Real world towing experience

You are welcome to go find one. Scholar.google.com is an excellent place to start. So are the citations on wikipedia

 

What? Of transmission fluid? That's not what happens, manufactures write specs based on material science and there own internal testing. They don't make that stuff available to competitors for "peer review". The evidence of the testing is that the thermostat regulates the temperature at 180 degrees, from this we can deduce that Toyotas testing says that 180 degrees is the right temp and more is bad. Also you could send a sample of trans fluid to blackstone labs and ask them at what temp the fluid degrades at. They would also have a lot of practical data on when fluids break down from the testing they do for there costumers.

 

Why are we suddenly acting like we can't understand excess heat = bad for auto trans?!

 

Maybe I can help....a little. I towed this for about 10 years. Many weekends. Through East coast hills and mountains a the flat areas of Ohio, Michigan, Illinois, etc. I never towed in anything but 4. Revs stayed higher than normal but the truck acted like it was made for it. Never had any issues with overheating. I had my first transmission flush at 60,000 and had my 2nd flush at 93,000 after I sold the camper. My trans, to this day, shifts smoothly and flawlessly.

 

How much did "this" weigh?

 

I’m not sure the hunting is actually this issue with trans temps. On my second gen, the torque converter is locked in fifth, and if it downshifts to fourth it is unlocked and it is the unlocked status that generates excessive temps. On the other hand, if I shifted to fourth, the torque converter will remain locked, and not generating much heat, until it downshifts to third. I monitor temps at the pan and the torque converter, while towing with an ultraguage. I also have installed a auxiliary Trucool transmission cooler. Trans temps are important imho. I love my truck too much to shorten it’s life with an easily controllable issue.

 

I've pulled a utility trailer loaded with 3000ish lbs several thousand miles all over the east. I pulled a 3000-3500 lb pop-up camper for 13 years with my Tacoma, but mostly on shorter trips. I've pulled a 4000-4500 lb travel trailer maybe 100-150 miles total. Enough to know that is as much as I want behind the Tacoma. It pulls it, but a bigger truck pulls it a LOT better.

As a default DO NOT operate it in OD when towing. You'll run cooler and your engine and transmission will last longer. If you're pulling a light load on level ground and want to shift into OD then give it a try. But if you sense the engine starting to lug down get out of OD. Use common sense. Your engine is working harder, and hotter, at 2500 rpm pulling a trailer than at 3500 rpm.

Just because it is an automatic transmission doesn't mean you can't control what gear is best. The transmission will downshift, but only AFTER your engine starts working hard. It can't see the road ahead and anticipate the need to downshift early. If you see an incline and know the truck needs to be in a lower gear it is easier on everything to downshift BEFORE your engine starts to work hard and before you lose momentum. And don't be afraid to downshift going downhill. When in mountains I drive my automatic like a manual without a clutch and am constantly choosing the best gears. Even when not towing.

 

When an auto is "hunting" the TC is constantly locking and unlocking as it shifts, this is what causes the heat buildup, same as towing in an unlocked gear. FYI on a 3rd gen gears 4,5,6 are locked.

 

Happy towing to all. This thread is too salty for my tastes. May your tranny live long and proper. I’m tapping out!

 

Between 4 and 5,000 depending on what I had to load due to camping area and how long I was staying there. Mostly fields and remote lots. always had the truck loaded too. 3-4 dogs in the back in RuffTuff kennels which were anchored. I was a field trialer. Bird dogs are a blast!

 

nice

 

I don't have a problem letting my transmission shift for me under normal conditions. I do have a problem abusing the transmission and prematurely wearing it out/overheating it from excessive shifting. The transmission manufacturers say to downshift if there is excessive hunting to prevent excessive wear and damage. I'm not going to question the people who designed these transmissions. They know much more than I do about them.

 

There hasn't been a peer reviewed study to actually prove that, so its totally impossible for that the be true.

 

Lol. I read that after I responded... I don't even know what to do with that statement...

That's now how this works... That's not how it works at all.

 

Toyota has not said that in the manual. It’s a common misconception; possibly an anachronism. If it were a true issue, Toyota would design the transmission to downshift for you.

 

You'll be fine. Just stay within your limits and take it easy.

I towed 5000 lbs (track car on a U-Haul trailer), with a bone stock truck for about 500 miles over the weekend. 15 mpg on 5th gear (manual). Went over some hills too with some wind I felt. I did have to use 3rd gear for some steeper inclines (usually used 4th gear). For declines I just used 4th and it's fine.

My truck: '22 V6 4x4 TRDOR DCSB 6MT. Bone stock. No WDH, no rear airbags. It comes with the tow package, which is standard for 4x4 V6 Tacomas after a certain year I believe.

Here's a thread that gave me confidence:

https://www.tacomaworld.com/threads...ays-of-towing-5-600-lbs.774588/#post-27682402

Edit: I realized you have a '07 Tacoma. Is that the truck you are using to tow instead of a 3rd gen? Because you posted on the 3rd gen section just FYI

 

Toyota says to tow in s5 or lower... Toyota also has programmed the transmission to lock gears if the transmission overheats. Sure you could let it overheat, but I like my things lasting so I would rather prevent it from overheating.

Regarding the transmission "downshifting for you" the manufacturers try really hard to do this. Of course it's a wicker hard problem to solve since it would require knowing what's about to happen. This means that there are still conditions where the transmissions can still hunt. My point was IF the transmission starts to hunt downshift to prevent excessive shifting.

If hunting isn't a problem why do the manufacturers have patents out on how to prevent hunting?

Here is a Chrysler patent.
https://www.google.com/url?sa=t&source=web&cd=&ved=2ahUKEwiH-pWJ8oj6AhW7kokEHeG2A904ChAWegQIEBAB&url=https://www.freepatentsonline.com/5669850.html&usg=AOvVaw1oCdfPBVCsHNXC887oMWfR

And a Ford patent.
https://www.google.com/url?sa=t&source=web&cd=&ved=2ahUKEwiHwp_a8Yj6AhW-kIkEHTxUCE8QFnoECAoQBQ&url=https://patents.google.com/patent/US6098004A/en#:~:text=Operation%20of%20the%20transmission%20in,corresponding%20changes%20in%20vehicle%20speed.&usg=AOvVaw2Z24opsvLJddRDxMGhIMmm

And a patent from caterpillar that specifically states that hunting can cause wear or damage.
https://patents.google.com/patent/US8568271

 

I think an agreed on definition of “gear hunting” would help this discussion, but anyway…

Read the manual carefully. It says to use S5 or lower when engine braking and towing.

I interpret the patents as evidence that the automobile manufacturers have solved this problem for the owners and they can stop worrying about it. It may have been an issue in the past when automatic transmissions were not electronically controlled.

 

Correction it says "To maintain engine braking efficiency and charging system performance , do not use the transmission in D. If in the S mode, the transmission shift range position must be in 5 or lower."
Note the comma location. Its lists engine braking and electrical performance as benefits of not using drive, but it specifically states not to tow in drive, and in s5 or lower, not to only use s mode when engine braking.