NiceWheels

I talked to my mechanic about changing the trans fluid in my GS 450h (156k miles). He said there was no way to check and no recommended interval from the manual. Is it not meant to be replaced? I know I had the fluid changed on my '13 ES 300h and the mechanics and the mechanics never said a word. Also, I always assumed there were two transmissions, one for the ICE motor and one for the E motor. Is there just one?

EDIT: left the actual issue out of the title

bclexus

There is a totally different transmission for the GS 450h, which is a technology-advanced CVT. It's so good it's like NASA designed and built it. The transmission fluid is not to be changed; never, ever... I bet it'll still be going strong in another 12½ years when your 2013 GS450h is 25 years old and considered a 'classic' in most states and pushing 400k miles.

NiceWheels

If it’s not broken, I won’t fix it.

bclexus

Right! Most parts work until they don't!

gripau1

Our GS450h 2020 was purchase second hand so I don't know the driving history even though it has less than 30k km on the clock when purchase. I tend to drive in severe conditions, ie in heavy traffic and towing a couple of motorcycles. All our vehicles we pay in cash as I'm allergic to car payments and don't finance or lease so we tend to keep them past the manufactures warranty. We usually keep vehicles for about 12-18 years and give the cars away to family members as their first car etc if they need them.

The hybrid transmission is simple compare to a 6/8/10 speed torque converter or dual clutch transmissions. The hybrid transmission uses planetary gearsets and a couple of electric motors which keeps them simple and reliable as there are no clutches, valve bodies or torque converter which tends to fail in transmissions or TCM bath in oil. Heat is the main cause of the trans additive fluids breaking down. When the fluid additives breaks down the transmission will fail quickly as the fluid is no longer doing its job and you get thermal runaway situation.

Like I said I drive and put my vehicles in severe conditions for long periods of time and for piece of mind I service the transmission myself. Below is how I did the DIY transmission service but DO IT AT YOUR OWN RISK AND I TAKE ZERO RESPONSILIBTY FOR ANY DAMAGE YOU DO. Its your vehicle do what you want to do or not do with it.

I'm not here to argue the definition from the factory of what "fill for life" really means but if you want to know the procedure to do a transmission change here is the process below. Its not hard to do the transmission service and its not rocket science.

https://www.clublexus.com/forums/hyb...id-change.html

NiceWheels

I really appreciate you sharing that post. My spark plug, MAF/MAP cleaning, and trans oil are the last maintenance items on my list.

gripau1

Budget and replace a set of ignition coils while you're at it.

Lwerewolf

Coils O_O

I keep one spare in the trunk (along with basic tools to fix my mtb and/or take off the intake cover to easily get to all coils), but my mk3 is >400,000km and is still on the original ones. That said, my mother's Yaris (2zr-fe 2006 or smt) blew one at ~220k-ish.

As for the transmission - "lifetime" depends on what "lifetime" means. I'd change the oil - following the proper procedure. Your call. Go on priuschat if you want even more flamewar discussions on the topic, but add a two-speed automatic gearbox (i.e. clutch packs, valve body & solenoids - good luck finding spares), a not-so-cheap auxiliary oil pump to our mix and a couple times more powerful car to the mix. Yes, you'll probably do this only once, even if you own it for 200k miles or something. No, I wouldn't skip.

Proper procedure for the 3rd gen (& the ls600h). Transmission supposedly hasn't changed for 4th gen 450h. Check techinfo just in case.

bclexus

I would never 'service' the eCVT by replacing the transmission fluid. Lexus/Toyota does not recommend ever needing to service it and their dealerships are supposed to decline all requests to change transmission fluid.

The eCVT in the Lexus GS 450h is very durable and an extremely reliable transmission. It has no clutch plates with a friction material composition that wears off, and there is no valve body like a typical automatic transmission.

Lwerewolf

I happen to see clutch packs to the left of MG2 in that pic that you shared.

bclexus

What you might refer to as a clutch pack or clutch plate is actually a clutch disc that is 'permanently' pressed (squished) against the pressure plate assembly in one unit. There is no friction clutch plates like a regular automatic transmission with clutch plates that require a friction compound composition because there is no friction - the clutch disc is permanently sealed to the pressure plate. That is why the GS450h eCVT is so buttery smooth - there are no plates that must contact a disc by way of friction. The eCVT has no need for friction contact. The entire transmission of power is done via gear sets connected to MG1 and MG 2 via gears!

View the below video starting at 3:08.

Lwerewolf

Yes, there is, and yes, it does.

ORNL Toyota L110f transaxle teardown (F = AWD, ls600h-specific)
Section 2.59 / page 42.

You can see what Toyota has to say about it in the link that I posted 4 posts up.

bclexus

An eCVT transmission has a 'non-friction' type clutch to synchronize two shafts (axles) that are temporarily spinning at different rates. This clutch plate has no friction properties, and is permanently pressed to its disc assembly and works with the flywheel to soften sudden changes, like when the ICE starts and stops. In an eCVT it is referred to as a torque damper. Beyond this, there is no friction surfaced clutch plates or clutch packs in an eCVT transmission.

Lwerewolf

Are you actually reading what I'm posting?

bclexus

Yes, I did read it.

Maybe you are not grasping what I have said, which is to pinpoint that the eCVT doesn't have or use friction compound (material) on clutches that wears off.

In the 1st Quote directly below I think you may have overlooked the inclusion or meaning of the word 'or' (meaning 'either' as in: 'in one or the other') in this context. The inclusion of the word 'or' was definitely not meant to characterize that the eCVT transmission doesn't have a clutch pack - - only that the clutches in a clutch pack have no 'friction surface'. I hope this straightens out any misunderstanding there may have been...


Yes, there are indeed clutches (a.k.a. clutch pack), however these clutches have no friction material to wear off like is used in a typical automatic transmission. The clutches in an eCVT transmission lock with the use of actuators, thus no friction material is needed for it to lock and therefore no friction material is ever removed to contaminate the eCVT transmission fluid.
p 40: Another view of the motor section is provided in Fig. 2.57. With the motor section upside-down, a valve
body cover is visible. Upon further inspection, the valve body is much like that of a conventional
automatic transmission. The Ravigneaux gear system requires the use of a brake and clutch mechanism,
and the valve body contains intricate pathways, solenoids, and passive mechanical pressure regulators
needed to supply oil of the appropriate pressure to pressure plates. These pressure plates are further
described shortly. Due to the nature of the clutch and brake system, the oil incurs significant heating and
is routed to an oil-cooler in front of the vehicle. An ethylene-glycol/water heat exchanger is located on
one side of the motor section and a coolant pathway passes to the generator section. The plate seen in the
right portion of Fig. 2.57 contains a resolver, oil pump, oil squirter, and bearing. The resolver is used to
obtain accurate measurements of speed and absolute position. The oil pump feeds the primary oil
reservoir and also feeds the oil squirter through a pathway which routes around the bearing. When the
plate is attached to the motor housing, the oil squirter focuses on the opposite end of the stator near the
Ravigneaux gear interface. Support is provided to the motor rotor by this bearing, and the ring gear shaft
is supported by the motor rotor shaft by means of a bushing.



p 41: The Ravigneaux gear section is shown in Fig. 2.58. An exterior-splined (male) hollow shaft extends from
the 30-tooth sun gear of the Ravigneaux gear system and connects to the interior-splined motor rotor
shaft. The ring gear shaft passes through the sun and mates with an interior spline of the primary output
shaft, which is also fixed to the carrier of the Ravigneaux system, which is a compound planetary gear set.
Two sun gears, visible in the right portion of the Fig. 2.58, rotate independently with the sun gear closest
to the motor (which has 27 teeth) fixed to the adjacent clutch interface. This 27-tooth sun gear meshes
with the larger 20-tooth planets of the compound planetary gear set. Smaller 20-tooth liaison planets are
fixed to and rotate at the same speed as the large 20-tooth planets. These gears are not utilized unless the
associated clutches are engaged by the corresponding actuator, as shown in the right portion of Fig. 2.59.
Only one of the two actuators is activated at a time. If the actuator in the left portion of Fig. 2.59 is
activated, the 87-tooth ring gear is locked to the chassis with the clutches, with the other set clutches
allowed to spin since no actuator pressure is applied. In this case, the compound planetary gear system
behaves as a simple planetary gear system with a stationary 87-tooth ring gear, three 28-tooth planets, and
a 30-tooth sun with the input from the motor connected to the sun, and the carrier serves as the output, as
it is fixed to the primary output shaft mating with the transfer case. This is equivalent to a gear ratio
which reduces the motor speed by about 3.9 times. If the actuator on the right is engaged, the clutch set
on the left is allowed to spin freely, as power is transferred through the 20-tooth planets and the carrier is
rotated due to the opposing force applied by the 27-tooth sun which is fixed to the chassis through the
activated clutches. This configuration causes the output speed of the carrier to be only about 1.9 times
less than the motor speed, and is therefore used at high vehicle speeds. Also visible in Fig. 2.59 is the
mechanism used to lock the output shaft when the vehicle in placed in park. A rear-view of the
Ravigneaux gear section is provided in Fig. 2.60, wherein the splined shaft which interfaces with the
transfer case is protruding outwards. To provide a better overall understanding of the entire gear system,
it is shown in Fig. 2.61 with all components assembled in the upper portion and disassembled in the lower
portion of the figure. Note that this does not include the gears associated with the transfer case.