700R4 temp monitoring

[oldsmoker]

you may have seen this, if not, please watch it guys. Very interesting!

http://www.youtube.com/watch?v=87J7bpHGAzg

[1Gary]

To be honest I don't know if the synthetic trans fluids act in the same way the oils do.What I mean there is if you have a engine with some miles on it,the synthetic oils will find a leak if one is possible.Got me thinking if you have a weak seal in a trans,the synthetic trans fluid would find it and result in a leak too.I know of one member here that swears by synthetics,but most of his stuff is relative low mileage vans.

[astroturf]

Great Vid O.S.

Marked as a favorite.

Jim

[brokenwrench]

There is a little bit of misinformation in the video. Transmission fluid does not burn up the transmission, the transmission burns up the fluid. Fluid is damaged when it comes in contact with very hot metal, this occurs when clutch plates spin on metal plates (steels). The usual cause of slippage is decreased hydraulic pressure, wear of hard parts, or extreme torque. Whether it is the clutch plates in the converter or the clutch plates in the case, the result is the same. Once the fluid is damaged, it losses its ability to transfer heat and it becomes heavily contaminated with clutch material and metal.

The video is obviously an attempt to showcase Amsoil oil as surviving the heat in the transmission. The usual range that transmission temperature gauges show are nowhere near the failure point of the fluid. The temperature gauge is only a reflection of the range that the fluid you are monitoring has changed. Damage is a product of the degree of the insult times time. Eventually the hot oil damages seals, not clutch pack steel plates, not clutch material. If you think the clutch material is damaged at 300 degrees try adjusting the clutch of a G-gas race car between runs when it is 450 degrees in the bellhousing. The clutch material is fine, it is the flywheel that discolours.

The point about the fluid hitting the exhaust and starting on fire is pointless. All oils have a flashpoint, it is not related to anything but a fixed physical property. Exhaust systems on race cars get very hot, glowing red is common and glowing white if a bit lean, these heats are far above the flashpoints of oils and will ignite any oil irrespective of the temperature of the oil when it hits the hot pipe.

Like engine oils, transmission fluids are not that functionally different. One of the more entertaining claims are those that claim the oil stays 20 degrees cooler. This is not a good thing, the ideal oil gets heated as close to the parts temperature as possible then sheds it in the cooler. An oil that does not heat up is failing to take the heat away. You will not see any studies showing temperatures exiting the transmission and then returning.

[MountainManJoe]

I believe that if this happened and you became aware of it in this manner (return line measuring) it may be too late for the transmission.

That's what I'm saying. I DID become aware of 110*C fluid (230*F) in my pan (which I think is only a bit warmer than return line temp). Transmission is fine.

you may have seen this, if not, please watch it guys. Very interesting!
http://www.youtube.com/watch?v=87J7bpHGAzg

Is there a point in this video besides Amsoil pumping up their own product?

[oldsmoker]

timelessbeing:

we are members of a forum where we all are at different stages of understanding, experience & knowledge, that was the point, the video was well received by at least one other member, does it need more justification than that?

I for one, learnt something from the video and shared it in the thought that somebody else may do the same.

[MountainManJoe]

No offense, oldsmoker. The gesture is appreciated, but my personal opinion is that it's a crap video. The only valuable lesson there, is that torque converters turn mechanical energy heat, and then they don't explain how. I have a deep dislike for product propaganda infomercials, and I think they are poor learning tools, because they are often loaded with absolute rubbish intended to get your money.

My favourite transmission explanation is this 1950's DoD production. Prepare to be educated!
[youtube]http://www.youtube.com/watch?v=leCEmJA0WsI&[/youtube]

[MrJames]

It may be a good idea to sum up some of the posts in this topic hopefully as follows:

I believe that we have 100% consciences that too much heat in a transmission is bad and some disagreement as to that too cold is also bad.

The amount of heat is directly related to several factors including load, speed, ambient temperature, etc.

The same score is as to whether to maintain or remove the original radiator cooler or maybe more accurately called a heat exchanger when an auxiliary cooler is installed.

The location of a gauge sensor is still being questioned.

I don't think it has been stated as to what the normal operating fluid temperature should be. I believe the range is 150F to 200F. I agree with the ideal of the stated 175F number.

I don't believe that the maximum sustained fluid temperature has been stated nor the temperature when the fluid has lost it qualities.

Please chime in with anything that I missed or should be included in this summary.

[MrJames]

I believe that if this happened and you became aware of it in this manner (return line measuring) it may be too late for the transmission.

That's what I'm saying. I DID become aware of 110*C fluid (230*F) in my pan (which I think is only a bit warmer than return line temp). Transmission is fine.

Timelessbeing

I noticed that you have started another topic that is similar to this one. I hope nobody minds if we keep this discussion here instead.

If you assume that there is a 10% to 20% cool down factor from the cooler(s) than a return fluid temperature of 230F translates into between an exit temperature of 253F to 276F. That is the "problem" that I am saying especially if this occurs in normal driving conditions.

That is why the outlet fluid line is more informative. I also believe that if measured from the pressure port it would give almost the same result.

[MrJames]

Does this chart seem correct ?

[MountainManJoe]

The chart is more or less accurate, but shouldn't let it scare you. For example, getting the tranny hot momentarily while pulling a boat up a ramp is not a big deal. Cooking it for long periods of time by climbing steep hills at high speed in hot weather, or towing in overdrive = bad

some disagreement as to that too cold is also bad.

I agree with brokenwrench on this one. It'll shift slower for a couple mins. That's all.

The amount of heat is directly related to several factors including load, speed, ambient temperature, etc.

Yup, many factors. Gear ratio and TC slip are a big ones.

whether to maintain or remove the original radiator cooler... when an auxiliary cooler is installed.

This is very straightforward. The rad cooler removes heat. That's what it's for.
Newton's Law of Cooling states that the rate of change of the temperature of an object is proportional to the difference between its own temperature and the temperature of its surroundings.

The location of a gauge sensor is still being questioned.

I say put it wherever it's the easiest, and then keep in mind what you are measuring. In my opinion, the outlet temperature isn't terribly useful. What you're seeing is the maximum fluid temperature being generated by the torque converter, and it cools very quickly after that. That hot fluid is not spending a great deal of time in your tranny. The return line is your lowest temp. Again, not terribly useful because it will be warmed back up as soon as it reenters the transmission. I think the internal temperature would be the most useful. That's what your tranny parts are being exposed to.

I noticed that you have started another topic that is similar to this one. I hope nobody minds if we keep this discussion here instead.

I was just fixing some images in a topic I started a long time ago, not trying to hijack your discussion.

return fluid temperature of 230F translates into between an exit temperature of 253F to 276F. That is the "problem" that I am saying especially if this occurs in normal driving conditions.

If the fluid is getting that hot in ordinary driving conditions, then there's something wrong with the transmission or cooling system. For short periods of time in extreme situations, it wouldn't bother me.

outlet fluid line is more informative. I also believe that if measured from the pressure port it would give almost the same result.

I think the outlet temp will be much higher. Also keep in mind that this port does not get constant fluid flow.

[MrJames]

I noticed that you have started another topic that is similar to this one. I hope nobody minds if we keep this discussion here instead.

I was just fixing some images in a topic I started a long time ago, not trying to hijack your discussion.

The OP is oldsmoker and I feel like it is everyone's discussion. Sorry if I implied that you were hijacking. I just believe that what everyone has said here is important and should be in one place for future reference. BTW I just noticed the date of your topic.

[1Gary]

I think overall the info provided is important.But the question I have is at what point does it go into info overload??.We could talk about the chemical properties of trans fluid and what makes one better than the other because of that and at the end of the day with proper monitoring the end user just wants to know at what point do I pull off the road to save my tranny??.It is certainly good to know all the facts about this topic and still the statement holds true to keep it simple stupid.It is just like a guy's car I straighten out afew yrs ago.He had remote dual oil filters,aftermarket trans filter,oil coolers,trans cooler,and all of them leaked badly.All that came about from reading that made his chances of having his car last longer and wasn't a high performance car at all.The truth is he put his car at a greater risk with all the leaks.So if we agree to give the advise at what temp is a good opportunity to pull off the road for my two cents that is enough to work with.

[astroturf]

A great read on the subject...

http://www.hotrod.com/techarticles/gene ... ewall.html

Enjoy, Jim

[MrJames]

I think overall the info provided is important. But the question I have is at what point does it go into info overload??..... the end user just wants to know at what point do I pull off the road to save my tranny??.......... truth is he put his car at a greater risk with all the leaks. So if we agree to give the advise at what temp is a good opportunity to pull off the road for my two cents that is enough to work with.

Good advice about simple Gary. My attempt to summerize was because I was getting a little lost myself. However, I do not see a near total agreement on all but a few points and not on the most important bottom lines.

I do believe that there is some agreement as to the pull over temperature being 230F. But measured from where ?

Now to add more jumble to this topic. I am including two photos of what I now believe I have inappropriately been calling the ATF Radiator Cooler. I don't know what vehicle they came from but I assume that this is a typical design.






I now believe that this design is more appropriately labeled as an ATF Radiator Heat Exchanger because it warms cold fluid and cools warm fluid to maintain a optimal temperature operating range.

Maybe timelessbeing will post his temperature graph here as well to give insight to the non metrically challenged.

Maybe this topic is best summarized again when there is more agreement and re-posted to a sticky.