Transmission Temp

[volpe30]

BTW, very nice set up you have there!

Thanks, I really like the Xventure. Lots of adventure/off road trailer options these days, all have pros and cons, but for me and my family it’s been great.

I think the problem is there is no clear answer. I would love if a mechanical engineer who designs and builds transmissions, especially Toyota transmissions, would jump in and give some hard facts based on design and materials. Or a chemical engineer who truly understands the chemical makeup/properties of the ATF in our vehicles and what it can handle, again based on facts that trace back to their chemical design/makeup, would comment as well. The closest I’ve gotten is the video I posted by the guy who builds transmissions and said normal operating temp is 10-20 degrees above engine temp, which for me would be 195-205 or so, and to be concerned when temps get above 250 up to 300.

I definitely don’t think the transmission fluid is lifetime given as much towing as I have and will be doing. Throw into that the trails in Idaho, Utah, and Eastern Oregon are dust bombs I will certainly switch it out at some point. Right now I’m thinking 60,000 miles will be that point.



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[wfo9]

i bet you also believe that lifetime fluids never need to be changed

Not sure if you are talking to me or not.. But no. never implied that.

Changing the trans fluid at 20k just makes 0 sense. Even 60k makes no sense to me unless there had been extreme abuse.

 

[volpe30]

Even 60k makes no sense to me unless there had been extreme abuse.

You’re probably right. If I did it then it would be out of an abundance of caution. I plan on driving my truck until it disintegrates underneath me, so I probably lean a bit towards the over maintain side of things. At the same time I don’t want to just do useless maintenance and, more importantly, unnecessary spend money. That’s why I’m trying to educate myself best I can so I can find a happy medium.



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[e60ral]

Not sure if you are talking to me or not.. But no. never implied that.

Changing the trans fluid at 20k just makes 0 sense. Even 60k makes no sense to me unless there had been extreme abuse.

why are you using an old school mindset to maintain a modern vehicle if it says lifetime fluid?

 

[nglayton]

with documented or first hand knowledge and facts.

rofl :rofl:

 

[volpe30]

rofl :rofl:

Not sure I understand, but okay.


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[Rmack]

You should not use an old school mindset to maintain a modern vehicle. What's next.. change your plugs and points every 20k?

Plug technology and fluids are apples to oranges. I explained in my post why I changed my fluids early.

I understand you have your opinion and that is great. I was just giving mine. I have rebuilt many motors and transmissions in my lifetime. I also used to do fluid analysis for a living.

Being a modern vehicle does not do away with friction and heat build up. Yes the fluids today are awesome, but they still degrade. Lifetime fluid is on the shelf right next to unicorn food.

To each their own. Put 5k worth of mod's on a vehicle but scrimp on the fluids that keep it in top shape.

BTW, the fluid that came out at 20k definitely looked a lot darker than the new that went in. Plus, I am now positive that the fluid is exactly at the correct level.
I also changed my rear diff at 10k and my 1st oil change was at 2k. I must be crazy.

 

[nglayton]

Not sure I understand, but okay.

No worries, I was just trying to be funny.

In my experience I have found public internet forums to be about 10% of which you seek and 90% total BS.

Now while this T4R board is 1000% better than most, and no offense to anyone is intended. I have personally gotten a ton of great stuff from everyone here.

I feel that the odds of finding documentation to be almost never, odds of finding first hand knowledge is always, but the odds on wether or not it is fact, is really in the eye of the beholder.

 

[wfo9]

You won't get facts here. Even if they are facts coming from a contributor they have to be considered opinion and/or one off first hand experience. That is just what this place is.

So, go with what the mfg recommends as fact when in doubt. The design is very specific. There are reason for the interval. Messing with the interval can do more damage than good. I could go into the reason why, but it would just create a bunch of unnecessary discussion and arguments. So, don't listen to me... listen to the MFG of said product on recommended maintenance or do whatever you want if it makes you feel warm and fuzzy inside.

I sure hope those filling up the trans thinking the mfg put the wrong amount in understand the refill procedure. It is very specific to temp.. You will definitely cause damage filling to the top blindly. I'm sure you know this, but thought I would mention it. Never heard of Toyota not putting in the correct amount from the factory. Dealers, sure... they could mess up just about anything.

 

[MossJenks]

I would love if a mechanical engineer who designs and builds transmissions, especially Toyota transmissions, would jump in and give some hard facts based on design and materials.

Well, those guys aren't lurking around a discussion forum looking to jump in when a bunch of nervous nellies get their panties bunched up and why would they? They'd say "follow the manufacturer's recommendations" and somebody else would say "you're stupid".

It just so happens that a whole team of Toyota engineers got together and wrote a book on the subject. It's called the "Warranty and Maintenance Guide". If you bought your vehicle new you should have been provided with a copy. I'd link you to a new copy online but Toyota USA's system seems to be down at the moment.

Good lord guys, you're driving the most durable product in the automotive industry. Catastrophic failures with any of the major components are extremely rare. You really hope to better the Toyota engineers with a bunch of gum-flapping on a general-interest discussion forum? Please. :rtfm:

 

[volpe30]

I appreciate everyone’s feedback and opinions. I know it’s just a forum, but figured it couldn’t hurt to try and see what information was out there.


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[honda99ex]

This. Sounds like you're towing with the transmission in D. When I tow, I use 4S and my temps stay easily below 200. Generally, in the 170-180 range. If I switch to 5S or D, the temps will climb to 200 and above very quickly, especially on hills. You'll lose a little more MPG but, it's not a huge difference.

You could probably use D on flat ground if your speeds are reasonable. My typical load catches a lot of wind and when I get to 65mph or above, the transmission struggles to stay locked up.

I always have it in 4S when I tow on the road. On dirt, on more technical terrain and when going up steep grades, I’ll downshift manually and switch to 4 low as needed. So I’m hitting those temps under those circumstances.

One thing I realized today in researching scan gauge x codes is I’m pretty certain the reading I’ve been getting is at the torque converter. I put in a different code that is supposed to be the pan, or somewhere else in the system. I’m interested to see if that makes a difference on my readings. But either way, the trans oil is still hitting those numbers.


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Just so I have this correct.... When I tow I usually keep it in s4 around town and almost up to highway speeds (up to 55mph) but when I'm on the highway going 72-75mph i swap it back into D. Is that wrong? Should I be swapping to s5 or just keep it in s4 though it revs super high? This is for 180 miles with up and down terrain but not little steep hills. Long gradual uphills and down hills. I can maintain the speed no problem in D but I have to keep my foot on it.

 

[catrains]

the fluids are to be replaced when the condition of them is bad. smells bad / off color /particles and components not working properly.

with a transmission on fluid changing pan drop and cleaning this is all about checking the fluid condition , and this should be done at every oil change .. all of the vehicle fluids should be checked and if its looking bad/wrong/smell etc then it should be replaced. BOOK IS ONLY A GUIDE !!!

NOT many check the tranny fluid because its a PITA !

so most owners will wait until it starts shifting erratically , then check the tranny fluid LOL.....

TOYOTA book says CHECK ALL FLUIDS @OIL CHANGE INTERVALS ..

 

[(none)]

Just so I have this correct.... When I tow I usually keep it in s4 around town and almost up to highway speeds (up to 55mph) but when I'm on the highway going 72-75mph i swap it back into D. Is that wrong? Should I be swapping to s5 or just keep it in s4 though it revs super high? This is for 180 miles with up and down terrain but not little steep hills. Long gradual uphills and down hills. I can maintain the speed no problem in D but I have to keep my foot on it.

All depends on how much you want to pay attention to your driving. Use D instead of S5. That way the torque converter locks in 4th and 5th. in S5, it only locks in 5th.
You will have to pay close attention if you do tow in D, are you monitoring your trans temps? The torque converter will unlock in 5th and just stay unlocked for long periods of time if you aren't paying attention, which will heat the trans up very quickly.
Also, 3k rpms in 4th gear is by no means super high. These things will sit at the red line all day if they need to, they have the cooling capability. Let it breathe, you aren't going to hurt anything.

 

[honda99ex]

All depends on how much you want to pay attention to your driving. Use D instead of S5. That way the torque converter locks in 4th and 5th. in S5, it only locks in 5th.
You will have to pay close attention if you do tow in D, are you monitoring your trans temps? The torque converter will unlock in 5th and just stay unlocked for long periods of time if you aren't paying attention, which will heat the trans up very quickly.
Also, 3k rpms in 4th gear is by no means super high. These things will sit at the red line all day if they need to, they have the cooling capability. Let it breathe, you aren't going to hurt anything.

I'm kind of set it and forget it kind of guy.... So basically I only use s4 and D. I tried 'shifting' on my own up and down the S mode and it was great until I drop it too low every like 15th time and it would jerk... Thereby nullifying any effort I felt I was doing to preserve the tranny. lol

I haven't monitored the temps. I have one of those OBD dongles I wonder if I can read it off that? I can play around with that.

As for being in D, in theory it shouldn't drop any more below 4th than being in s4 should it if I'm maintaining 75mph?? I mean in D I'll have 2 shots of the torque converter being locked 4th and 5th so the engine can rev lower? Boils down to: is s4 keeping the torque converter locked up more often than D going 65-75mph??? Is there a way to see tell if the torque converter is locked? Is it generally accepted that it can rev at 3500rpms 3 hours straight no issues?

Asking because I take a particular trip where if I fuel up ethanol free I don't have to re-fuel/stop but I'll barely make it. So anywhere I can save fuel aka not rev so high it would help. I could also drive slow as all hell at 55 mph and save a lot of fuel but Second part of the equation is I haul horses and literally I am preoccupied with them not killing themselves back there/flipping the trailer/ killing me and destroying the 4Runner, etc so my mind is on the cargo not the Toyota.

Thanks

 

[wfo9]

Boils down to: is s4 keeping the torque converter locked up more often than D going 65-75mph??? Is there a way to see tell if the torque converter is locked? Is it generally accepted that it can rev at 3500rpms 3 hours straight no issues?

Yes it locks up in s4 easier than D.

You can tell if it locks in D by feel. In other gears it is hard to tell so you need to scan... there is a mfg specific pid that reports the converter status, but I don't know of a generic scan tool that will display it. Toyota TIS will display it but for whatever reason.. Toyota and other MFGs don't document the mfg specific PIDs. There is a pay to join ODB group that shares this information that some of the scan tool mfgs are a member of. Otherwise, you have to log the CAN bus network traffic to figure it out...So, someone like ScanGauge could possibly add it or could give you the specs to add it as a custom PID yourself.

3500 for 3hrs should be no problem at all.

 

[honda99ex]

Yes it locks up in s4 easier than D.

You can tell if it locks in D by feel. In other gears it is hard to tell so you need to scan... there is a mfg specific pid that reports the converter status, but I don't know of a generic scan tool that will display it. Toyota TIS will display it but for whatever reason.. Toyota and other MFGs don't document the mfg specific PIDs. There is a pay to join ODB group that shares this information that some of the scan tool mfgs are a member of. Otherwise, you have to log the CAN bus network traffic to figure it out...So, someone like ScanGauge could possibly add it or could give you the specs to add it as a custom PID yourself.

3500 for 3hrs should be no problem at all.

So basically slap it in s4 and let the truck be.... And worry about my cargo not trying to kick out the side of the trailer...

Also sorry to thread jack but thoughts on supplemental tranny coolers? Only because I probably tow like 1% of my total miles. Some on the net say no such thing as running a tranny too cool but others say the opposite. I live in the NE and it does get cold, also multiple cold starts in day. Like I'll drive sit for like 2 hours, drive, repeat....

 

[SirWilliamGoes]

Figured Id hop on here and revive this thread a little

I had my second transmission service at 200k this time done by someone other than the dealer.

At 215k while in 4Hi in deep beach sand in Baja I got a warning light saying the transmission temperature was too high to put in park and let cool. I did that then when it was cool I switched to 4Lo and continued on. I should have been in 4Lo to begin with but wasn’t.

A few months later climbing up a steep grade on the Idaho BDR went into 4Hi when it started to get a bit rough and shortly thereafter I got the transmission temp too high warning again.

I’ve owned the truck since new, and driving in extreme conditions since new and this is the first time Ive ever had these warnings. So I decided to purchase an OBD reader and an app that will allow me to track the temps. While in the San Juan’s on steep climbs Ive been seeing temps between 210-240. Reading online this is bad I decided to start by doing a drain and fill of the fluid. The fluid definitely looked and smelled bad. I will have to do this multiple times to get all fluid changed which I will do over the next couple thousand miles.

This is my thought process here.
First and foremost, I never monitored temps b4 so Im not real sure what “normal “ for my setup is
My understanding is the warning light does not come on until 300 degrees so the thought of 250-300 being high seems understandable. And 200-240 may actually be normal. The folks over at Toyota are pretty sharp, if 250 did damage, I bet they would make the light come on at 240
I would like to see a newer stock 4R with the same app and reader do these similar grades to see what temps they run.
In all this I also found my radiator was pretty caked up with mud dirt and debris which can affect these temps as I understand they run through for cooling.

My next steps
I think the last shop did not use Toyota WS fluid therefore it was not as strong and I indeed overheated it in Baja making it even weaker. To fix this I will cycle through new Toyota Fluid over next few thousand miles
My radiator bracket is also cracked so I will get a new radiator from Toyota and throw that in which will likely cool the temps down further
After doing all that I will consider a trans cooler, since I dont tow and Toyota didnt seem to think there should be a cooler I doubt I will install one.

Ill report back as I go through this process
Thanks for coming to my TED talk.

 

[1000MPH]

Are you using lower gears or just keeping it in D? I’ve never seen high temps like that off road but they definitely spike on steep mountain highways if I don’t downshift. Highest temp I’ve seen is 221° at the torque converter and 201° in the pan with a 106° ambient temp. 213° at the TC is quite common for me on trips over the Sierras.

 

[SirWilliamGoes]

Using lower gears when on steep grades