Do automatic transmissions need to warm up?

[Elkins45]

I know I ask a lot of ignorant questions but that's only because I'm ignorant. I've only recently owned a car with an automatic transmission and this is the first time I've ever driven one on 0º weather. Does an automatic transmission need to warm up before taking off in very cold conditions or is it OK to take off just as soon as the engine has warmed up a bit?

I'm assuming the transmission doesn't really start to heat up appreciably until you're moving but am I wrong? Does idling heat up the fluid very much? Should I treat an auto any differently that I did my manual vehicles all those years? Generally speaking unless it's absolutely miserable I just let the engine warm up until it comes off high idle then maybe 30 seconds more before taking off. Will this be hard on the transmission?

 

[dishdude]

ATF thickens at low temperatures and doesn't really warm up by idling the engine. Drive gently for the first few miles to warm things up.

 

[edyvw]

No. Start car and idle it as long as you need to buckle up, get thing in order and go slowly. Drive 2000-2500 rpms and keep HVAC at cold and only lowest fan speed so that your windows don;t fog up. Depending on a car, you should warm up fairly fast. If you crank up heat immediately, a. you won;t have any heat, b. you will slow down warm up.
ATF needs movement. Also, most vehicles have a heat exchanger between ATF and coolant. So, as the coolant warms up, it will warm up ATF, too.

 

[Rmay635703]

My old Dodge won’t enter overdrive or lockup until it’s driven a while in very cold weather.

The behavior seems to follow transmission temperature

 

[ctechbob]

'Need to'

Probably not.

But fluid being thicker can make them shift funky when they're cold since solenoids/valves won't be moving as fast as maybe the ECU expects, so it probably isn't a good idea to romp on it out of the gate until it starts coming up to temp.

 

[ctechbob]

My old Dodge won’t enter overdrive or lockup until it’s driven a while in very cold weather.

The behavior seems to follow transmission temperature

Likely done to speed warm up.

 

[RF Overlord]

Many cars, like mine, have a thermal bypass to route fluid around the ATF cooler until the fluid has warmed up a bit. Just drive easy for the first few miles.

 

[Lubener]

If the transmission is in good shape, no you do not need to warm it up. However, older transmissions which suffer from "morning sickness" where the hydraulic seals in the valve body harden in cold temperatures causing a variety of problems which go away when the fluid warms and the rubber seals soften up some.

 

[bullwinkle]

The Transit 10R80 will not shift properly & takes 7-8 seconds to go from drive to reverse when it's stone cold. I've resigned myself to giving it 4-5 minutes to shake off the cobwebs before trying it.

 

[Glenda W.]

IMO it depends on how cold. It’s -15F here right now and I plan on warming up my vehicle. If I just drove off at this temp the noises would be horrendous, not to mention my breath would literally freeze on the inside of the windshield.

 

[BISCUT]

In most temps I like to let my engine run for a bout a minute to circulate oil before heading out. It is -3F at my Ponderosa as I write this. These really cold days I warm it up more like 3-5 minutes. My street is an unimproved rural road that is steep and windy for about a mile and a half before I get to a traditional roadway. Since it's downhill it's a great low RPM way to warm up the fluids.

 

[melk]

I let it idle 1-2 mins as well, and will sometimes move the shifter between R N D a few times before taking off.

 

[eljefino]

Yes they do need to warm up, or at least like it a lot.

The Saturn TAAT was programmed to only have gears 1 & 3 when it's super frigid out.

 

[zzyzzx]

On a really high mileage automatic transmission in cold weather, I recommend idling for at least one minute before engaging the transmission.

 

[LWood]

Every time after startup and after letting the engine run for a few minutes when it's cold out,(below 32 degrees), I slip it into neutral for about 2 minutes and give it 1000 to 1200 rpms to get fluid pumped throughout the transmission.
The reasoning for that is many vehicles have a check ball in the output line and needs the extra bit of rpms to get the fluid moving. Many transmissions won't flow fluid in park,especially the older vehicles.
Larry

 

[ka9mnx]

Likely done to speed warm up.

It's done to get the cat(s) hot ASAP.

 

[thastinger]

You radiator has internal lines in which your transmission fluid runs through, this is meant to act as a temperature regulator...help warm the fluid in winter and cool it in summer.

 

[AdmiralYoda]

My 2021 GMC Canyon with the 8L45 doesn't have a thermostatic bypass valve so all of the fluid goes to the OEM external cooler all the time. Today it was -7F and I let it run for about 5 minutes while I got my stuff together getting ready for work. Even after 45 miles of highway driving the transmission fluid never got about 70F.

I take it easy for a few miles and after that its off to the races.

 

[Kira]

I take it easy for a few miles

In this old geezer's estimation, there's nothing wrong with going easy when you start out....even if you don't know exactly why.
Also, tires' flat spots (from overnight parking) are likely better off with slow driving instead of slamming them hard into the pavement.

 

[Hall]

The Transit 10R80 will not shift properly & takes 7-8 seconds to go from drive to reverse when it's stone cold.

I had that happen once in my Infiniti when it was about -10º F. As you know, temperatures close to 0º F aren't uncommon here and at those temperatures, things are better but you can still 'feel' some sluggishness.

I'm making sure to look at where people are from when they answer these questions too !