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You're still slipping the clutches and everything if you need an extra cooler to keep temps down correct? So my point is the wear is still occurring regardless whether temps are in check or not. Opinions?
Isnt adding an extra trans cooler just disquising a problem?
- Thread starter The motor guy
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Heat in an automatic transmission doesn't come from "slipping the clutches".
Heat in an automatic transmission comes from shearing transmission fluid in the torque convertor and general friction in rotating and meshed components, especially during increased load.
Heat in an automatic transmission comes from shearing transmission fluid in the torque convertor and general friction in rotating and meshed components, especially during increased load.
Trans coolers are generally added to prevent wear and elevated temperatures from conditions like towing or maybe a snow plow. It's not usually added to fix a transmission problem other than heat from work.
Having said that, cooler is better to an extent.
Having said that, cooler is better to an extent.
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I had my transmission in 4th gear limp mode which means it stays in 4th gear. The trans temp went from 190-260 in about 2 miles, we can agree to disagree on that one. Anytime the torque converter is unlocked its slipping and creating heat
What it that chart form? 1975?
Correct... but the TC isn't a clutch. The TC can be unlocked and every friction in perfect working order--and it'll crank out heat like nobody's business if you keep the rpm around stall while under high load and throttle.
The TC can act like a clutch, and today has a clutch, but when unlocked it doesn't wear like a clutch, even when slipping. But it makes heat when slipping.
You are saying the same thing.
That torque converter shearing created the heat. It’s slipping. Not the band clutch for fourth. The torque converter.
I mean, a transmission is only expected to last 100,000 miles under optimum conditions? May that was the reality in the 70's.
If I were going to make a generalized statement about those charts, it would be.
Only applicable to 6 or fewer speed transmissions. 8/9/10 speed units are in general designed and built to operate at higher temps, up to 240 degrees on a regular basis.
My 10r80 is at 200 just tooling around town with no load, and up to 220 when I'm working it hard.
Only applicable to 6 or fewer speed transmissions. 8/9/10 speed units are in general designed and built to operate at higher temps, up to 240 degrees on a regular basis.
My 10r80 is at 200 just tooling around town with no load, and up to 220 when I'm working it hard.
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Personally I think they should last as long as the engine. 150-200k is too soon too need a transmission
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Let's ask GM.....whatever they do....we should do the opposite!
My Chevy 6L90 has 252,000 miles ( knock wood) and has a factory aux trans cooler shaped like a mini radiator as well as the line that runs through the bottom of the main rad. It has done it’s fair share of towing a 9,000 lb trailer. If one is towing I would recommend the aux cooler.
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Or Chrysler
The Xterra in my signature has 393,000 miles and the transmission has never been touched except to change the fluid. The TC locks in 5th, and does a semi lock up thing in 4th. If you click off OD it will then lock fully in 4th.
My Toyota 8 speed TC locks in every gear. My guess is the trans will last forever but the TC I think might be problematic. We shall see.
Everything I have read says ATF starts to varnish at 240F? Maybe the new formulations are better but I always thought you wanted to keep the trans temps below 200 with maybe the occasional foray into the 220F range when using it hard?
My Toyota 8 speed TC locks in every gear. My guess is the trans will last forever but the TC I think might be problematic. We shall see.
Everything I have read says ATF starts to varnish at 240F? Maybe the new formulations are better but I always thought you wanted to keep the trans temps below 200 with maybe the occasional foray into the 220F range when using it hard?
Only speaking from 10L80/10R80 land (And other versions of the 'US' 10 speeds). These are designed to operate from about 200-240 during regular use, the fluid is formulated to allow that. Not sure what the upper limit to the ULV fluid is, perhaps @MolaKule could shed a little light on that end.
