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.

It isn't "too" hot but it is getting up there. Also, you should have let the temp go above 225 since many cooling fans dont come on until 226~230 - which is perfectly fine.

Oh! 250! My Tahoe has never been over 205. I'd change it and check the cooling.

ScottG wrote:It isn't "too" hot but it is getting up there. Also, you should have let the temp go above 225 since many cooling fans dont come on until 226~230 - which is perfectly fine.This ^^^^^^. It's toasty but not too hot. Red line for me is 275; and it can even go above that for a short period of time. The real question is why did it get this hot?(Warning. Someone will post a 1950 chart showing how dangerous it is to have your AFT go above 15 degrees F before it is junk. :B)

I would change it and get a bigger, better transmission cooler, but that's just me. Had a transmission guy years ago tell me if people would just change transmission fluid every year he would be out of buisness. That said I change mine every two years. Good luck, John

I would go another 25 on each before I even backed off the throttle.Low gear will build some heat as the torque converter usually will not lock.It is OK to just go a bit slower too.Will not hurt to change... consider going synthetic if not already OEM fill.

Transmission Fluid Temperature | Good Sam Community

ScottG
Nomad
Jun 11, 2017
It isn't "too" hot but it is getting up there.
Also, you should have let the temp go above 225 since many cooling fans dont come on until 226~230 - which is perfectly fine.
Lwiddis
Explorer II
Jun 11, 2017
Oh! 250! My Tahoe has never been over 205. I'd change it and check the cooling.
Turtle_n_Peeps
Explorer
Jun 11, 2017
ScottG wrote:
It isn't "too" hot but it is getting up there.
Also, you should have let the temp go above 225 since many cooling fans dont come on until 226~230 - which is perfectly fine.

This ^^^^^^. It's toasty but not too hot. Red line for me is 275; and it can even go above that for a short period of time. The real question is why did it get this hot?

(Warning. Someone will post a 1950 chart showing how dangerous it is to have your AFT go above 15 degrees F before it is junk. :B)
shadows4
Explorer III
Jun 11, 2017
I would change it and get a bigger, better transmission cooler, but that's just me.

Had a transmission guy years ago tell me if people would just change transmission fluid every year he would be out of buisness. That said I change mine every two years.

Good luck, John
time2roll
Nomad
Jun 11, 2017
I would go another 25 on each before I even backed off the throttle.
Low gear will build some heat as the torque converter usually will not lock.
It is OK to just go a bit slower too.

Will not hurt to change... consider going synthetic if not already OEM fill.
ScottG
Nomad
Jun 11, 2017
Modern synthetic fluid will not be bothered by that temp. Its life is only shortened slightly and is well within normal operating expectations. The internals of a modern trans are not affected at all by that temp.
Changing it would be a waste.
lawrosa
Explorer
Jun 11, 2017
Too hot IMO. I would change it asap. Drain pan and fill.

At 250f rubber seals begin to harden and the fluid starts varnishing

I dont let mine go over 200F. It only goes that hi idleing as no air flow and the trans is matching the radiator coolent temp.

Moving and towing I stay around 150f.

With a/c on idleing the fans come on so I stay around the 150f mark also.

I put the biggest cooler I could fit inline with the factory GM cooler. I lowered the factory cooler too so it would get more air flow.
bucky
Explorer II
Jun 11, 2017
Where is the probe or are you running off of a factory gage? Also a drain and fill is not a fluid change, only a partial. That's better than nothing though. Your Ford trans probably has a drain plug in the trans pan which makes a partial change easier. If it doesn't the big box parts stores sell them but require removing the pan for proper installation. Be VERY aware of where you are drilling the hole for the install as the valve body and other components may compromise your choices due to the intrusion of the inside nut and the plug.. Try to mount it where it can't get ripped out by road debris. I partial change mine at every oil and filter service. It's cheap insurance.
jmtandem
Explorer II
Jun 11, 2017
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.

Be sure you use Tow/Haul if you have it available. It tends to keep the converter locked and the transmission from hunting and helps with temps. You should have heard the radiator cooling fan come on, hopefully, it is working. I would probably look at an aftermarket trans cooler.
lawnspecialties
Explorer
Jun 11, 2017
Turtle n Peeps wrote:

(Warning. Someone will post a 1950 chart showing how dangerous it is to have your AFT go above 15 degrees F before it is junk. :B)

:B:B:B:B