Thanks DIYDad and toyomoho for this good information! I’m getting an education here and already know lots more about my Camry then when I bought it earlier this month.
DIYDad, that’s very disappointing about your Camry Transmission failure.
-How many miles were on it at the time?
-Had the ATF ever been changed before it failed?
Toyomoho: I attached what I entered to define the Custom PIDS for Pan and Converter Temps. Only the Pan temp works. The Converter temp always returns 0, all the time. Not sure why but maybe the Camry doesn’t support Converter temp or it’s not the right address? Any ideas?
So far I’ve taken the car out for a few 30 minute trips in mixed freeway and calm in town driving at ambient temps of 80 deg max F (It gets hotter than that here). Transmission Pan temps crept up to 194 deg F but I’m sure it will go much higher on longer trips with hotter conditions. Do you think there is any benefit to adding and in-line ATF filter and or a small Cooler?

 

I had close to 187,000 when it gave out on me. I had changed the fluid prior, much earlier in ownership I had the dealer change the fluid, then again about 4 months before it died I drained the pan and refilled. But I did not do an entire flush nor change the filter. That means I left about 2/3rds of the old fluid in there. That was enough. When you put 25k a year on it, and do steep hills both ways to work/home, you work that tranny and the fluid gets hot. Should have changed it sooner - it had probably at least 100,000 miles on it. Live and learn. I see it as an opportunity to learn how to replace a transmission, which I did

 

Thanks for the info DIYDad. Your experience suggests Camry Transmissions may be running too hot for good longevity in tough driving conditions. I say that also because I just got back from a 650 mile round trip to Las Vegas that involved some climbing in temperature. I monitored the Transmission Pan temp the entire way using Torque Pro. Ambient temperatures were over 100degF and my speed was generally 75-80MPH. I did not pull any load or have a top carrier. On the way to LV Temperatures reached a max of 111degF. When traveling on near level ground, Pan Temperatures were 203 to 220 degF. This increased notably going up moderate highway grades. There is a moderated climb that lasts for maybe 20+ mins where elevation increases by about 4,000 feet. I traveled about 80MPH and the Pan temp climbed to 239degF at the peak of the grade. Air temp for this climb started about 110degF but cooled to about 100 at the top. Of course the AC was on. It strikes me that this Pan temperature is too hot for the mentioned condition but I don’t have much to compare it to. The return trip was a little different. There was traffic so speeds were slower. The climbs were maybe a max of 2000 feet and more gradual. The highest pan temp I saw was 221degF and that didn’t last long. Otherwise the range for the return trip was mostly 200 – 215degF. I watched the coolant temps but not as closely as the transmission pan temps. I think the coolant rarely got above 190degF but made it to 205 or so during the big outbound grade. It also got as low as about 175. Seems like a wide variation for something that is thermostatically regulated. Here are some questions I’d like to solicit comments on:
1. Am I correct that for the mentioned conditions the transmission pan temperatures are high relative to other cars or are these temperatures expected under the mentioned driving conditions? My thought is most cars would be 20+ degrees lower for the mentioned conditions.
2. Certainly I don’t take trips like this very often and for most of my driving I expect the transmission pan temps to reach a maximum of maybe 200. Still my thinking is that adding an in-line filter plus an auxiliary cooler is a good idea for this car. Does anyone have any thoughts on this? Good idea or waste of time/money?
3. The transmission feels good on this car. Is there any chance the pan temperatures having reached 239degF on this trip were enough to damage any seals or o-rings??
Thanks for reading and for any comments.

 

You might be a victim of too much information as in now being able to monitor the trans fluid temp. Toyota obviously designed the trans to work at least as long as the warranty lasted and it uses synthetic fluid. Would guess even if the fluid was never changed it could easily make it to 100K miles.

Unless you are towing a trailer or always driving on hills in hot weather, the solution is to just change the fluid at 50K miles. Suggest doing this over installing a remote cooler.

Seals start degrading at around 270F.

As to the remote filter. This is a much easier job and will keep the fluid cleaner. When researching you will find inline filters systems and those using a removable can filter mounted to filter bracket. Get the can filter system.

Some manufacturers have issues with their filter mounting bracket leaking fluid due to casing porosity. Find a manufacturer having good feed back from users.

 

Thanks for this response!
It occurred to me that I was overly concerned primarily because these Camrys have a reputation for being reliable and that seems inconsistent with a conclusion that the transmission is running too hot.
Of course I’ve also poked around at what temperatures people are reporting for other models and in general it seems about 20 degrees lower than what I have. I also read that “varnish” (whatever that is) forms in the range of 220-240 and seals harden between 240-260 (found that here: Transmission Temperature Gauge: A Brief Guide - Transmission Repair Guy). Another link (http://hubpages.com/hub/Toyota-Camry...n-Fluid-Change) states in the 2nd paragraph “Fully synthetic ATF can withstand approximately 225 degrees before thermal breakdown.” Neither of those factoids provided much confidence in reaching 239degF on my trip! I was also reflecting on DIYDad’s transmission woes and wondering if a cooler would have saved his original transmission. I’d like to hear your thoughts on the above and thanks again for your help!

 

I would caution using the pan temp as the metric. I have had my Techstream connected reading the fluid temp and shot the pan with my temp gun, and they were several degrees C different (which would equate to even more spread in F). The fluid circulates so can dump some heat, but the pan has no good cooling mechanism. Not sure how great the air flow is around it.

My problem stemmed from the ATF being in the tranny for more than 100k miles, lots of trans high temp runs due to always climbing steep grades, and the oil varnishing. At some point something - gummed oil or such - began building up in the radiator cooling channels and eventually blocked the flow. This led to higher temps, and therefor faster degradation of already over used oil. I could not blow air through the radiator on full blast with my compressor - I had to reverse the direction (blow from the return side) to pop whatever crud was in there out. I spent time running air through it, but I feel I still have stuff lining those channels (running 18 quarts through the trans still produces darker fluid), hence my desire to put in a trans cooler (cheaper than a new radiator) and eliminate the possibility of re-crud ding my fluid.

 

I know that the Tacoma guys (my last vehicle) can get a live readout of the tranny temp with the Ultrascan. I don't see why it would not be available for the Camry. If you you look them up I believe they tell you what it can read for different vehicles.

 

I think I trust the Transmission Pan temperature I’m getting from the custom PID in Torque Pro. Transmission Pan Temperature from Torque Pro agrees very closely with ambient air temperature, coolant temp and the IR shot of the bottom of the pan when the car has been sitting in the garage overnight. I’ve also checked the temps from Torque Pro at medium and high temperatures when the car has been running. These compare usually within 1.5 degrees F with the IR shot of the bottom of the pan. I’ve done this more than a half dozen times to convince myself the good agreement is real. For this reason I think the numbers I’m getting from Torque Pro are accurate.
Toyomoho seems to think there is not a good reason to add a cooler if I change the fluid at 50k to 100k miles. He may be correct but I’m trying to understand why. For most of my driving conditions in mixed freeway and around town my temperatures reach a max of 200 degF but for the 650 mile trip I described in post #13 the pan temperatures were always above 200 and got as high as 239 degF during a moderate grade. Agreeably I don’t take trips like that very often but 2-3 times per 10k miles is expected.
What makes me nervous are references like those in post #15 that talk of fully synthetic fluid breaking down at 225 degF, varnish forming at 220degF and keeping ATF at or below 175 degF to achieve a fluid life of 100k miles. My fluid temps are rarely below 175 degF and sometimes exceed 225 degF. So I guess I’m a little confused as to why I should expect good fluid life when my ATF pan temperatures seem to be hot compared to these guidelines. I’d like to get a better understanding of this.
If you can shed some light on this please do and thanks for reading!

 

The only real way to determine the condition of oil is to have it analyzed by a lab.

For the majority of your driving the oil states below 200F. A synthetic oil reaching 239F on a hill for short time is different then the oil running at this temp constantly. This may be some fluid breakdown but all oil breaks down when used, the question then is just time.

If for the majority of your driving say in pulling a trailer resulted in high oil temps then you would need to do something. This is why manufacturers of pickup trucks and SUV's offer a tow package with a remote cooler.

Thus given your situation and concern cutting the change period to 50K miles should deal with all your concerns.

However if you want to install a cooler, that's your option. Suggest you plan ahead before buying the unit as it needs to mounted in front of the radiator. This requires routing the oil lines through the sheet metal in front of the engine which means finding a opening or making one.

DIYDad's issues may be related to the trans oil never being changed until it was too late.

 

Thanks toyomoho for this guidance. Your explanation makes good sense. Thanks DIYDad for the additional info on your transmission problem. I’ll probably put the remote cooler idea on the ‘back-burner’ for now, but I might keep an eye out for what is available. I’ll look forwards to seeing what DIYDad does for his cooler addition.
Thanks to all who offered guidance!