What is the upper limit of transmission fluid temperature?

Does anyone know at what temperature the transmission fluid becomes dangerously hot? How long can it remain at that temperture before damage occurs?

 

If I saw 250F I would pull over and let it cool.

 

and if your checking it and its not bright red, that could indicate that its gotten too hot, and maybe you should look into changing it.
I am not a expert with auto trans, but this is what I have always been told.
a good synthetic brand of fluid has a higher heat point but, but its best to never test any fluid on their heat range, for your trans sake.

 

actually that is the problem, when it gets too hot it looses its viscosity, and the damage can happen very fast.

 

210-220* being the maximum you should probably ever want it at. At about 260* Is when the fluid begins to break down and you should probably let it cool down as poster #2 suggested.

 

that's right, but with towing, (and the fact the op seems to have a 2012 truck) you would check the fluids before towing on a trip, and if you stop and there is now discoloring that would be a cause for alarm.

and if she does run warm, try to pull over, and let it rest, if possible let her idle, and keep the coolant flowing.

 

well that's strange. how is a owner supposed to check the fluid level?
and I am aware of that also, esp since Nissan owners are finding out the hard way that this might not be a good setup.

 

Yeah, truthfully as long as you are not overheating all should be good because the fastest way to cool down fluid is by water (hence the reason why it flows through the radiator) but also all TRD off road and sport packages come with an additional tranny cooler aside from the radiator cooler support to promote further cooling of the transmission especially during those extensive towing sessions.

In all reality I wouldn't even worry about it as long as you perform your routine maintenance and keep all items in good working order.

PS: No tranny dipstick is bullshit 'Yota.. That is all. Anytime I hear "lifetime fluid" from any manufacturer which is becoming increasingly common in some sort of attempt to make them look more impressive, I put my finger in the air and feel which way the bullshits blowing.

 

You're right, I do have a 2012, but the fact that it has a "sealed" transmission and no dipstick for it, watching fluid color is not an option. I would also be concerned that if I got the fluid so hot that it truly broke down, lost viscosity, changed colors, or whatever, it would be too late and damage to transmission will already have occurred. Thus, I have a scangauge which tells me the fluid temp, just need to know what point I need to get concerned.

I guess I will try to use the poster aboves guideline of 210-220 and ohh shit at 260, but those temps seem pretty low. I haven't towed since getting the gauge, but I got the temp up close to the 200 range going across the "mountains" in NC on I-40 with no trailer.

 

How is everyone keeping an eye on their tranny temps?

I am thinking of putting some gauges on the pillar to monitor it.

Is there an overriding assumption that the tranny temps are close to the coolant/engine temps if you have the factory tow package and supplemental tranny cooler?

 

I don't believe the manual transmissions have the sensor to monitor the temps, but the autos can use a scangauge, ultragauge, etc...

 

I thought the tow package, which is where the tranny cooler comes from, is a stand alone add not automatically included with every TRD.

 

Nope. At least not on a 2005 SR5 w/towing package.

I have an Ultraguage and tranny temp is not an option on my truck. So I was looking at some aftermarket gauges that folks are mounting on pillars and I was wondering where they are getting the temp feed from.

 

This is the write-up I followed: works very well. I have an auto meter sport comp 3357 gauge. I just put in a piller pod by Lotek.

 

Typical ATF has a flash point of 315-325 Degrees.

 

How much time and money invested in that setup?

Nicely done I think. Could be a good project before the temps get up here.

I guess I just wonder why Toyota doesn't have stock sensors. Or I guess I wonder what would trip the tranny temp dummy light....why not send that to an SG or Ultragauge?