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Transmission "warm-up" ?


tmhtmh

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Here in the NE it gets cold. I've driven for 24 years and never really heard of warming up a transmission. Years ago we used to let the engine warm up for a few minutes, but at some point that was deemed not needed and maybe a bad thing to do.

Now, I have my first "expensive" vehicle and it seems unable to shift as well when a bit cold as it does after running for a few miles. I even read here that it may refuse to go into 4th gear until "warmed up". What is THAT?

Not being much of a "car guy", I'm wondering if it's unusual to have a poor performing tranny at 30 deg (not COLD by my standards, btw). My Honday Odyssey does not have this issue as best I can tell. Is it a toyota thing or specific to this tranny design?

Lastly, is this what is causing all the tranny problems we read about? Could warming it up a few minutes like in the 70's be a solution? Is thr tranny fluid too viscous (sp?) at lower temps?

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At least part, if not all, of what you are noticing is by design -- the car is staying in gear longer to help the engine warm up faster. Emissions, mileage and performance all suffer until the motor is up to operating temperature.

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All Toyota's will not go into overdrive until the coolant temperature begins to rise. It's not just a Lexus thing, my 1991 Toyota Previa does the same thing. The purpose is to promote faster warmup for improved fuel economy and lower emissions.

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Toyota's have had this delayed engagement of overdrive feature since they came out with their first overdrive automatics back in the late 1970's. One purpose of the feature is to reduce transmission and overall drivetrain component wear because wear would be accelerated if overdrive was engaged when these components and lubricants are stone cold. For the same reason, owners of manual transmission cars should also avoid using overdrive when the drivetrain is stone cold.American cars don't have this delayed engagement feature presumably because drivetrain durability isn't a priority with the American car makers.

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Although you don't say what year and drive type, I have this in my '05 330. Two things will keep it out of the OD; not having the engine warming up and keeping my foot into the gas, as in climbing hills. I have noticed that if I let up on the gas pedal a bit, approaching 45 mph, it will reluctantly engage the OD, provided that there is some warming of the engine.

Gary

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The Lexus is my wife's and I haven't driven it in months. However, I am fairly certain it will have a lockup torque converter. These will not lock until the trans reaches a certain temp, this is for trans protection. Hope this helps.

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