Toyota Tundra ATF Question

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supton

supton

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Not sure what forum to put this under...

What should my Tundra run for transmission temp? I'm not sure where the sensor is, but I configured my Scangauge to read ATF temperature. Cold morning (25F) I saw 180-190F on my drive to work; but coming home I saw a peak of 222F, likely unlocked convertor, while climbing a hill to get onto the highway. Since I wasn't driving it hard, much less towing something, it seems very high.

I've only watched it but for a day, so maybe it's nothing, maybe it's something. I'm just wondering if anyone else knows what it does run at normally.
 
Originally Posted By: 229
I would be adding an external cooler.


Wasn't there a factory option for a heavy duty tow package that included an external cooler? I'm not sure if it was TRD or part of a regular package when I was building the Tundra using their online-builder website. Otherwise there is an assortment of aftermarket coolers to choose from.
 
Open the hood and look between the bumper and radiator to see if you have a trans cooler. I know it's standard with the tow package.

Edit: I believe this is a power steering cooler (the one behind the bumper). The trans cooler is built into the upper half of the A/C condenser.
 
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Yeah, that's what's bugging me--it has the tow package, hence a transmission cooler. Tomorrow I'll dig around under the hood and find it. I doubt it's been bypassed, but one never knows.

Could it be that my XGauge is reading convertor output temperature? I know nothing about transmission design, but I'd think that ATF from the cooler would go through the pump, through the guts and then to the convertor, not from the convertor to the guts.

Ironically, I don't think I've seen over 195F for engine temp. It likes to hang out around 185 actually.
 
Originally Posted By: supton
Yeah, that's what's bugging me--it has the tow package, hence a transmission cooler. Tomorrow I'll dig around under the hood and find it. I doubt it's been bypassed, but one never knows.

Could it be that my XGauge is reading convertor output temperature? I know nothing about transmission design, but I'd think that ATF from the cooler would go through the pump, through the guts and then to the convertor, not from the convertor to the guts.

Ironically, I don't think I've seen over 195F for engine temp. It likes to hang out around 185 actually.


There was a change in transmission cooler designs between 09 and 10 model years. Check out this thread (3rd post down talks about it): http://www.tundratalk.net/forums/tundra-...-package-4.html

If you look at the sides of the A/C condenser, you will see a gap about 1/4 of the way down. Basically the top 1/4 is the transmission radiator and the bottom 3/4 is the A/C condenser.
 
Your scan gauge is probably off. Hit the trans pan with a IR thermometer and see what you get. But you have Ws synthetic fluid in there so a peak of 222F is not that hot.
 
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You are over thinking it and trying to play engineer. Just monitor the analog trans temp gauge in your instrument cluster and if it stays within the normal range, call it good.

I am not 100% certain, but I believe the PCM for this truck will also throw fault codes and light if you trans temp gets anywhere near out of range.
 
Originally Posted By: Doog
Your scan gauge is probably off. Hit the trans pan with a IR thermometer and see what you get. But you have Ws synthetic fluid in there so a peak of 222F is not that hot.


I did not know WS ATF was synthetic. It doesn't say so on the bottle. I'd like to see where you got your information.

I believe ATF's are formulated to offer best protection and lubrication at 175F. Above 175F, they degrade faster and require more frequent oil changes. I have not seen a temperature degradation curve for WS though. It would be a nice addition to this forum if you have one.
 
Originally Posted By: INDYMAC
Originally Posted By: Doog
Your scan gauge is probably off. Hit the trans pan with a IR thermometer and see what you get. But you have Ws synthetic fluid in there so a peak of 222F is not that hot.


I did not know WS ATF was synthetic. It doesn't say so on the bottle. I'd like to see where you got your information.

I believe ATF's are formulated to offer best protection and lubrication at 175F. Above 175F, they degrade faster and require more frequent oil changes. I have not seen a temperature degradation curve for WS though. It would be a nice addition to this forum if you have one.


I had a data sheet on it. I can't find it.
mad.gif
But it is a Low viscosity synthetic AFT like DexVI and Amsoil. Which is why Amsoil will work in a Toyota trans with no noticeable difference in performance. Frankly, I don't think WS is as robust as Amsoil but I get it $3-4 a quart cheaper so I use it. But I change it every 50,000 miles.
 
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Originally Posted By: Hootbro

I am not 100% certain, but I believe the PCM for this truck will also throw fault codes and light if you trans temp gets anywhere near out of range.


+1 it should do that.
 
IMO that ATF temp is too hot for my liking. I would add another cooler inline to the one you already have. HOWEVER, if this trans is thermostatically controlled, it will be impossible to keep temps lower than that (if that is what it is set for), as it will not allow fluid to pass to the cooler until it reaches the thermostat temperature. Only way to get around this is to bypass the thermostat. Many fords will have it in the transmission lines themselves. Not sure about the newer tundras.

My race truck would only reach 175-180* going down the drag strip. This trans was behind a 800 hp diesel pickup.
 
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Well, that's the point--unloaded, not heavy acceleration, and it's hitting 230???

I'm not alone:
http://www.tundratalk.net/forums/tundra-...emperature.html

I forget if it is in that link or a different one where someone found that the gauge wouldn't indicate hot until like 257F. I did find a service manual, but for an AB60F transmission, which I don't think I have; anyhow, that transmission apparently won't do lockup in 3rd gear unless if the ATF is 257F or higher. (!)

I can't find the link, but I did find on one forum that someone saw it hit 215F, they immediately hopped out and hit the pan with an IR heat gun. It showed 179F.

I'm guessing the fluid temps I'm seeing is convertor output, and that Toyota wants them to be high. That said, I'm going to schedule a flush soon. I wonder if I could get a sample, or at least see a bit of it, to see what color it is really. That said, Toyota has sold a few of these vehicles, and they aren't known for breaking, nor are Toyota automatics known in general for breaking.

Please understand, if I were to read up on ATF temp for any domestic vehicle... Well, I have been, and hence my worries!
 
That wouldn't surprise me if the TCM/PCM wanted to the see the convertor temp output because it is the heat generator. So if the trans fluid temp exiting the converter is closing on 250F it then knows the fluid inside the trans is getting to the point of degraded performance.

That is more than likely why it won't lock the tc until it gets that hot to quell the heat.

See locking the tc is great for fuel economy but hard on the clutch in the tc itself and the gears inside the transmission. It could also lug the engine in high gear which is never good. This is what a few mechanics who just rebuild them have told me.

The tc in the Forester locks & unlocks frequently in 3rd/4th which is one the reasons Subaru says to inspect the fluid so often for severe service I bet.

Honestly I wouldn't worry much, the Forester has an over temp light for the AT, the TDI will do the same.

The 09A in the TDI usually hovers around 190F, a little lower in the winter for obvious reasons.
 
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Went and looked; definately has the large cooler in front of the radiator.
 
Cracked open the level check bolt; too bad I was on an incline and dumped about a third of a cup out. Definately not pink, more brown than than pink. But not black either. I found a DIY that goes over how to flush this transmission (well how to get out as much as possible in the driveway anyhow), I will probably do that at my leisure before too long. Not worried now that I have looked.
 
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