Anybody measured their ATF temperature? (1 Viewer)

e9999

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been fooling around again with temp measurements...

put a thermocouple on the ATF cooler hi temp line. (At least I hope that's the one! I used the top one of the 2 black metal lines that run horizontally under the DS side motor mount and forward along the oil pan edge. That right?)
Did a brief run and got around 145F on flat city roads with ambience at 65F or so, and a max of 165F going up a smallish hill. Went back down to 125F on the freeway at 55mph.

The FSM mentions ranges of 122-176F and 158-176F for "normal" ATF operating temperatures with the 343 trans.
Anybody measured theirs and knows what typical values one would encounter in town and while wheeling? How about when towing?
I'd like to try and figure out where I'm at and where I should be so I can keep an eye on it while towing in particular...


(oh, and where is the ATF temp sensor located, if you know?)

added: went up something like 3000 ft or 4000 ft at low speed (20 m ph or so) and it peaked at 195F or so (with ambience at 70F or so).
 
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I have done soem IR gun readings of the trans pan cant remeber what it was but the oil pan and transfer case were both just under 200, the trans was much cooler. hot summer day 35 mile freeway drive into work.

here is a pic of the temp sender from the LX450 transmission overhaul manual. loks to be in one of the cooler lines, I assume the out line,
Tempsensor.gif
 

e9999

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RavenTai said:
I have done soem IR gun readings of the trans pan cant remeber what it was but the oil pan and transfer case were both just under 200, the trans was much cooler. hot summer day 35 mile freeway drive into work.

here is a pic of the temp sender from the LX450 transmission overhaul manual. loks to be in one of the cooler lines, I assume the out line,
thanks, didn't see that one, will look again.
I may do a pyro reading too sometime
there is an ATF temp idiot light, isn't there?
 
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yes, IIRC from a recent discussion it comes on at a rediculouly high temperature. over 300F or something like that? basically a "you just spend a bunck of money idiot" light.
 
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while you guys are crawling under your trucks doing your temp readings -

do you think you can get a couple off of the transfer case and the F / R diffs too?

just touching them a couple times lets me know they get good and warm, but how warm?

and I would also be curious if you could do some sort of temp test running the truck with dino gear oil and then comparing to the same truck running syn gear oil?

maybe best test would be dino frt & rear, compare temps

and then (leave front on dino) switch rear to synthetic compare temps
 

e9999

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Rusty Phillips said:
while you guys are crawling under your trucks doing your temp readings -

do you think you can get a couple off of the transfer case and the F / R diffs too?

just touching them a couple times lets me know they get good and warm, but how warm?

and I would also be curious if you could do some sort of temp test running the truck with dino gear oil and then comparing to the same truck running syn gear oil?

maybe best test would be dino frt & rear, compare temps

and then (leave front on dino) switch rear to synthetic compare temps


the problem with doing measurements when stopped is that the parts probably cool down pretty fast and at different rates. For instance I climbed the hill, got 165F on the ATF at the top, and then went to park, and it was already back to 150 or so IIRC. Good cooler! That's why I do my measurements as a function of time while driving. I suppose I could epoxy a TC to the diff and do that. I'd be willing to try but the TC will get ruined. You cover the TCs, special epoxy, and the synth and I'll try! PM me for details.
I could do a run and then try to pyro the bottom elements but I don't trust pyro measurements much.


Btw, anybody with an OBD2 logger knows if the ATF temp is available through the OBD?
 
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I have the opposite effect. I put in a tranny temp gauge in my tranny pan. It normally reads 155F when towing on a straight grade. It might get as high as 180F when I am towing up a hill. However, it will approach 180F when I am idling in a traffic jam, for example heading to a toll booth. I put this to lack of air flowing over the air cooler. There are two coolers, and air cooler and one in the radiator.
 
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If the trans coolant temp is lower than the engine coolant temp leavng radiator then the radiator trans cooler will heat up the trans fluid.
 

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Some reading I did a while back said that the ATF fluid temp varies dramatically with driving load conditions and can spike up pretty quickly under load. When the torque converter is slipping there is a power loss and the power loss goes right into fluid temp. It might come back down quickly as well. Whenever you are moving slow and the engine speeds up you take advantage of the "torque multiplication" feature of automatic transmissions, but there is slippage and loss as well. That happens at standing start, at gear shifts, and possibly a whole lot more under 4x4 crawling over obsticals conditions.

To get an accurate view of this, I think the sensor definitely needs to be at the outlet of the transmission, and somewhat isolated from the surrounding metal so the thermal mass of the metal doesn't "low pass filter" the indicated temperature.
 

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We use a cool temp gauge called a GoTemp in my science class. They're really cheap, accurate, and hook up to a laptop. The software that comes with it is pretty good, and you can set it to plot temps at various intervals and graph it all out for you.

I haven't used it yet for anything on the cruiser, but it should be pretty good for what y'all are talking about.

http://www.vernier.com/go/gotemp.html
 

e9999

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The ATF cooler I know of sits in front of the main rad so the coolant temp should not affect it directly.

I don't know of an ATF cooler in the main radiator.
 
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e9999 said:
The ATF cooler I know of sits in front of the main rad so the coolant temp should not affect it directly.

I don't know of an ATF cooler in the main radiator.
Take a look at the tranny lines that go in and out of the lower radiator tank.
 

e9999

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yup, that's right, forgot about that one. I would hope that it is separate from the coolant area in the rad, though.

Interesting. So the 2 lines out of the trans must be split, each one to the main rad and one to the forward ATF cooler, then?

I'll remove the lower plates and have a look under there when I have a chance. Can't see a thing...
 
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e9999 said:
yup, that's right, forgot about that one. I would hope that it is separate from the coolant area in the rad, though.

Interesting. So the 2 lines out of the trans must be split, each one to the main rad and one to the forward ATF cooler, then?

I'll remove the lower plates and have a look under there when I have a chance. Can't see a thing...

the 2 coolers are in series, the one in the radiator was the standard option, the larger external cooler was part of an optional package that all cruisers in the US got AFIAK

what I dont knwo is witch one the fluid goes to first.
 
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e9999 said:
yup, that's right, forgot about that one. I would hope that it is separate from the coolant area in the rad, though...
The in tank trans cooler is immersed in coolant. That is the entire objective, to transfer heat inbetween the transmission fluid and the engine coolant. If the transmission is running hotter than the coolant in the bottom tank, it will be cooled off. If it is running cooler than the coolant in the bottom tank, then it will be warmed up. The latter is a good feature when operating in very cold weather.

The reason I mentioned any of this, is that it is necessary to understand how the trans cooling system works in order to be able to correctly interpret termperature readings taken from different parts of the system and while under varying load and ambiant temperature conditions.
 

e9999

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well, if one were to believe the FSM, the normal operating temp of the ATF would appear lower than that of the coolant. But if the ATF cooler is at the bottom of the main rad, it probably only sees coolant that has already been cooled down quite a bit so if the ATF goes to the main rad first, it may get cooled down there some anyway.

Should go check which cooler the ATF goes first. Not obvious. Could work both ways.


Anybody else has some numbers on this?
 

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