Did i cook my transmission?

2010 Tacoma TRD OR Automatic 135k miles

- So i was towing a boat (2200 lbs) up a very steep and long gravel grade back road. I was in 4x4hi and had the shifter selected to 'L'. About halfway up i noticed the red A/T Temp light was on, so i immediately stopped the truck, placed it in park and turned it off for 10 minutes. When i started it back up, the light was gone and i was able to drive the boat home the additional 250 miles without issue. Ill be getting a transmission cooler before towing again. But my question is, what other steps should i be taking? Do i need to replace the transmission fluid? What possible damage if any could have been done by getting the transmission so hot?

Thanks,

Edit: I dont see any oil leaking under transmission and the coolant is between low and high in the reservoir. Outside temperature was 70

 

If you have never replaced the fluid you should anyway. If you have, open the fill plug and stick a paper towel in there to wick some on the towel. Does it smell burnt? Is it still red or is it brown?

If you want to play it safe, replace the fluid.

Lots of threads on tranny fluid, when to replace, how, and how to tell if it is bad.

BTW, 10 minutes isn't very long, should have let it set for 1/2 to an hour.

 

Heat kills tranny fluid, replace the fluid before you have to replace the tranny.

 

Something ain’t right. Towing 2200 lbs in L in 70 degree weather should not have over heated your tranny even n a long steep grade. If you were towing in D and the tranny kept hunting gears then maybe it would over heat. In any event you need to replace the tranny fluid.

 

That’s what I think too. Could be low fluid maybe but in a well running transmission that should not have happened

 

Thank you all for the reply's. I had the fluid flushed/refilled 15k miles ago when i did the 120k service. I just checked the AT oil and it was pink/red and did not smell burned. I did find it odd I had to use almost the entire length of paper towel to shove in there to get a reading (its currently parked with the nose slightly down) is that normal?

At this point since its overheated i need to replace and not flush/refill correct? If so, Ill probably just do it myself this time as it looks fairly easy.

 

Get an add-on tranny cooler. Install the tranny cooler and do a drain/fill at the same time.

 

Is it not a good idea to do them separately?

 

That fluid looks fine...I wouldn’t do anything. Just drive your truck and enjoy it.

 

Wont be an issue to do them separately. Just easier process because you wont have to do a top off when you put the cooler on.

 

Sure if you like extra work but something still ain’t right. Don’t you wanna find out why it overheated performing such an easy task?

 

If its a TRD off road should have the tow package good for 6500 lbs and a trans cooler running in the radiator drivers side (just a coiled tube inside allowing the coolant to drop trans temp). So if your radiator temp was above normal due to load, grade, towing, and first gear that might be it and no worries. Done your coolant flushing the block and opening the 2 lower engine block plugs in the last 50k miles? If the truck was getting pretty hot then also look at cap and thermostat.

 

Absolutely, I stated in the original post i was going to add a transmission cooler before towing next. I was just under the impression that when the light comes on, oil has reach in excess of 300 degrees and that its life expectancy is now a few hundred miles based on this thread. Based on that i assumed it was better to replace oil this afternoon, and add the cooler when it arrives in the mail.

 

No, the trans will go into safe mode first.
But change the fluid and replace with a good synthetic.
From now on drain the pan and replace every 2 years... About 3 quarts in a 12 quart system..
Add a trans cooler....

Problem solved...

 

Oh so you don’t alteady have the standard cooler that comes with the towing package??

 

Maybe the fluid level is low? Do a fluid level check at the very least, probably a drain and fill with fluid check.

 

Even though the ATF may have have a red hue to it, the heat likely burned off the additive package ingredients. As long as there are no metal flakes in the fluid, you can do a full flush. If you did a drain/refill, that only replaces about 20-30% of the fluid. If you are towing, Toyota recommends a flush (not a drain/refill) every 60K; I would probably do it sooner if you row regularly and/or live in the "hot" states.

 

^^I agree here. If the A/T Temp light came on, the fluid additive package is cooked, even if it looks ok. Color of fluid is never the best indicator of service life (if it was, you could just eyeball your motor oil and services like Blackstone wouldn't exist).

Additionally, I wouldn't worry about there being a problem as indicated by others. 1st-3rd gear doesn't lock up the torque converter and if the grade is long enough and you don't have a factory tranny cooler, the tranny could get plenty hot. It's been my experience that the factory installed cooler on the towing package is barely adequate for hilly driving even without a trailer behind the truck.

 

Why was you in 4wd?

 

I’m assuming this