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Discussion Starter #1
First, I could not find a way to search in this forum so I will just ask the question in the forum. As I understand it, 2016 and older HiHys use only the 67 hp rear electric motor for reverse and it has a pretty short duty cycle. That might be a problem for me when backing a trailer on muddy ground. Even with the tongue weight, the front wheels would have more weight on them and therefore more traction. And, of course, awd in reverse would be best. Are the 2017-2019 models like that, too?
 

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Will you, please, provide a source you got that idea from? That rear PSD is for reverse only? As what HiHy has in the rear is mini version of what HiHy has in the front - PSD, Power Split Device.
Rear engages when front slips. Then, they both work in unison. Reverse is FRONT PSD.
That said, I used my HiHy to move family winter of 2015, starting December and for about 6 months, as a property truck, literally, in partial wetland property. That enticed driving on snow, packed snow and minor ice. more so, HEAVY rain and grass and mud, pulling small loaded trailer. Well, few thousand pounds it was for sure. Zero issues.
Yet, we had multiple reports of HiHy shutting down when attempted to go up snowy hill and consensus was to turn off traction control. I forgot the science behind it.
Also, folks had issues pulling trailers out of water on slippery wet ramps. Same situation - traction control blocked movement.
That said, if you were to take chances on your particular surfaces, with trailer - I'd clearly suggest to go conventional route and buy a proper sized SUV with ICE. A Tahoe, for example. Very reliable, a tank, really, and pulls more than HiHy without any concerns.
Few bucks saved in gas is not worth frustration, in my opinion.
 

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Discussion Starter #3
No, I didn't say the rear motor was only used for reverse. I said that only the rear motor is used for reverse. There is just an electric motor driving the rear wheels through an open differential. The front wheels are not used for reverse. The rear motor is only used for very low speeds in both directions (8 mph IIRC). It overheats if it is used much. I am encouraged to hear that your HiHy worked well in snow and mud. Did you have special tires on it? The cold weather probably helped keep the rear motor from overheating. I still want to know if the front wheels are used for reverse on the 2017-2019 models. Here is a video of the rear unit:
 

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Discussion Starter #5 (Edited)
I went searching for the thing I read that gave me the impression that HiHys are rwd only in reverse. I remember reading this thread months ago and post 15 might be the one. It actually says reverse is electric only so it could be awd. Does anybody know for sure? And are the 2017 and 2018 models the same as earlier models in that respect? https://www.toyotanation.com/threads/towing-with-highlander-hybrid.1544842/
 

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2019 Highlander Hybrid XLE
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First, I could not find a way to search in this forum so I will just ask the question in the forum. As I understand it, 2016 and older HiHys use only the 67 hp rear electric motor for reverse and it has a pretty short duty cycle. That might be a problem for me when backing a trailer on muddy ground. Even with the tongue weight, the front wheels would have more weight on them and therefore more traction. And, of course, awd in reverse would be best. Are the 2017-2019 models like that, too?
No, both the front MG2 and rear motor operate the Highlander Hybrid in reverse. The ICE cannot add to the torque though so you only get a relatively weak reverse power from the system. This is true of all Toyota hybrids. MG1 is driven by the ICE and adds FORWARD torque to the driven axle while MG2 can operate either forward or reverse as can MG3 in the back of the AWD models.
 

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Discussion Starter #7
OK! Thanks for clearing that up. Generally speaking, electric motors have lots of torque at low rpm so not having the power of the ICE in reverse doesn't seem like a problem. Nobody needs to go fast or very far in reverse. But some do
 

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The only thing that concerns me is that when the traction battery is too low to provide full torque to both MG2 and MG3, the ICE must run and apply forward torque to the front axle to generate power to run the other two motors. So when the battery is low, reverse has even less torque than you would expect from two motor/generators running in reverse.
 

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2019 Highlander Hybrid XLE
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No, I didn't say the rear motor was only used for reverse. I said that only the rear motor is used for reverse. There is just an electric motor driving the rear wheels through an open differential. The front wheels are not used for reverse. The rear motor is only used for very low speeds in both directions (8 mph IIRC). It overheats if it is used much. I am encouraged to hear that your HiHy worked well in snow and mud. Did you have special tires on it? The cold weather probably helped keep the rear motor from overheating. I still want to know if the front wheels are used for reverse on the 2017-2019 models. Here is a video of the rear unit:
Wrong. MG2 in the front torque-split-device powers the front wheels in reverse as does MG3 in the rear. When the ICE starts, MG1 reduces the available torque at the front axle by the amount of torque being used to power MG1 as a generator, so when the battery is low, you have less torque in reverse than when the battery is full. Running the ICE always puts some forward torque into the front axle, more and more as MG1 produces more power to run the other two motor/generators.
 
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