Will temps from 220-250 not harm most auto transmissions or just the larger the types for short distances?

 

Install a torque converter lockup switch that way you can lock the converter at low speeds so it won't produce as much heat, putting it in 4x4 low will help as well.

 

I agree the TC creates some heat when slipping, I am not a transmission engineer, so I have no qualified opinion on how much heat the TC makes slipping versus the fluid pump. My unqualified opinion is that the pump make more heat, possibly far more heat.

Anyway, lockup is something to investigate as it will reduce heat creation. From a separate issue I have been looking at, I would install an interlock from the IVS (Idle Validation Sensor(?)) on the throttle to remove lockup when the engine is at idle. Would not want to stall the engine at idle when stopped because the TC is locked. [Apologies if I goobered the sensor name, there is a sensor to detect when the throttle is not depressed, that's the one I mean]

As a possibly useful datapoint, when climbing my mountain with no payload, I'm spinning 2,200 to 2,500 RPM in 2HI at 10 to 15 MPH, transmission set to D, not sure what gear the transmission is actually in.

 

Just remember to turn the switch off before you stop, I got used to it to where I would always reach for the switch when I stopped to make sure it was off. Even when I switched to a manual transmission I would still reach for where the lockup switch used to be LOL.

 

From actual measurements, I can tell you that you are 100% wrong. When the torque converter is unlocked and the truck is working hard the torque converter creates FAR more heat than the pump does. It's not even in the same state, much less in the ballpark.

 

I will have to read up more on this TC lockup switch, however, I'd be scared I could be doing more harm than good (not knowing enough about these transmissions to know when it would be good to use the switch and when not to). Again, I'd have to educate myself more on the subject. But I guess that is the beauty of this site, to find out from others who know and have experience.

I need to learn more about the function of the Torque Converter, when the Torque Converter locks up, and what causes it to lock up on these 4R100's. Any input or reading material on this subject appreciated.......

 

Sjbj... After rereading your post and more understanding the scope of your question, it appears to me that you are at information overload.
Your original question was learning more about towing techniques. One question that was not asked ,the distance and the weight you are pulling, if it was asked I didn't see it.
I think the distance and weight is crucial to the answer to your question.

It appears your getting technical information to a problem that doesn't exist... Imo

 

I asked the distance and it was answered.

Sjbj, just put the truck into 4x4 low and D (drive) and creep up the hill at a comfortable speed. Once to the top, enjoy the spot.

 

I think he said, 10K and 2 miles. But with his four wheel drive, and dirt road, he'll have no problem in 4 low. If he was on the street and had to do this, just unplug the vacuum line to the hubs first problem solved. It would be a pain and air might go to defrost but it could be done.

 

Imho, it's not the weight or the power train, he needs to learn towing techniques and not throw a bunch of money at something that doesn't exist.. his truck is very capable as equipped.

 

Normally torque converter lockup will occur in 3rd gear around 40 mph if I remember correctly but that also depends on how much you have the accelerator pressed down. Lockup is caused when the PCM sends a signal to the transmission, and a solenoid opens to send fluid through a passage in the input shaft to the torque converter clutch making it engage so you have a solid coupling between the engine and transmission. Also if you have auto hubs and you don't want them to engage when you use 4x4 all you have to do is unplug the connector to the pvh solenoid that is under the hood on the passenger side fender, that way you won't have any vacuum leaks, like you would if you unplugged a vacuum line to the hubs.

 

I do agree to a point. I am on information overload, only because I've gotten off topic on some other details or mods with the transmission. Things I will have to read up on in my spare time.

Back to the original question at hand. I did mention somewhere in the thread that I was towing my 5th wheel toy hauler (exact weight loaded I'm not sure, but dry weight is close to 9k and trailer loaded is rated up to 14k but I don't think I'm at max at 14k). Truck has a small lift while rolling 34's. So I know that doesn't help my towing. The road I'm traveling to camp site is a steady grade up a mountain dirt road guessing 2-4 miles. It is slow going with the trailer attached. It sounds like the general consensus is to put it in 4x4 Low, leave gear selector in Drive and go. Since I really don't need the front hubs locked (unless I encounter slipping of traction), I think I'm going to try the disconnecting the ESOF connector to try the low gear but maybe save a little stress on the front hubs if not needed.

So I have received my answer from the helpful crew on this forum as to the "best" method to tow my trailer in this particular situation. This way I now know how to do my part (and not add to the problem), and hopefully my truck will do its part with no further issues. I will report back on my experience after the next trip.

 

I do have one question for you experts or more experienced out there. Hopefully to learn from my mistakes. Last year when I towed my truck twice up the same hill (once with no temperature issues to note, and the 2nd time when my transmission overheated and ultimately had to be rebuilt). If memory serves me correct, I believe I dropped the gear shifter into 2nd on that 2nd trip (left in D on 1st trip). Was that my fatal flaw? Potentially stuck in wrong gear and caused it to overheat? Too high of gear towing that heavy load up the grade? Instead of staying in Drive and letting it find where it wanted to be?

 

I keep my ESOF vacuum line loose with a .20 or .22 cal air rifle pellet stuck in the soft vac elbow. I use 2wd low moving the trailer slowly this way more often than i need to have esof 4x4 high or low and it takes only a few seconds to pop the hood pull the pellet and place the rubber elbow back onto the solenoid or just leave in this configuration and turn the hubs manually.

 

Since you are a transmission engineer, I will take your word for it. Thanks for being a member of this forum.