High Transmission Temp Warning - Stalling in 4lo

I had heard of it happening before it happened to me but it was still alarming. Then it happened again on same trail and second time it didn't bother me as much. Now its like part of it and i carry on lol

 

I agree. Exactly why I'm asking questions beyond someone assuming what they think it is.

Exactly why I'm asking questions; I'd love to know why it does it, so I can set myself and my family up to avoid it. Thanks for your input and experience. I think its helped narrow alot of things down to what it "probably" is that's occurring.

 

I think two footing is still the root of the issue. I just don't know the measurable amount of both pedals depressed that causes it. Thinking back to the accelerator pedals stuck in the early 2nd gens because of floor mats, and trucks getting the "shut truck off" safety feature when both pedals are depressed simultaneously, this makes the biggest case for me. Maybe trans load has some sort of influence on it, maybe not. Looking forward to hearing some more testimonies of it occurring to hopefully rule some things out.

 

I dont two foot. Well I do sometimes but it happens when I'm not two footing.

 

But is it happening when you are depressing both pedals (even with one foot lol)? I'm more than happy to be wrong in my theories. I just want the answer at the end of the day.

 

Its normal like said above, happens twice as fast/twice as sensitive in double low.

 

Lets look at whats happening inside the transmission .

Torque converter
As far as protecting the automatic transmission from rolling back , I beleive you can drop that out of the diagnosis for a stall .
The torque converter is designed to slip . Its a fluid clutch . If your foot is lightly on the gas moving forward and suddenly the incline changes and you begin moving backwards , no damage is being created from this inside the transmission or the torque converter .
You can roll the truck back while in a forward gear all day as long as the engine is running

Transmission fluid / filter and transmission pump
When you are on a steep incline , transmission fluid is sucked up from the transmission pan through the " front " of the transmission filter to supply oil to the transmission pump . If for some reason the transmission was a bit low on fluid ( very common ) , there is a possibility of pump starvation . This would cause a pressure drop inside the transmission causing the truck to roll backwards due to a loss of fluid to your forward clutch .
I beleive the stalling issue occurs because of a pressure drop inside the transmission . Like a fail safe to prevent accidents .
The engineering team who designed these trucks still beleive the world is flat

 

I have had this happen to while rolling backward in D

 

What about the transmission's input speed sensor vs output speed sensor causing it to go to fail-safe?

 

That could be the case but the situations in which this occurs, the truck isn’t rolling back because of the transmission clutch, it’s rolling back because you lift your foot off the gas and gravity pulls you down and you press the gas again to try to maintain the climb.

This also happens on flat tracks climbing steps.

If it was a starvation issue then it seems it would occur every time you are in those situations. I can stall my truck on whale tale and take the same line again and not stall, or choose to deliberately stall.

 

Yup I thought about those sensors before posting .
Nothing out of the ordinary came to mind .
When either input or output speed sensors have a brain fart , it trips a hard fault .
Guys would also be reporting hard codes in computer memory

 

You sure it would generate a DTC?
As I understand it, to generate a transmission DTC, normal mode(regular vehicle operation) detection uses a 2-trip logic; check mode(requiring Techstream) uses a 1-trip detection logic.

 

Did anyone actually find a solution to this problem? My truck would usually do it like twice a year. Recently I installed a pcv relocate kit and it’s been doing it twice a trip now. Same wheeling, really strange and mine never does it in double low. I put my catch can back on and I’m going wheeling this week to see if it’s related. I know it shouldn’t be but it’s the only change that was made. It’s not a big deal but more of an annoyance, people assume it’s a manual lol. I may go down the rabbit hole on this one we’ll see what happens.

 

As far as I know, just lots of theories and no real answers. I've personally gone completely away from 2-footing and utilizing e-brake more since I felt that was a reasonable theory, but not many others seem to agree, so honestly, I have no idea.

 

My experiences with this. No stalling, but the only time my transmission fluid temp ever goes high is in 4wd, going slow up long inclines off road. No faster than 15mph. Does not matter if I leave it in D, or use it in manual mode in first to third gear. It can go over 230 degrees in these cases, but drops back below 210 as soon as the trail levels out.

That happens even if the outside temp is less than 60F.

The outside can be 100F driving around town or on highways, and the tranny temp seldom goes over 205 even pushing high rpms.

In the case of my 2016 TRD OR, it is always like this.

Even a slow crawl up a long incline (not that steep either) in 4wd in cool weather appears harder on the tranny than gunning around town on super hot days.

So I imagine a steeper hill and a longer run in 4wd might present an issue like some have described.