Transmission Temp Operating Range? (A340F)

[BamaDrewski]

As you guys may have seen, I bought one of those OBDII Bluetooth gizmos. I have been watching my transmission temperatures. I put a large transmission cooler on my rig years ago and bypassed the radiator to avoid the “pink milkshake” disaster. My transmission is running between 160-191 degrees according to the OBDII Bluetooth sensor. I would rather have a cooler running transmission than a hotter one and I am happy with these temps. (On another note, the engine coolant runs consistently at 194-196 degrees)

QUESTION: Does anyone know the normal operating range of temperature for the A340F transmission?

I have ZERO issues with my original transmission and it now has 250K miles and counting. It shifts like new and the auxiliary cooler has been on FOR YEARS.

Any comment/help/input would be appreciated!

 

[Qyota]

From my experience (ScanGauge II), it depends a lot on the air temp. In winter, I might not see ATF temps over 100F in my 8-mile commute to work. Now, when the air is in the 40-60 range, ATF doesn't seem to go over 150-160. In the hottest months, it'll creep to 190 or so in stop and go traffic. While in over drive, it will come back down to 160-ish, even in the hot months.

I have a smallish B&M cooler, fully bypassed. Does the trick!

 

[LittleCaesar]

You know I could not resist:
Amazon.com: Liqui Moly 5135 ATF Additive: Automotive

As long as the temp stay below 200F 95% of the time and old ATF is drained and new ATF is added every 50,000 miles or so you should be good to go.

 

[jeremyc74]

The range yours is running at is the normal operating range. Seeing 200F on a regular basis will require more frequent fluid changes, but it's not uncommon for someone who's towing. I have a standalone temp gauge on my RV (transmission overheating is a big deal on those) and that's exactly where it runs until you get into extremely high ambient temperatures at altitude. I've only seen it cross the 200 degree mark in 105 degree heat in the high deserts, and at that point I start to slow down.

 

[kball]

I don't think I've ever seen a normal operating temp range in the FSM for the trans. From what I've read online the trans temp light doesn't come on until 250-275 or higher so that should give you an idea of what Toyota considers "normal".

 

[jeremyc74]

I don't think I've ever seen a normal operating temp range in the FSM for the trans. From what I've read online the trans temp light doesn't come on until 250-275 or higher so that should give you an idea of what Toyota considers "normal".

It's my understanding that the fluid degrades faster with higher operating temperatures, and operating temps above 175 degrees reduce it's life substantially.

There are a lot of charts out there that show this, but most of them are provided by companies selling transmission coolers, so they have to be taken with a grain of salt.

Here's an example:
Transmission Oil

 

[kball]

It's my understanding that the fluid degrades faster with higher operating temperatures, and operating temps above 175 degrees reduce it's life substantially.

There are a lot of charts out there that show this, but most of them are provided by companies selling transmission coolers, so they have to be taken with a grain of salt.

Here's an example:
Transmission Oil

Yep, I agree. Higher temps mean fluid needs to be changed more often. I just think people freak out too much about temps in the 200+ range. As long as it's not there continuously I don't see an issue. Mine gets that hot often depending on the situation(not normal stop and go city driving) and to me it's totally normal. It never stays there for long.

 

[NOT ME OR SOMEBODY]

seems to be normal temperatures

Your temperatures seem to be normal.

I agree cooler the trans. temp. better as long as it get hot enough to drive the moisture out.

One other thing to add:

My engine temp was 190* and would go higher if I got in traffic. 200*+

I thought it should be cooler so I changed the newer Toyota thermostat to a 170 or 180* from NAPA. The NAPA looked cheaper that the Toyota in size, but it's been in there for over a year and the Scangauge shows it holding at 180* on Xway and then 190 or so if traffic.

 

[BamaDrewski]

You know I could not resist:
Amazon.com: Liqui Moly 5135 ATF Additive: Automotive

As long as the temp stay below 200F 95% of the time and old ATF is drained and new ATF is added every 50,000 miles or so you should be good to go.

Funny man....funny! I know uou LittleCaeser are secretly buying up all the Liquid Moly products he can get so he can stockpile and corner the market (LOL!) Rumor has it you are using it on everything from lawnmowers to dishwashers.....

Seriously, I did a swap over to Mobil1 Full Synthetic transmission fluid a few years ago and do a regular drain and fill. (Comes to about 4 quarts everytime). Mobil1 transmission fluid is not inexpensive but so far, my transmission is doing great at 250K miles plus.

 

[Drcoffee]

 

[LittleCaesar]

Funny man....funny! I know uou LittleCaeser are secretly buying up all the Liquid Moly products he can get so he can stockpile and corner the market (LOL!) Rumor has it you are using it on everything from lawnmowers to dishwashers.....

Seriously, I did a swap over to Mobil1 Full Synthetic transmission fluid a few years ago and do a regular drain and fill. (Comes to about 4 quarts everytime). Mobil1 transmission fluid is not inexpensive but so far, my transmission is doing great at 250K miles plus.

Then you should be fine. Mobil 1 ATF is good stuff, though I have never used it in the 4runner but in plenty of American autos. Fluids, other than oil, have always been changed out by me at 50,000 miles with never a problem in 20 years of car/truck ownership.

I do use the Liquid Moly MOS2 in a 17 year old lawnmower and it has cut down oil consumption (bad rings in it) by at least 50%. Nothing wrong with the LM line. Do get the Blackstone report when you drain it.

 

[jgue467]

...
QUESTION: Does anyone know the normal operating range of temperature for the A340F transmission?
...

I would say as designed by the great toyo, the Normal temp would be very much the same as the engine coolant since that is how it is supposed to be cooled. Mine was that way (192-199) just like engine temp Until I bypassed it 4 yrs ago. Now it will Eventually heat up to 195 give or take yet takes 45 mins to do that as opposed to 10 mins before. It also varies quite a bit, yesterday I hauled 1000lbs of river rock in truck and it varied on hilly terrain anywhere from 165-195. I would think a steady temp would be better yet like yours it doesn't seem to mind. I also run a magnefine filter + drain/fill the trans at least annually, comes out Pink.

 

[SpidermanGeek]

From my experience (ScanGauge II), it depends a lot on the air temp. In winter, I might not see ATF temps over 100F in my 8-mile commute to work. Now, when the air is in the 40-60 range, ATF doesn't seem to go over 150-160. In the hottest months, it'll creep to 190 or so in stop and go traffic. While in over drive, it will come back down to 160-ish, even in the hot months.

I have a smallish B&M cooler, fully bypassed. Does the trick!

I haven't had my B&M 70268 cooler bypassed and temp gauge all that long, but so far I am getting the exact same readings/results as described above.

 

[turbodudey2]

I have a larger cooler, about twice the size of the popular B&M 70268. Normal operating temp for me is 145° (even in the summer when it's 110° outside). Stop and go traffic will make it creep up to about 160°, and wheeling in 4HI will go up to 180°. Anytime the TC is locked up it runs at 145°, and the max I've seen while driving in 4LO is again... 145°.

 

[Kotrin]

Temp check-in (after 13/14 Months)

Reviving an old thread after reading lots of pages (and searches) about ATF Temp. This last weekend My transmission was higher than comfortable, but did lots of elevation changes. I'm getting ready to do my overlanding trip and I know its TON of 10-20 mph and hills/curves. I am going to TRY to change my ATF prior to going and will change it afterwards but I expect it will run at 200 +/- 25 easily for the entire 7 days. Even though I have the bypass cooler, I feel that it should be fine.

My question is that I am so swamped prior to my trip in 2 weeks that I don't know if I can get my tranmission fluid changed with-out going to a Jiffy lube type thing. I would like to wait till after the trip and change it then. How does everyone feel about their temps since the post over a year ago?? I'm hoping you guys will have seen 200's often during hills/trailers and off-road trails.

My solution is to run with O/D off and ECT on during my trip. My father believes the cooling is directly related to my engine RPM's. The faster the engine turns, the faster the transmission fluid goes due to pump inside with coorelation to the RPM's(Hopefully that isn't to much of a ...weird sentce; damn medicine).

Let me know! Thx

 

[St Runner]

Biggest factors for temperature are the TC being locked, engine load, airspeed and ambient temperature. So if you are running hard at low speeds on a hot day it is going to put out a lot of heat that the cooling system cannot keep up with. Take the time to do a simple drain and fill, it takes a 1/2 hour and you will worry less about it.( And if you cannot find a 1/2 hour in your life you have bigger issues than your transmission heat). The most important factor is knowledge. Pick a temperature you draw the line at like 230 and stop and let it cool down if you reach it. Most things in life break because they are pushed past what they can tolerate

 

[Kotrin]

Biggest factors for temperature are the TC being locked, engine load, airspeed and ambient temperature. So if you are running hard at low speeds on a hot day it is going to put out a lot of heat that the cooling system cannot keep up with. Take the time to do a simple drain and fill, it takes a 1/2 hour and you will worry less about it.( And if you cannot find a 1/2 hour in your life you have bigger issues than your transmission heat). The most important factor is knowledge. Pick a temperature you draw the line at like 230 and stop and let it cool down if you reach it. Most things in life break because they are pushed past what they can tolerate

Understand and thank you. I was looking for information as I originally asked and it coorelates with your "The most important factor is knowledge." I was looking for someone who have had the setup for a year to provide data.

Thank you again for providing this information.

 

[mtbtim]

Understand and thank you. I was looking for information as I originally asked and it coorelates with your "The most important factor is knowledge." I was looking for someone who have had the setup for a year to provide data.

Thank you again for providing this information.

You might find these two threads I started helpful:

http://www.toyota-4runner.org/3rd-g...sion-temperatures-how-relates-life-fluid.html

http://www.toyota-4runner.org/3rd-gen-t4rs/217667-trans-temps-bypassing-using-external-cooler.html

I agree what somebody already told you. A drain and refill of the transmission pan takes no time at all to do. You'll be renewing around 5 of the 12 quart capacity of transmission. Just remember to get yourself a new crush washer for the drain plug.

 

[Kotrin]

You might find these two threads I started helpful:

http://www.toyota-4runner.org/3rd-g...sion-temperatures-how-relates-life-fluid.html

http://www.toyota-4runner.org/3rd-gen-t4rs/217667-trans-temps-bypassing-using-external-cooler.html

I agree what somebody already told you. A drain and refill of the transmission pan takes no time at all to do. You'll be renewing around 5 of the 12 quart capacity of transmission. Just remember to get yourself a new crush washer for the drain plug.

Thanks!!

I read through the FSM some more over the weekend while my son was here. It's interesting to read about the temperatures they say is okay and the 'bad point'. I'm getting it changed by Jiffy Lube since I can't crawl around under my vehicle and I don't have people to do it for me =\

But Thank you VERY much i'll read through those.