Trans overheated!

The radiator(185) adds heat to the trans fluid to heat it up faster for better MPG so I by passed it.

I have the obdlink lx and dash command app.
I may need to add another app with trans temps.
But I know it runs way cooler than stock and my fluid looks like new after a few years but it would be nice to monitor the temps.

Do you know an app that has trans temps? It would help checking fluid levels also.

 

I haven't used it, but other people are using the torque app I think. The trans cooler is in the bottom of the radiator, remember heat rises, the bottom of the radiator isn't 185°, I actually think my tranny would warm up faster without the radiator in the loop. Do me a favor and IR the lower radiator hose sometime and tell me what the temp is. My transmission runs too cool most of the time, I have a short drive to work and most of the time I can't get the transmission over 100°. On the highway in the summer I see between 130° and 150° Toyota says normal operating temp for the a750 is 122°-175°.

 

Could be, I'll check it out. Both lines on mine are on the side of the radiator.
I know my FRS has a heat exchanger That heats and cools the fluid. I plan on disconnecting the coolant lines and adding a bigger cooler.

 

The tundra and third gen tacos have a heat exchanger and thermostat that heats the tranny fluid to the same temp as the engine coolant, 185-190°. Some people are reporting seeing temps around 220° towing. The radiator doesn't add any heat to the transmission unless you are moving too slow to cool the antifreeze before it reaches the bottom/ cold side of the radiator.

Its on the cold side of the radiator though. I actually thought about adding a thermostat to my truck to warm the fluid up and keep from over cooling the fluid in the winter, then I might add a bigger cooler and delete the radiator cooler to avoid the pink milkshake possibility. I emailed Valvoline and asked them what they thought about a 180° thermostat. They said that 180° is a perfectly acceptable temperature, but higher temperatures deplete the additive package and break down the fluid faster.

 

Did another ck.
Passenger side radiator and cap 155.
Drivers side 85.. way cooler.
Trans cooler 100, after a few min down to 80... Cools off really fast.

So the trans side does run much cooler , so it may not generate heat on the Tacoma. With the trans hooked up it would be hotter but not as hot as the engine side..
But I'm not running through the radiator, I also want to avoid the pink milkshake.
I thought about adding a thermostat but it runs fine, would just add parts and the fluid looks the best it every has and I when I'm off roading I push it. Burnt up the stock fluid in 7K, one day at the dunes pushed too long, it would get crazy hot.
I used to just run the stock cooler in winter But this year I just ran both and it drives the same.

I don't think you ever want the fluid over 170 if you can help it, so if I had a thermostat I would get around 130 but why would I want to build extra heat in the trans if it runs good. that would be like heating up the oil, you wouldn't.
And the trans pulls harder when it's cool, you can tell when it heats up, you loose a lot of power.
I don't think my set up runs too cool so I'm just going to leave it for now.
But if I towed a lot I may get a larger cooler.

 

The thermostats I was looking at start to open around 160° and fully open at 180°. I would like constant temps to promote less wear and to get the transmission hot enough to control any moisture that might accumulate. Constant temps help to minimize wear because parts expand and contract as they heat and cool. The majority of engine wear occurs at startup because the parts haven't expanded to their normal operating size. It's not as important in a transmission obviously, but the principle still applies. I agree that these transmissions do shift firmer when they are cold, but mine is often slower to downshift when it's cooler, it feels more responsive when it gets around 150° and up. If I could pick a temperature that I preferred to run at all the time, it would be 150°-160°. The truck adjusts the shift points and pressures using the temp sensors in the pan. All that said, after 10 years my truck is still shifting and operating fine with a mostly stock atf cooling configuration. The only thing I've changed is routing a remote filter mount and spin on filter after the radiator, but before the aux cooler. I'm gonna change my spin on filter soon and cut it open to see what all it has caught in the last 20k miles. I have a really strong neodymium magnet on the outside of the filter, so I'm excited to see if it has pulled any ferrous particles out of suspension in the fluid. I'm probably over thinking and over complicating this, but I enjoy it, so...

 

I would have used "D" for down hills and "4" for driving. This would keep the engine from revving up/heating up. Transmission cooler might be to small to keep temperature down. Also, you can route the transmission fluid two different ways.

 

What is your trans cooler part number?

I would be interested in getting rid of the OE cooler and swapping it out with your exact setup.

 

The return line is on top of the cooler? and enters the secondary cooler on the bottom correct...Mine is about 1/2" from the radiator and the fan pulls air nicely over it.

B&M 70268 SuperCooler Automatic Transmission Cooler , Black

https://www.amazon.com/gp/product/B000CIGE9G/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1

 

iv read this a couple dozen times

i dont ever doubt a svc mgr at a dealer will blow smoke up Ur butt ...........

at the same time i truly Dont Understand how 80% downhill
will overheat ANY transmission

MOST will disengage.........coast or at least ' traling throttle '
all 3 most definitely wont put a strain on a trans

no less 80% downhill would provide a respite if the 20% straight or intermittent
were a hard pull

if it did overheat
blew out fluid in the amount U observed

how much fluid was replaced ?!?!?!?

 

Today I installed a B&M Supercooler and Derale external Trans filter. Install went kinda smoothly. Completed a trans drain and the fluid was pretty brown. I struggled to get the truck into TEMP CHECK MODE. I think I'm going to do the same as you guys and monitor trans temps with my app to make sure I'm in the 115-130 degree range.



One question though, I don't have a

$160 ScanGauge - SG2 II Ultra Compact 3-in-1 Automotive Computer with Customizable Real-Time Fuel Economy Digital Gauges , Black , 5"

ScanGuage or UltraGuage, I'm using the OBD Fusion app through my iPhone and it shows two different trans temps. When driving they are off from each other about 10 degrees. Which one do you guys suppose measures pan temp? When driving uphill I see that A/T OIL TEMP 2 is always higher than A/T OIL TEMP 1.



I modified both gauges to highlight when both are in the Green (115-130 Degrees)

 

The lower of the two (and most stable) will be the pan temp. My 2007 Tacoma used to check at 97-115°F in temp check mode. I once put the truck into temp check mode with the jumper wire and then unplugged the jumper wire and then reinstalled and verified the check temp range with my Ultragauge.
As you can see, the temp light is not on at 95°, then comes on solid at 97° and remains solid until the temp reaches 115° at which point the temp light starts flashing to indicate that the temperature is out of range (too high).

 

OK, awesome. I'll change that bottom one to say A/T PAN TEMP. Thanks for that, that's exactly what I was wanting to know.

 

When I said “lower” I meant temperature, I was not referring to your picture. AT temp 1 in your case would be the pan temperature and AT temp 2 would be the Torque Converter fluid temperature. Sorry for the confusion.

 

Ah, ok. Thank you for clearing that up for me. Will Change those now. Thanks, man

 

There, fixed it so I now I know exactly what I'm looking at.

 

Just a small clarification, is the temp you are referring to at the pan or at the torque converter?

 

It doesn't matter what sensor you are gathering the information from
If your trans consistently goes above 220 on either sensor , you are limiting the life of your trans fluid .

 

Normally either temp is around 175 with the thermostat pinned open. On long steep grades I have seen torque converter temps go up to 230 for 10-15 minutes max and then immediately come back down below 200 when the grade flattens enough for the trans to lock up in 4th gear. I have decided to add an extra cooler so that even in these extreme cases the temp will stay well below 210 and hopefully 200. I will add a fan on a temp sensor if the extra cooler isn’t enough.