My information comes from first hand experience over the past 33 years in engineering in the automotive industry....several of that specifically doing dedicated engine and transmission cooling testing. My background is not contained specifically to searching the internet for what all the other internet experts are feeding each other and regurgitating or reading lots of posts by people who do not know what they are talking about. The internet is one source for information...but take it with a large grain of salt in most cases.elwesso wrote:
Im not here ot argue, but Ive read many posts on other forums that say its necessary to keep the trans fluid below 200 degrees..... And thats with an external cooler, sine the stock "heat exchanger" will really heat the fluid..... And not cool it to any extent...
So the question remains... And its probably the difference between me, as the consumer, and you as the engineer..... You design the cars to get thorugh the warranty period, and we maintain them to make it past that.. So the question remains, will the transmission last 60-100k (worst case) under most operating conditions for the warranty period? Yes most certainly, but will it last past 100k and still provide the necessary lubrication, no.. Thats why you drain the fluid and clean the filters...
Bull**** to the idea that cars are designed to just make it thru the warranty period then die. Absolute, unadulterated bull****. Period. Engineers design cars and componetry for life spans of 150K to 200K or futher. I have never, in 33 years in the industry, EVER heard anyone say or insinuate that anything should be just good enough to make it thru the warranty period. Your comment is pointless in that regard.
The idea of the trans oil staying below 190 F does not even pass the common sense test if you think about it for 5 seconds. The trans oil coming into contact with the engine coolant in the heat exchanger that most all cars have will heat the trans oil up to at least the temperature that the coolant is at....so trying to keep it below the level of the coolant temp is pointless.
Do you really think that the heat exchangers in the radiators do not cool the oil???? Why on earth would all the manufacturers put them on all the cars if they were not working or needed....???....duh. Another common sense test flunked. The oil actually does get much hotter than you suppose and it really does get cooled by the heat exchanger in the radiator even when the coolant is very hot. Under high trailering loads, when the engine coolant is 250 climbing a grade in Death Valley the trans oil is entering the cooler at 280-300 or more and is getting significant cooling from the radiator based heat exchanger.
Engine oil and trans oil is perfectly fine at temps approaching 300 degrees F. 212 F only gets the moisture out of the oil for sure. Trans oil can live forever in the 240-250 range. 280 , even for extended periods, is cake for modern trans oil.
Tech from another forum[/quote wrote:Some pretty smart and well educated doctorate level engineers developed the oil life monitoring algorithm for engine oil and trans oil and they know far more about it than your internet experts. The trans oil life monitor simply does not react to temps in the 250 to 260 range and starts to degrade the trans oil life incrementatally as the trans oil temp gets above 280-300 for extended periods of time.
The trans is perfectly capable of running to 100K with no oil change. Trans oil does not get exposed to contaminants and byproducts of combustion like the engine oil does. Plus, it is lubricating completley different components under completely diffferent operating regimes compared to an engine. Trnas oil operates as a hydraulic medium primarily and lubrication and cooling secondarily. The trans is perfectly happy with a "life time" fill unless heavy trailer towing or livery usage drives the temp up.
Your idea of the life being designed for 60K and that you are going to increase it to 100K by additional maintenance is ludicrous. I doubt that you even know what is going on in the trans that you are "helping" by changing the oil... This area is the common turf of internet experts. All they know about a car is changing the oil so they pontificate on that subject to extreme and figure it is the holy grail. The maintenance intervals prescribed by the manufacturers is the correct way to go.
It is amazing to me the logic that goes into some of these discussions. Somehow the manufacturers/engineers were smart enough to design/develop/validate/manufacture the car/engine/components but the dumb asses were not smart enough to provide the correct lube and maintenance requirements. Forget the idea of the oil life monitor and the recommended oil. Those guys don't know what they are doing.....LOL LOL LOL
Internet experts abound. Take care in which ones you believe. Your chart is like motherhood and apple pie. Hard to argue with....but it is basically off by about 50 or more degrees based on Dex3 modern trans fluid. Certainly nothing would go wrong with the trans oil if it was kept at the temps in that chart....LOL....but if you could keep the temps at those levels you could probably get away with lard in the trans...or mozola cooking oil or something.
