Dear Car Talk:
Ever since I purchased my Chevrolet Traverse LT, I’ve noticed that the transmission temperature gauge regularly reads around 212 degrees at highway speeds. The engine temperature gauge reads normal or even a little cooler than normal — even when it’s hot outside.
I checked with the dealership and was told that this is normal operating temperature for this transmission. I worry that as soon as my warranty runs out, the transmission will expire.
Does this sound normal to you? I am constantly worried, while on long trips, that the transmission will give out in the middle of nowhere. — Ramiro
Don’t worry, Ramiro. It’s much more likely that something other than the transmission will give out in the middle of nowhere.
Actually, your dealer is right. This sounds perfectly normal. Here’s how your transmission stays cool: Whenever your engine is running, the transmission fluid gets pumped into the transmission cooler, which lives inside your car’s radiator. As the transmission fluid passes through the radiator (inside those trans-mission cooler lines), it essentially gets bathed in coolant. Once it’s cooled down, the fluid is sent back to the transmission to keep doing its job.
And do you know the temperature of that coolant that cools the transmission fluid? It’s about 220 degrees. It’s the same as your normal engine operating temperature, which is in the range of 210-230 degrees. Since the stuff that’s cooling the transmission fluid is 220 degrees, there’s no way the transmission fluid can end up cooler than that.
Think about it this way: If you had the air conditioner in your house set to 68 degrees, and you left a pitcher of beer out on your kitchen table all day, there’s no way it’s going to ever get any cooler than 68 degrees, right? Though I’m sure you’d drink it anyway.
If your transmission fluid wasn’t running through that 220-degree coolant in the radiator, it could heat up to 350 or 400 degrees or more. And then it would cook itself and your transmission.
But it sounds like your transmission cooling system is doing exactly what it’s supposed to do, Ramiro. Hope that knowledge helps you cool off a bit, too.