Transmission Temperature

I was wondering what other trans temps reach while towing. I have a 2010 Tacoma TRD Sport w/ a tow package and a 26" travel trailer I pull at 5000 pounds. I recently drove in hilly terrain in AZ with outside temps between 95-100 degrees at elevations from 2500-4500'. On the freeway, my scan gauge read around 185-195 towing in 4th doing 65-70 MPH. Downhills cooled to around 180. However, pulling some hills (while not killing the trans) I stayed around 40-45 MPH and saw TF1 (pan temp) peak at 230 for around 5 minutes and the hottest TF2 (outlet temp) hit was 250 for the same period. On other hills, I cruised around 50 MPH uphill with TF1 around 205-210 and TF2 somewhere around 220, with the longest duration around 20 minutes. Its sits around 200 going around town in stop and go traffic. My truck has 48,000 miles on it. I've seen other forums says normal temp is from 180-220, but is that pan temp or outlet temp? And for how long? Does the fluid break cut its life in half the moment it hits 250, or is it an average? Is that 250 pan temp or any temp at any point in the trans? Thoughts?

 

That's about what I see in the Sierras towing a travel trailer weighing around 5k lbs loaded

 

Mine sees the same. Seems high to me.

 

For reference, I put my scan gauge in my 2014 Camry as we drove from AZ to CO. Surprisingly the trans never went below 199 after it was warmed up. On the freeway at 75 MPH, it stayed around 205 on the flat and 212 on the hills. It was 90 degrees outside. This was surprising considering it is just a car. Maybe these newer transmissions run warmer than we think.

 

I towed a 2000 # pop up to the mountains in August. I also have both trans temps up on my scanguage.
The highest I saw was 212 converter / 194 pan @ 20 C ambient - at 65 kph at the time (ambient was cool since the pass we were climbing is 2080 meters elevation).
Considering my trailer is less than half the weight and the ambient was 10 C hotter for you, I think your temps are right inline.
FYI - norms on level highway were 158 / 154 @ 21 C - at 110 kph on cruise in drive.

 

Thanks for the replies. Driving the Camry again, it actually hit 240 going up a mountain pass at normal speeds. I think they just run warmer.

 

Lets have a peek at what transmission coolers do
TRANSMISSION COOLERS
If you do not have a transmission cooler on your truck and you plan to tow or haul heavy loads or you are in heavy stop and go traffic and use 4X4 low a lot , consider purchasing a cooler . The cooler thats built into your rad is designed to cool the transmission with the weight of just the truck by itself .When you are in 4x4 low , your torque converter is usually in the stall stage and creates a tonne of additional heat .You dont have much air flow going through your rad when you are in low range 4x4 .
160 - 200 are considered normal temps providing your engine radiator is functioning properly . If your engine overheats , your transmission will also overheat
Normal fluid temperature in transmission to be 175 deg. F.

Rate of oxidation to double for each temperature increase of 20 deg F above normal (175 deg F). As oxidation rate doubles, useful life of fluid is cut in half.

At 175 deg F life is 100,000 miles
At 195 deg F (20 deg above 175) life is 50k miles
At 215 life is 25k miles
At 235 life is 12k
At 255 life is 6,250
At 275 life is 3,000
At 295 life is 1500
At 315 life is 750

At temperatures much above 300 deg F the metals in the transmission will tend to warp, twist etc. high temperatures causes the formation of varnish deposits which impair or pre vent transmission operation.

At a fluid temperature of 415 deg F fluid life is 30 minutes!

Source: Empire Lubricants Inc.
Consider a scan guage http://www.amazon.com/ScanGauge-Comp.../dp/B000AAMY86
Here is the best information for the scan guage http://www.tacomaworld.com/forum/2nd...-pressure.html

Ultraguage is now offering transmission temps http://www.tacomaworld.com/forum/2nd-gen-tacomas/318340-ultragauge-transmission-temp.html

You could also use the Torque app with an Android phone as a cheap alternative to watch your temps http://www.tacomaworld.com/forum/per...d2-reader.html

This is how Low Pressure Drop technology works::
When Automatic Transmission Fluid (ATF) is cold it is viscous. The unique Tru-Cool design allows the colder, thicker ATF to flow more efficiently through two open bypass channels positioned at the top of the cooler. As operating temperatures increase, the ATF becomes hotter and thinner, It's then directed through the core where it is cooled. Tru-Cool's highly efficient cooling technology combines improved protection against lube failure with optimal heat transfer.
http://www.amazon.com/Long-Tru-Cool-.../dp/B005XZXB1M
Long Tru-Cool Oil Coolers offer advanced cooling protection for many towing applications. The advanced technology out performs TUBE & FIN Designs, Delivers up to 15 times less flow restrictions, 30% more cooling delivers maximum heat transfer, Self-Regulating for maximum lube flow protection through start-up, varied temperatures and driving conditions, heavy loads and towing.
Here is Toyotas fluid flow guide ...Look at page 8 on this PDF http://www.toyotatundraforum.com/pdf/A750E.pdf
And here is a guy who recently installed a cooler correctly http://www.tacomaworld.com/forum/1st...agram-pic.html

cooler and fan install http://www.tacomaworld.com/forum/2nd...n-install.html

 

Thanks for the info. I'm still skeptical of Empire Lubricants' temps and fluid life because my stock Camry runs at 210 on the flat freeway in normal temps.

 

210 is a little warm . Are you sure your radiator in your Camry is functioning properly ? I believe your thermostat on the Camry opens at 180 .
Because your engine cools the transmission , I think your transmission temps are a little too high
The study that Empire lubricants performed is identical to many other studies . Its just the literature I put together and used Empire,s study in my posting

 

Yep, scan gauge shows water temps between 175-184 on the freeway. I just drive up to Sante Fe in 75 degree weather, the water temp stayed around 180 and the trans temp was between 200-205. It's a 2014 Camry with 35,000 miles.

 

I know this is a 2nd Gen Discussion and I'm a 3rd Gen guy (first post) but I wanted to link another option for a cooler and a couple of cool applications from my days running a 3/4 ton Cummins. The guys in the south west desert huck diesel trucks off of dunes have some serious cooling needs. They tow 12k lb. toy haulers as well and have the same problems with stock cooling in their diesels that we do in our Tacos. Setrab coolers (Part No. FP920M22I-2P which is a 9 series 20 row, 16W x 6.35H X 4.38D cooler with 2, 12V 684CFM fans) have been used in all sorts of racing applications and they work very well as aux coolers. I bought one but sold the rig before I could fab up some brackets to install it. Some racers use these as diff coolers on their Vettes, others as aux oil coolers, and still others as trans oil coolers.

Here is an install thread (cummins forum) with some pics on the rear cage of a desert toy, and also mounted under the front radiator, parallel to the ground.
Here is an install thread on with some pictures of a guy that installed it behind the transfer case.

The cooler is going for just under $500 on pegasusautoracing which is may seem steep but I hear good things and will be installing one of these on my Taco in the near future. If the things work for NASCAR and pro circuit guys it'll hold up for me. I'll be sure to post pics when I pull the trigger and I'm going to run it in series with the stock cooler. *Note: I have no financial interest in this company or the product, just sharing information I spent hours researching several years ago for my diesel build.