a/t fluid overheat

atalarico said:
I'm not trying to argue, and I very much appreciate your input, I'm just frustrated and a bit demoralized now. I've spent so much time and money on maintenance in the last 6 months and it just isn't letting up at all. I love my truck, but it's really ****ing testing my love right now.

What I'm seeing on this chart is that I was over 300F for about .2 miles. This chart is showing averages...which means I wasn't at an average of 300F if I only hit that once in 231k miles. I'm guessing if it smells burnt though, I should toss it if I want this tranny to go another 231k?

If I do another round of drain refills, and if I have some basic Castrol Dex/Merc in there right now (this), can I start draining and refilling with this and be OK (link)
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Dude, do yourself and your transmission a favor and do a full flush of your transmission. There's write-ups on it. I'm normally not a proponent of full flushes because I prefer the more frequent drain and refills of the pan instead but you completely cooked your fluid. It doesn't matter that it was only for a little while you were up at that high of a temperature. You broke down the fluid by taking it that high and now the lubricating properties are probably mostly shot. I wouldn't risk your trans by just doing a drain and refill. Start fresh and renew it all. I've heard the capacity of our transmissions is around 12 quarts.

You might be interested in reading through a couple threads I started that are related to this subject. Here they are:

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

If you decide to add an external cooler, I have a video tutorial that could help you with the install.

<iframe width="560" height="315" src="https://www.youtube.com/embed/2nVbwe2t2T8" frameborder="0" allowfullscreen></iframe>
 
I'm not a mechanic by trade, but I've always replaced fluid based on color and contamination. If the ATF fluid is still bright red (what does ATF smell like when cold anyway...) then I would not change it if it were mine. However, you will lose about 1 quart when putting in the cooler and will have to add may 1/2 quart more due to increase capacity so you'll be getting some fresh fluid in there anyway.
 
atalarico said:
Hey all,

First time this has happened in the 6 years of owning my 97 Limited. I was wheeling up a pretty steady and steep 3 or 4 mile trail (lower Crystal Lake in Colorado) and about 3/4 of the way there, I got the a/t oil light indicating that my transmission was overheating. While it wasn't slipping per say, it certainly wasn't delivering power the same way either. Something also definitely smelled like burning oil, but it could have been ATF. That being said, it normally smells like that since I never cleaned my engine bay of the built up oil leak after changing my valve cover seals.

I stopped my truck as soon as I found a flat spot and let it sit for 10 minutes. Started her up again, and when I was a few hundred feet away from where I was going it came on again.
By
Now, I'm guessing this had to do with a few things but I just want to makes sure I'm not missing anything:

1.) It was hot out, and I had just put a pretty hard highway drive on her to get to the trail to begin with, with barely any rest.

2.) I just replaced the transmission pan and it's possibly I put too much ATF in. I'm going to check tonight and siphon some out if needed (I have an oil extractor for my other car that I can top-side change with). I've heard too much can cause overheating too.

3.) I replaced the original rad with a Denso late last summer. The coolant was halfway between F and the L in the overflow reservoir. I didn't think that would be a big deal, but maybe? Also, it's strange because the last time I checked that (a couple weeks ago) it was closer to F. I figured since I changed my rad anyway, and I don't tow or wheel that hard, I don't need an external tranny cooler. However, I am going to check for milkshake later today just in case.

The drive home was totally fine. I had it in 4lo and 2nd and L for most of the descent, and it didn't overheat again. I stopped to air back up and let it sit for 15 minutes.

Thoughts?
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You mentioned that you might have over filled your transmission, can you elaborate on that? Did you check the level after you dropped the pan and refilled? What makes you think you might have over filled? I just installed an external cooler in series with the radiator and per the instructions said to make sure not to overfill as it can foam and risk overheating. Maybe that was your issue with in combination with everything else created a perfect storm for overheating.
 
A lot of really good advice in this thread. I had a very similar instance. My tranny fluid was getting really hot and I wasn't really doing anything but idling my truck with coolant flush in it. The Scangauge alerted me to the tranny temps. I was in the middle of replacing my radiator (a Denso from Amazon) with an OEM from Camelback. I saw the fluid color at this time and became genuinely scared. A grayish color. Still have a bottle of it which I'm sending to Blackstone. Just received the kit today.

I have since put a cooler in series with the radiator and have yet to see temps over 200. I'll take that. The real test will be my trip to Florida in a couple weeks.

My advice mirrors some already given. Look at the fluid. If it's anything other than clear red fluid, do a complete exchange. Get it all out and start fresh. Tranny hold 12 qts, but you'll need a couple qts extra.
Think about getting a Scangauge. It saved me once already and I've only had it a couple months.
Lastly, put a cooler in series with a Magnefine filter.
 
Did you use the AC at speed 3 or 4? then the compressor never turned off and heated the radiator. Initially I use 3 or 4 and after driving about 3-4 minutes, I'll lower the blower speed to 2. This causes the AC compressor to turn off frequently and then the radiator gets ambient air to cool faster.

Any external cooler has to run in series to the radiator cooler,never alone. Ford escape (Mazda tribute) trans cooler (fin type) fits perfectly into the front lower valence. I have one and still didn't get time to work on it. Currently, I have a hayden tube type cooler installed.

Yesterday, I drove 2 hours with a load at 75 MPH with AC at 2. As soon as I came home I checked the trans oil with IR temp probe, and it was 55 Celsius (131 F). The ambient temperature was 35 C (95 F)
 
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Interesting stuff about the ScanGuage. I think one thing we might be missing when we're talking about how inaccurate the temperature gauges are on our 4Runners is that it can also be inaccurate the other direction, no?

I'm resigned to having to change the ATF again, and I think I'm going to try to use my oil extractor down the dipstick/fill tube. One question I had was if I can shove the extractor tube down one of the hoses that go from the transmission to the radiator to get more ATF extracted? I know I'd have to have a bucket handy for the initial spill, but yeah, just trying to think outside the box a bit.
 
atalarico said:
I'm resigned to having to change the ATF again, and I think I'm going to try to use my oil extractor down the dipstick/fill tube. One question I had was if I can shove the extractor tube down one of the hoses that go from the transmission to the radiator to get more ATF extracted? I know I'd have to have a bucket handy for the initial spill, but yeah, just trying to think outside the box a bit.
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Like I recommended up above, I truly believe you are a candidate for a full flush having brought your fluid up to possibly 300 degrees (which is apparently the temp the idiot light for the transmission will come on at). Why risk the life expectancy of your transmission for the cost of some transmission fluid and a little of your time?

Here's a link to a good tutorial on how to do it.
Dropping Pan And Flushing Transmission

Don't bother with the part about dropping the pan and replacing the filter unless you want to do that too. Doesn't look hard. All you have to do is get a 5 gallon bucket, a section of trans hose and someone to help you. Looks pretty straight forward. Disconnect the return line from the radiator cooler (that's the connection on the driver's side of the cooler), add the section of trans hose to the fitting and drop it into the bucket you made graduated quart markings, and get a funnel ready to go in the trans dipstick tube. Have your helper start the engine, drain out a quart of two, stop the engine, add how much you drained out and repeat until the fluid entering the bucket looks clean. Our rigs hold 12 quarts, so somewhere after 12 quarts your fluid should be looking pretty good. The author of the write-up said he used 16 quarts but that might be a little overkill. But, I haven't done it yet so maybe you have to use that much to get clean fluid coming out the other end.

Good luck!
 
I'm by no means an expert in the matter, but I just finished a trip on my 4Runner of 370 miles on gravel, dirt, snow and roads that tested my Transmission & Engine. So that being said, i'll let you know quickly what I experienced on my trip where I did 260 miles first day and then hit the trail for 60 miles and throughout the trip did anywhere from 2k to 4k in elevation climbing up/down. Before my trip i did the bypass cooler and bought myself a SGII. I was so happy for this as I was able to use transmission shifting to increase my life of the transmission. I sacrificed speed a ton, to just go a little slower and have a lower temperature. Now it was 85 to 90F most days and as long as I watched my SGII and shifted and patience it did great. When we stopped for pictures, or lunch I would leave my vehicle running which would drop the temperatures by about 20-30F vs letting it sit not running which maybe got 5 F if I was lucky.

I know what you mean by the money sink in the vehicle and sometimes you have to, to save money down the road. Now I would do a complete flush as my experience has shown that those temps can basically nullify the oils ability. When the other vehicle lost the 5th gear in the transmission (its a manual) the oil was so thin and that was changed less than 5k miles ago. The vehicle see's a lot of hot weather and hard work so it's going to be stressed, but it was expensive synthetic oil so it should have lasted, but it was water basically due to the Transmission damage and heat.

So, when do you the trip again, go to 4L, L or 2 and be steady and take breaks even if its on a STEEP part. I would rather burn an extra 70.00 during the flush versus a new transmission. =)
 
Question on the flushing; so I'm in the middle of it right now, going a quart at a time (by myself). I'm Right around 10 quarts into my bucket and I'm noticing the fluid is looking like the brand new stuff (white bucket). In my case, since I burned it, should I do another couple quarts out? or should j reconnect the hose to the radiator and start adding back to the dipstick tube, starting the engine, shifting, and then measuring and adding as necessary?
 
And to add; if I drained about 3 or 4 quarts out from the pan into this bucket, and the bucket has about 10 quarts (according To my rudimentary graduation marks on the side), I've only flushed about 6 quarts through then? Is that enough?
 
atalarico said:
And to add; if I drained about 3 or 4 quarts out from the pan into this bucket, and the bucket has about 10 quarts (according To my rudimentary graduation marks on the side), I've only flushed about 6 quarts through then? Is that enough?
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I'd go at least to the 12 quart mark because that's the capacity in our rigs. If it's looking clean after that, you can probably call it good. I still don't understand the necessity to run 16 quarts through like the person who did that transmission write-up did.
 
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mtbtim said:
I'd go at least to the 12 quart mark because that's the capacity in our rigs. If it's looking clean after that, you can probably call it good. I still don't understand the necessity to run 16 quarts through like the person who did that transmission write-up did.
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Ok, cool! I reconnected the hose to the rad anyway and started filling, starting, shifting, checking dipstick, and it left me with 3 unopened quarts out of the 16. I'm going to pull the hose again and drain a couple more quarts, and then refill and call it. Does that sound like a decent plan to anyone else?

The stuff that came out first, for having been relatively newer, wasn't looking or smelling good, that's for sure. I'm glad you all convinced me to just do it the right way. Oh, and I got a killer deal on the castrol transmax too from Autozone. Guy felt bad they only had 1 gallon jug, so overrode the $7 on the qts to $5 and then ended up getting frustrated with the point of sale system and just giving me two for free. It was a sign!
 
atalarico said:
Ok, cool! I reconnected the hose to the rad anyway and started filling, starting, shifting, checking dipstick, and it left me with 3 unopened quarts out of the 16. I'm going to pull the hose again and drain a couple more quarts, and then refill and call it. Does that sound like a decent plan to anyone else?

The stuff that came out first, for having been relatively newer, wasn't looking or smelling good, that's for sure. I'm glad you all convinced me to just do it the right way. Oh, and I got a killer deal on the castrol transmax too from Autozone. Guy felt bad they only had 1 gallon jug, so overrode the $7 on the qts to $5 and then ended up getting frustrated with the point of sale system and just giving me two for free. It was a sign!
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If you already put 13 quarts through, I'd say you're good. You did the right thing and most likely prevented an untimely death for your transmission.
 
mtbtim said:
If you already put 13 quarts through, I'd say you're good. You did the right thing and most likely prevented an untimely death for your transmission.
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Sweet! Feels good. I've admittedly put this transmission through hell and back, and it's still kicking *intensely knocking on wood*.

Does anyone happen to know what the quantity differences are on the dipstick? For example, on the oil dipstick it's something like a half a quart between the low and full mark (correct me if I'm wrong, I just err on the side of less is more with the oil). I'm about a quarter of the length between the cool and hot mark on the transmission dipstick below the cool mark (engine running and shifted through gears), but I'm also parked on a bit of an incline, so I try not push it too much.

Also, I'm an idiot and didn't realize crush washers were different than split locks, and put a split lock on the transmission drain plug. I realized it after I saw the drain plug leaking a little, so I'm going to have to get a clean bucket to catch the new fluid when I replace that and just add it back in.

knowing-is-half-the-battle.jpg
 
atalarico said:
Sweet! Feels good. I've admittedly put this transmission through hell and back, and it's still kicking *intensely knocking on wood*.

Does anyone happen to know what the quantity differences are on the dipstick? For example, on the oil dipstick it's something like a half a quart between the low and full mark (correct me if I'm wrong, I just err on the side of less is more with the oil). I'm about a quarter of the length between the cool and hot mark on the transmission dipstick below the cool mark (engine running and shifted through gears), but I'm also parked on a bit of an incline, so I try not push it too much.

Also, I'm an idiot and didn't realize crush washers were different than split locks, and put a split lock on the transmission drain plug. I realized it after I saw the drain plug leaking a little, so I'm going to have to get a clean bucket to catch the new fluid when I replace that and just add it back in.

knowing-is-half-the-battle.jpg
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Just an FYI that I noticed when working on my transmission and getting the proper amount in. You need to drive it for a bit before the temperatures get warm enough to check the level on the dip stick. Turning it on and running through the gears will not give you an accurate reading. Going off my temperature gauge I installed, it took 10-15 min of driving around town to get the temperatures up. I can see now how people mistakenly add too much fluid because they fill the tranny up thinking it is at the hot level, but only driven around the block a time or two. When in reality the tranny temps haven't even warmed up.
 
Run 4 Fun said:
Just an FYI that I noticed when working on my transmission and getting the proper amount in. You need to drive it for a bit before the temperatures get warm enough to check the level on the dip stick. Turning it on and running through the gears will not give you an accurate reading. Going off my temperature gauge I installed, it took 10-15 min of driving around town to get the temperatures up. I can see now how people mistakenly add too much fluid because they fill the tranny up thinking it is at the hot level, but only driven around the block a time or two. When in reality the tranny temps haven't even warmed up.
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Oh, for sure! I only add to the cool level, and just a bit below that anyway since my driveway slope, even when it's on and running through gears in the driveway. I was going to drive it for a little while and then check on level ground before I consider it done. Thanks!
 
atalarico said:
Oh, for sure! I only add to the cool level, and just a bit below that anyway since my driveway slope, even when it's on and running through gears in the driveway. I was going to drive it for a little while and then check on level ground before I consider it done. Thanks!
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The FSM says to check to see if the fluid is in the "Hot" range when the transmission is at normal operating temperature which they say is 158-176. If you don't have a way to monitor your trans temp, just drive it for a while like down the highway for a few exits, come back and on level ground check to see if it's in the hot range. I would probably err on the side of being a little low rather than high and fill it to halfway between the upper and lower lines of the hot zone. If you drive it for a long time and get the trans up to a higher operating temperature, and maybe even have a scan gauge or the torque pro app to show you it's in the 160-175 range, I'd go ahead and top it off to the upper hot line if it's not quite there yet.
 
atalarico said:
Oh, for sure! I only add to the cool level, and just a bit below that anyway since my driveway slope, even when it's on and running through gears in the driveway. I was going to drive it for a little while and then check on level ground before I consider it done. Thanks!
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Awesome, sounds like you've got it taken care of. I just installed a temp gauge on mine and it actually isn't all that bad of an install. Since mine being a 97, I had to install one. It's nice to know what the temps get at. Good luck with yours.
 
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