Transmission Fluid Temperature

[Frankly]

We just got back from a 6300 mile trip that took us west from Alabama to Colorado Springs, Las Vegas, Los Angeles, San Francisco, Jackson, Yellowstone, Rapid City and back home. Went through several mountain passes, and saw transmission fluid temps hit 250 F several times. The last pass we went up on Hwy 14 near Sheridan Wyoming was by far the most difficult and I had to stop several times going up to allow things to cool down. I refused to allow the transmission to get above 250 or the radiator temp to exceed 225 F. I was really flying blind coming out of Yellowstone, because we had no cell data and I could not solicit the internet for the best route. I chose Hwy 14 over Hwy 26 and that was probably the wrong choice?

So the question I have is 250 F to hot for transmission fluid, and should I change it out now that I'm home and out of the mountains? It still has a pink tint, but not as pink as is was before we left.

[falconbrother]

lawrosa wrote:

falconbrother wrote:
I would just do a drain and fill to be safe. I do drain and fills a lot. Takes five minutes and 3.5 quarts of Dex6. If you have to pull the pan it takes considerably longer but, still not a hard job, just messy. If you have to pull the pan put out some cardboard to catch the mess.

On my 4L60e I ground the head of the drain plug off and welded an 11/16 nut in it's place. Plug comes right out. Literally takes five minutes to do the job.

Is that what yours takes? My manual states 5 quarts. But thats with filter changes. I have the 4l60e.

So if I just pull the plug and drain im looking at 3.5 qt?

On mine it depends. If I do a full filter change it's about 5 quarts. For a simple drain and fill it's 3.5-ish. I do drain and fills like every 3 months, with the oil change so the fluid stays fresh. I did a filter change in February and two drain and fills since then. Of course I use store brand Dex-6. If it were really difficult to do a change and I wasn't going to do it very often I'd use super duper synthetic fluid. Best to start a little low and top up. Don't risk over filling! Lord have mercy..

[DinTulsa]

Different vehicles have different Trans temps. My 2006 ram 2500 would never get over 180, my 2012 f250 runs around 210 pulling all day long. But, I would change the fluid if it hit 250 for any length of time. It's cheap insurance to keep the trans healthy.

[time2roll]

Frankly wrote:
The temperatures were measured off the OBD2 with a scan gauge. Not sure how accurate these OEM sensors are, but it sure beats looking at the idiot gauges, which show very little if any change.

The gauge does move. You were still mostly in the normal zone so it does not move much if at all.


http://www.intellidog.com/dieselmann/b_smoke13.htm

You may disagree with what the OEM engineers call normal. And I agree it will tend to give less warning as you get to the top of normal with no movement yet. But still you should know when things are working hard.

[time2roll]

3.5 quarts is maybe 1/3 of the fluid. Not really an effective change.
IIRC I get 11 quarts out of my 4r70w including TC.

[lawrosa]

falconbrother wrote:
I would just do a drain and fill to be safe. I do drain and fills a lot. Takes five minutes and 3.5 quarts of Dex6. If you have to pull the pan it takes considerably longer but, still not a hard job, just messy. If you have to pull the pan put out some cardboard to catch the mess.

On my 4L60e I ground the head of the drain plug off and welded an 11/16 nut in it's place. Plug comes right out. Literally takes five minutes to do the job.

Is that what yours takes? My manual states 5 quarts. But thats with filter changes. I have the 4l60e.

So if I just pull the plug and drain im looking at 3.5 qt?

[falconbrother]

I would just do a drain and fill to be safe. I do drain and fills a lot. Takes five minutes and 3.5 quarts of Dex6. If you have to pull the pan it takes considerably longer but, still not a hard job, just messy. If you have to pull the pan put out some cardboard to catch the mess.

On my 4L60e I ground the head of the drain plug off and welded an 11/16 nut in it's place. Plug comes right out. Literally takes five minutes to do the job.

[ShinerBock]

Rangerman40 wrote:
I just pulled from Ohio through the Rockies and all over Utah in 100 degree temps and my Aisin never saw above 170..... pulling a 15k lb fifth wheel.

That is mainly because the Aisin, like most modern transmissions, is coupled with a clutch locking torque converter that does not generate that much heat once it is locked. If your TC was locking and unlocking due to constant shifting, and faulty system, or it had warn clutches allowing it to slip, then I would expect that temp to rise.

[ShinerBock]

OP, if your torque converter is a clutch locking torque converter then I would say that is a high temp and you probably have some warn lock-up clutches or faulty system causing excessive slip. While I would not want it that high for long periods, it is normal for the conditions.

[crcr]

Well, I guess I'm going against the grain of responses here, but so be it -- everyone has an opinion.

250 would be uncomfortable for me. I would add a remote cooler with fan if my trans fluid were running that hot, but hey, that's just me ... I would balance the cost of adding said cooler with fan against the cost of a quality transmission rebuild -- lunch money in comparison. To me, the extra cooler would just be cheap insurance. If nothing else, the cooler would likely make the transmission last longer without a rebuild.

[Rangerman40]

I just pulled from Ohio through the Rockies and all over Utah in 100 degree temps and my Aisin never saw above 170..... pulling a 15k lb fifth wheel.

[RinconVTR]

250 is not too hot, not with modern ATF fluids anyway.

Its also critical to know where the ATF temp is being measured. Is it in the pan? Exiting the cooler? At the torque converter? Each will give different temps and its recommended to take ATF measurements exiting the cooler, I guess second best would be the pan or sump.

Note that Tundra's run 200-210 all day long (not towing) via thermostat control and their transmissions are die-hard.

[steve-n-vicki]

this is normal , after a hard pull it made it to 192

[Grit_dog]

250 isn't eggzactly conservative. But if it ain't burnt then you're fine. ATF is cheap, I'd do a fluid swap or a couple dump n fills to freshen it up.

[Frankly]

The temperatures were measured off the OBD2 with a scan gauge. Not sure how accurate these OEM sensors are, but it sure beats looking at the idiot gauges, which show very little if any change. The OEM cooler has no fan and so slowing down hurts the cooling aspect, but it does help with less heat generation. Thanks for the replies; I am glad I limited the temp to 250 F - probably too conservative, but then that's me.

Thanks for all the replies.