For those with a trailer hitch?

You mean in previous to Gen4, the motor generators weren't cooled? Because the transmission fluid is what cools down the motors from what I've read.

 

There are areas where coolant carries heat away from the transaxle fluid. That has been the case since the beginning as far as I know. Some gen2 owners that did early transaxle fluid changes reported the used fluid being burnt smelling. Toyota also had a zero tow rating for the Prius globally until the gen4.

The gen4 got an additional cooling loop that pumps the transaxle fluid to an exchanger core in the radiator. This is how all automatic transmissions are cooled.

 

This is from a 2017 Prius Eco. Is it different than the other 2017 Prius mechanically/cooling wise?

From what it says, the transmission oil is going through a heat exchanger that is cooled down by the inverter coolant, not directly to the radiator. Only the engine and inverter coolant loops go to the radiator. But in a way, indirectly (through the inverter coolant loop), so does the transmission oil.

 

I assumed it was just like other automatic cars, but this way will result in the same effectiveness. The previous models had a point on the transaxle where coolant flowed by; the fluid stayed in the transaxle like a manual transmission. The gen4 pumped the trans fluid out of the transaxle to a larger exchanger.

 

This part of the video shows where/how the inverter/converter coolant loop flows through. Pretty interesting. Thanks for making me look it up. I hadn't seen this video before

 

Nope

 

It varies. How about yourself

 

Nope, you can't answer or nope it doesn't display the engine lifetime running time or mileage?

 

It does not display

 

Ok thanks, I'll stop trying to make it work then.

 

Gen 3 has this as well I think. On Gen 3 the portion of the radiator for inverter coolant is a strip along the top, maybe 4~5" wide. IIRC Gen 4 is similar, except the strip carrying inverter coolant is at the bottom.

Gen 2 I'm not sure about.

 

The inverter always had a separate cooling system with the its radiator part of the engine's. Pretty sure the fluid is the exact same coolant as in the engine side. It's separate because the inverter electronics can't handle the heat the engine coolant reaches.

I'm talking about cooling the oil/fluid in the transaxle. Automatic transmissions pump it out of the transmission case to more effectively shed to heat somewhere else. The Prius didn't always do this. IIRC, it was with the gen4 that Toyota started doing this. It was whichever generation got the 725kg tow rating in Europe.

 

Ah, ok; reading too fast.

 

When any lubricant gets overheated it breaks down. Damaged lubricant, including ATF, can't lubricate as designed, so then machinery breaks down and is damaged. The indicators are more than just the temperature, it is also time-at-temperature. If you stress and heat any lubricant examine it frequently and be ready to do more frequent lubricant changes.

Do you think European Primes have the tow rating because Europeans are mainly rule-followers? And Americans often aren't? We don't know why the U.S. Prime has a zero tow rating...brakes? Driveline? Frame (or whatever part of the unibody serves as a frame)? Tire load rating?

 

The issue here is that ATF is less heat tolerant than the gear oil usually goes into a manual transmission; some of those use motor oil. ATF also needs to work as an hydraulic fluid, which leads to compromises in other properties. The hybrid transaxle doesn't need a hydraulic fluid. It should have a gear oil. Toyota either wanted the ATF for better efficiency, or their manual transmission fluid wasn't compatible with the motors or other parts.

The Prime doesn't have a tow rating; just the hybrid got it. Assume the battery weight negated towing.

Posted this some time ago. The blog link is no longer good, but I copied the important bits.
Why Tow Ratings are Different in the EU vs. the US | PriusChat
tl;dr It comes down to different trailer regulations.
Europe loads the trailers so less weight is carried by the car than in the US. So lighter duty vehicles like small cars can tow more, but the trailer gets dangerously unstable as you approach 65mph. They also require trailer brakes at lower weights than most US states.
The testing standard for tow ratings now used in the US is also a hard test with the required speeds and inclines.