it's normal 15,000 mile service life, as long as most of the time it is running in the 180 - 215F temperature range, and only reached 235 on a occasional hill climb.

I had a 1985 GM 3500 van based motorhome, and it ran 235F all the time, and was upwards of 255F on a mountain grade. To the point that I had to slow down to keep it from climbing further. That was a 3 speed transmission and 4.10:1 rear axle ratio. It had a 'tiny' transmission cooler, and the engine radiator overheated on a 95F day while driving to Las Vegas, so the engine fan clutch was coming on on flat areas when it was over 95F.

By installing a 11" high and 19" wide transmission cooler with 1/2" tubing behind the radiator, and with the hot trans fluid going into that cooler first, I figured that going into the radiator cooler would 'finish cooling' the fluid, and I got rid of the stock cooler. The next trip, the transmission was not dumping nearly as much heat into the radiator - through it's cooler, however was still running a little to hot. About 200F all the time and warmer on the mountains. So I re-installed the stock factory cooler after the engine radiator cooler, and then the transmission would run between 180 and 185F on level ground (even in 95F weather) and would not go over about 215 on a mountain grade.

I also installed a 'desert cooler' to help control the engine radiator temps. Basically that is some copper tubing run across the radiator, with a small windshield water reservoir and pump and a timer to turn on the pump for 2 seconds at variable internals (from 3 to 30 seconds). On a mountain grade, I would set it to run the pump every 3 or 5 seconds, while on flat lands at 95F outside, I would run it about every 20 seconds to save water while also running the system a little cooler. The evaporating water cools the radiator, A/C condenser, and the transmission coolers too.

Anyway that is my long story.

It is recommended that if you go over 235F, that you change the transmission fluid within the next 1,000 miles. What I would do is remove one of the transmission cooler lines, and then run the engine until all the fluid goes out, and then shut off the engine, drop the pan to get out the last 1/2 gallon or so (without the mess of dropping a pan full of fluid). This gets much of the fluid from the torque converter too.

Have fun camping!

Fred.

[kl1200r]

my 2012 F-350 6.7L normally runs around 110 when it 85 ambient temp

[brirene]

Obviously a different animal, but for comparison mine runs in the 160's empty and 170's-low 180's towing. Usually. If you really want to know what's going on in your engine, get an Edge Insight or Scangauge to monitor that temp, plus a lot more.

[RWDIII]

I don't know about the Chevy gauges,but the
Ford gauges are little better than idiot lights,When I put on the scan gauge
I got a digital readout.
from 180 to 205 the temp gauge never moved off of center.
When I got a new 2015 F250,the first mod I made was to install the scan gauge.

the 250 seems to run 196 vs 191 on the 150 and trans temps seem to be 175 vs 165.
My point is that the stock gauges will show hot only after damage is done,but the scan gauge will show increase degree by degree before stock gauges even move

[TomHaycraft]

Not the same powertrain but hopefully some numbers as general comparison. In my '09 Silverado (with tow package, tranny cooler), 150s to 160s around town and not towing. With the trailer (at 90% of GCWR), not uncommon to run in the 190s, bumping as high as 210 when coming off the interstate and into stop and go traffic until the extra heat load dissipates.

I had a '14 Silverado LT / work truck configuration as a loaner when mine was in the shop a year ago. No tow package or tranny cooler and it ran 195 to 205 around town.

You can find tables with reductions in tranny fluid life as temps increase, seems it didn't really start to fall off until upwards of 250 degrees. I'll have to search again, if i can find, will post a link.

Hope this helps.

[Tiger02]

The temp is going to vary based on the ambient temps. My highest has been 180 going across Texas in 98* temps towing my 5th wheel. With that I've heard anywhere from ambient plus 80 to ambient plus 100, and then again it depends on the transmission and where it was designed to operate.

Hopefully you get enough answers here to get a consensus from others who own a similar truck.

v/r
Vince