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#21
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yeah im sure transmissions didnt like that high of temps. based on charts & other info ive seen 200 isnt too hot for most trans fluid or internals, factory T stats were 195 & most ran 5-10° higher than that, but the idiot light temps definitely were bad for transmissions.
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#22
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Goes to show, ignorance really is bliss.
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1979 Trans Am W72 400/4-Speed WS6 - Starlight Black Hardtop
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#23
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Trans cooler are in the cool part of the radiator so the temps are generally not a problem.
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#24
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Quote:
Obviously an auto trans doesnt cook "instantly" so its not of concern to many folks.
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather |
#25
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IIRC, Allison's guides call for no more than 250° sump temp and no more than 300° retarder outlet temp. If somebody's cooking at 200°, they might have other issues.
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Mike |
#26
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My coolers are in the bottom tanks. My cars are older.
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#27
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Quote:
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather |
#28
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I didn't say it was better or best, I said one of the biggest manufacturers of heavy-duty automatic transmissions in the world has no problem with 250° sump temps and 300° cooler inlet temps. Warranty is not affected as long as you stay below those thresholds (and the TCM is monitoring them, so they know if you exceed them).
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Mike |
#29
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Quote:
TRUCK transmission that has its OWN Separate COOLER anyway? Those temps Never reach 300... HEAT in an auto Trans is a KNOWN Enemy...
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather |
#30
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Possibly the fluid is the difference? Allison uses TransSynd, and I think they now have something even newer. I'm guessing Allison's clutches and o-rings are not vastly superior to the parts in our transmissions, so I wonder if fluid makes that much difference? I was merely pointing out that a major OEM allows 250° sump temps and covers that under warranty.
(And you can get 300° retarder out temps with a heavy load on a long grade, and that is still a permissible operating condition that does not void the warranty.)
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Mike |
#31
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Simply, and Factually put, transmission Temps OVER 200 degrees shorten the life of an automatic transmission. Not in years, in miles. Better fluids may help, but the soft parts just can't handle the heat forever, IN A CAR..
Also, most trucks that use a HD transmission have a Transmission Temperature gauge..
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather |
#32
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Can't argue with any of that!
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Mike |
#33
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Couple observations about transmission fluid temps. That chart posted is very old. Before full synthetic trans fluid was the norm. So for our old muscle cars using old Dexron or type F dyno oil fluid, staying under 210 degrees is wise. Full synthetic fluids take the chart numbers and you can ratchet up each category of failure 20 degrees minimum. My wife's Jeep has a trans temp sensor you can monitor while on the road. On a long trip recently in 95 degree weather through the mountains of West Virginia, I saw a high trans temp of 190 degrees and a highest coolant temp of 225 degrees F. The fleet of Ford Transit 350 HD vans I work on have no dipstick and no drain on the 10 speed automatics. We have several now with just over 300,000 miles on them. Per Ford recommendations, no fluid changes, no service, no checks. Look for fluid leaks. No leaks, keep on driving. They have temp sensors as well. Seem to run around 170-185 in hot summer weather. I have to say I am very impressed with the 10 speeds. Not a single failure yet. I am sure it will cost $$$$ when one finally croaks.
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#34
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Quote:
i have a 4th gen 4 runner & toyota also calls their WS ATF "lifetime" but it most certainly is not, the owners manual tells you to do a full exchange at 100k miles or 60k miles if used for heavy towing or other hard abuse like off roading. wonder if buried in the ford OM there is a stated fluid change at a certain mileage? toyota also has many trans/engines of this era going 300k+ miles, some on original ATF & they all use standard spin on oil filters ... theres a documented tacoma with the same engine/trans as 4runners that hit 1 million miles & was still going strong. modern vehicles are much better built than older or classic cars as far as drive train reliability. Last edited by 78w72; 07-23-2022 at 04:16 PM. |
The Following User Says Thank You to 78w72 For This Useful Post: | ||
#35
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Quote:
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The Following User Says Thank You to 70geeteeohh For This Useful Post: | ||
#36
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Quote:
More "speeds" in a trans reduces the torque load on clutches while keeping the engine at its set efficiency for application. Transmission "soft parts" Still do fail. Of Note, if you run a cooler thermostat , you will most likely run cooler Trans temps in a normal system, or a system that has a tank cooler And a separate trans cooler. Have done this on many cars, even stock ones. Towing 8K behind my HD up and down the Smokey Mountains with a 160 T stat in the Summer heat, my transmission only went to 180 degrees a couple times. So Putting a 160 T stat in a LS , or a LS converted car, can make a difference, AND still run in closed loop in the Wintah, with No codes.
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather |
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