Transmission warm up

[BobT]

Did a quick search but didn't find this topic.

This question came up in conversation recently and I have wondered about this myself on occasion. After starting your car on a cold morning, is there any benefit to putting the automatic transmission in neutral while the engine warms up? Does this help warm up the transmission or does it make no difference?

I've figured it doesn't matter because the fluid is being pumped and this will warm it up. Would like more educated information than my backyard knowledge.

Thanks,

[Macgyver55]

Doesnt make any difference whether its in park or neutral the fluid is going through the same circuits in the transmission. The only difference between the two is that in Park, the parking pawl is engaged to keep the vehicle from moving whereas in neutral it is not. Its always a good idea, especially in this severe cold weather to allow your transmission to warm up a bit before heading off and go easy on the throttle for a bit too!

[Scott K]

The best way to warm up your transmission is to drive it, but when it is this cold out, I would start your car, let it warm up for about 5 minutes, then just drive slow until the car reaches normal operating temperature.

As for the question of shifting it in to neutral?

There is some truth to it, some transmissions dont circulate transmission fluid in Park or neutral, or is very minimal, so in these transmission, putting it in gear, would start the circulation of the fluid, to run the fluid through the radiator, to help heat it up. Most transmission, circulate fluid, even park, and in neutral, so for most cases, this wouldnt make any difference.

[Down2Earth]

The 99 Jeep Grand Cherokee I had needed the transmission in neutral to circulate the fluid.

[BobT]

Doesnt make any difference whether its in park or neutral the fluid is going through the same circuits in the transmission. The only difference between the two is that in Park, the parking pawl is engaged to keep the vehicle from moving whereas in neutral it is not. Its always a good idea, especially in this severe cold weather to allow your transmission to warm up a bit before heading off and go easy on the throttle for a bit too!

Agreed! It amazes me every time I see someone start their car and immediately drive it as if it is fully warmed up. Things are heating up, metal is expanding, lubricants aren't lubricating and in some cases not even flowing, and they are putting the coals to the drive train.

It sounds like the general answer is that it makes no difference but to be sure one should check with the manufacturer.

[Macgyver55]

The 99 Jeep Grand Cherokee I had needed the transmission in neutral to circulate the fluid.

I guess we are talking about different meanings of circulating. Anytime the engine is running the torque converter is turning, which is in turn spinning the transmission pump. This fluid has to go somewhere when it leaves the pump, and in neutral and park it bypasses all the gear circuits, so essentially, park and neutral go the same place. Either way they will warm at the same rate. Possibly you are thinking of "circulating" as fluid going to the transmission cooler in which case yes, some transmissions wont send fluid to the cooler when in park, but most still do.