gearbox
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Driver School Candidate
Joined: Oct 2018
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From: Wales
gearbox
I am hoping to buy an RX400H 2007-2009 ish soon. Would like to know if all auto gearboxes are CVT, I have read some unfavorable comments about CVT and wondered if this is true of a Lexus.
Instructor
Joined: Sep 2017
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From: MN
Advanced
Joined: Sep 2018
Posts: 512
Likes: 151
From: Colorado
Toyota’s CVT is not like other manufactures transmissions. There are no belts that slip and give CVTs their bad name. I have a 2016 RAV and a 2018 RX450hl and they both are perfect and never slip or loose power. Toyota should never have called it a CVT. Internally they call it a Power Sharing Transmission (PST). Look at this https://parts.olathetoyota.com/conti...-transmissions. You can also look at these, which go into lots of detail on how the CVT works and how a hybrid works. They are long but, with patience, give good explanations
and
. The PST or CVT only has less than 20 moving parts vs traditional automatic transmissions.. They just don’t have maintenance or performance issues like a regular transmission. I for sure will never buy non hybrid car again
Instructor
Joined: Oct 2016
Posts: 857
Likes: 47
From: Oregon
Are you familiar with cars? Do you know how a "rear differential" works? It's the gear setup on the back axle of a conventional car that splits the power from the driveshaft to the two rear wheels.
Imagine a similar concept where your engine is attached to one shaft, an electric motor to the other shaft, and the wheels to the third shaft. Now you can drive the wheels with either the engine, the motor, or both. Or you can have the engine running but no wheels turning by just spinning the electric motor in the opposite direction.
This is what the Toyota hybrid system does. There is a very smart computer controlling everything, and the electric motor can be powered by a very big battery pack. Imagine you are driving at moderate speed. The engine is running, the motor is stationary. Now you mash your foot down on the accelerator. The computer knows that to get a lot of power out of the engine it needs to rev up, and for it to rev up the electric motor needs to be spinning in the reverse direction. So it delivers a current to that motor to make it do that. And every split second it adjusts that current and polarity and engine throttle position in order to satisfy your power needs at that moment.
So there's no "gear shifting" and there are no metallic belts and conical pulleys as found in a conventional CVT system. It's just a differential gearset and a very smart computer. It's brilliant. Very few moving parts, and no gear shifting.
Imagine a similar concept where your engine is attached to one shaft, an electric motor to the other shaft, and the wheels to the third shaft. Now you can drive the wheels with either the engine, the motor, or both. Or you can have the engine running but no wheels turning by just spinning the electric motor in the opposite direction.
This is what the Toyota hybrid system does. There is a very smart computer controlling everything, and the electric motor can be powered by a very big battery pack. Imagine you are driving at moderate speed. The engine is running, the motor is stationary. Now you mash your foot down on the accelerator. The computer knows that to get a lot of power out of the engine it needs to rev up, and for it to rev up the electric motor needs to be spinning in the reverse direction. So it delivers a current to that motor to make it do that. And every split second it adjusts that current and polarity and engine throttle position in order to satisfy your power needs at that moment.
So there's no "gear shifting" and there are no metallic belts and conical pulleys as found in a conventional CVT system. It's just a differential gearset and a very smart computer. It's brilliant. Very few moving parts, and no gear shifting.
Racer
Joined: Mar 2011
Posts: 1,817
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From: wa
It's PSD, not PST. Power Split Devise, as it splits torque and power between ICE/motor generator/wheel.
It is NOT a CVT. It was maimed CVT to be able to sell in the USA as, that time, they could not find a better niche to assign it to and it, likely, would have cost millions to create a dedicated one. So they slapped CVT tag onto it and ever since every few weeks we have a question - Well, how is that hybrid CVT? It is fine. After 8 years with 2 hybrids and in several hybrid forums, I have not seen a single complaint about PSD go bad.
It is very basic epicyclical gear set. Very similar to what you have inside automatic transmission. Understanding, how it actually works, is beyond normal human mind and, honestly, I don't think even its designers completely know what it can do. As it sometimes does strange things. Not bad, just strange - like going into electric mode at 60 mph, while it is designed to switch to ICE at 42/45, depends on year
It is NOT a CVT. It was maimed CVT to be able to sell in the USA as, that time, they could not find a better niche to assign it to and it, likely, would have cost millions to create a dedicated one. So they slapped CVT tag onto it and ever since every few weeks we have a question - Well, how is that hybrid CVT? It is fine. After 8 years with 2 hybrids and in several hybrid forums, I have not seen a single complaint about PSD go bad.
It is very basic epicyclical gear set. Very similar to what you have inside automatic transmission. Understanding, how it actually works, is beyond normal human mind and, honestly, I don't think even its designers completely know what it can do. As it sometimes does strange things. Not bad, just strange - like going into electric mode at 60 mph, while it is designed to switch to ICE at 42/45, depends on year
Pit Crew
Joined: Aug 2018
Posts: 210
Likes: 26
From: ME
It's PSD, not PST. Power Split Devise, as it splits torque and power between ICE/motor generator/wheel.
It is NOT a CVT. It was maimed CVT to be able to sell in the USA as, that time, they could not find a better niche to assign it to and it, likely, would have cost millions to create a dedicated one. So they slapped CVT tag onto it and ever since every few weeks we have a question - Well, how is that hybrid CVT? It is fine. After 8 years with 2 hybrids and in several hybrid forums, I have not seen a single complaint about PSD go bad.
It is very basic epicyclical gear set. Very similar to what you have inside automatic transmission. Understanding, how it actually works, is beyond normal human mind and, honestly, I don't think even its designers completely know what it can do. As it sometimes does strange things. Not bad, just strange - like going into electric mode at 60 mph, while it is designed to switch to ICE at 42/45, depends on year
It is NOT a CVT. It was maimed CVT to be able to sell in the USA as, that time, they could not find a better niche to assign it to and it, likely, would have cost millions to create a dedicated one. So they slapped CVT tag onto it and ever since every few weeks we have a question - Well, how is that hybrid CVT? It is fine. After 8 years with 2 hybrids and in several hybrid forums, I have not seen a single complaint about PSD go bad.
It is very basic epicyclical gear set. Very similar to what you have inside automatic transmission. Understanding, how it actually works, is beyond normal human mind and, honestly, I don't think even its designers completely know what it can do. As it sometimes does strange things. Not bad, just strange - like going into electric mode at 60 mph, while it is designed to switch to ICE at 42/45, depends on year
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