People will continue to believe it even though Thermostatic Bypasses exist because coolers always cool....Converter Slip is the main heat source/generator.
Do automatic transmissions need to warm up?
- Thread starter Elkins45
- Start date
People will continue to believe it even though Thermostatic Bypasses exist because coolers always cool....Converter Slip is the main heat source/generator.
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- May 31, 2024
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Yes. If people like letting the car warm up a few minutes before heading out, that could be done idling in gear.
Shift it to R, or D.
The engine will be under a slight load, that will help the engine warm up a bit faster.
And the torque converter will also be at work, warming up the ATF.
On mine, the slightest movement of the gear selector effectively kills the engine's fast idle mode. It's been in the single digits or teens here for over a week and when I start my car, it idles at about 1800, then steps down to about 1200, before eventually getting to 650-ish (normal idle). But if I barely move the gear selector, it immediately steps down to below 1000. I guess it's as much a safety thing too though, in case you didn't have your foot firm enough on the brake and went into D at almost 2000 rpm.
Interestingly, if I pull it out of my garage and put it back in P, it will step back up in rpm but not all the way to 1800. So the ECU wants to fast idle within reason.
I use neutral to roll down the driveway, so technically, that's now up to 63 seconds of warm up time before I feather the throttle.
Having driven manuals for 40+ years I'm beginning to wonder if I can ever break myself of the habit of grabbing the shifter knob when approaching a stoplight...or of stomping the floor with my left foot before starting it.
'Course on the really old stuff mashing the clutch to the wood will just engage the starter
The car I learned to drive on was a Renault Fuego and I'm 100% it didn't have a clutch safety switch. Nor did my '82 Supra, as I recall. I never saw the problem either 'cause I was taught what a parking brake was. 1st gear isn't the parking brake.
The MHT10R80 in my 24 F150 powerboost does not like the cold the first 2 shifts into 3rd and 6th are sometimes rough till it warms up. Totally normal
My 81 Toyota truck had an override button on the dash that disabled the clutch switch. I was told it was supposed to be used to bump the starter in 4L to crawl across obstacles but all I ever used it for was to reach through the window and start in N.
I never really understood the part about crawling with the starter. Wouldn’t the engine just start even if it were in gear?
I remember the switch, they were carbuerated back then. There was also the occasional need to hold the brake while manipulating the gas to start, and the button helped there too. If it were just for rock crawling I think it would have prevented the engine from firing, which I do not believe it did, but it was there for the rare occasion one needed to do a pedal dance.
I recall my dad limping a ‘77 rabbit 4MT 1/2 a mile to the gas station with the starter in second. No issues resulted from it besides a filled gas tank.
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On topic. My 10R80 needs to idle 15 seconds to get the air out of the converter in order to grab a gear, especially if it has sat 24 hours. Or I just put it in gear and it gradually grabs but we are indeed moving sort of. Besides that, idling a couple of minutes does not make much of a difference at all in AT temps. In the morning departure from within the garage I:
- foot on brake
- turn key on so the little automatic memory module I installed has time to select Economy Mode
- release e-brake (which otherwise interferes with the above little module if I do that too soon)
- turn the key
- drop into gear
- release brake as soon as the trans grabs
- go
The only times I don’t do it this way would be (a) outdoors (b) a need to make a text or call before pulling out. I think other things will eat the transmission and engine in this vehicle besides cold weather start technique. My garage is around 38-40F this time of year.
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The last few tranny fluids I looked at, the pour points were pretty impressive. I believe the Motorcraft LV was -54 F. Not sure what some of the others are other than the Amsoil ATFs.
I would do as you mentioned. Idle till RPM drops then, drive normal. An idling vehicle will build more heat in the trans in gear than park, or neutral.
I would do as you mentioned. Idle till RPM drops then, drive normal. An idling vehicle will build more heat in the trans in gear than park, or neutral.
When cold, yes.
