RX400h gearbox failure

[Rutlandlex]

Not my car thankfully but I was browsing Gumtree looking at RX's and found this one for sale.  The engine starts but it has no drive so I just wonder what that could be.  The only thing that I can think of is that there is an electrical issue causing a break in communication between the gearstick and the gearbox or the planetary gearset has broken.  I've never come across a failed gearbox on a 400h before so I thought that I would share it.

The car does appear to have a towbar on it albeit with no towball attached so maybe the gearbox could have overheated as a result of towing something heavy but again a very rare event indeed.

https://www.gumtree.com/p/lexus/2006-lexus-rx-400h-3.3-se-cvt-5dr-auto/1324610681

[Britprius]

2 hours ago, Rutlandlex said:

Not my car thankfully but I was browsing Gumtree looking at RX's and found this one for sale.  The engine starts but it has no drive so I just wonder what that could be.  The only thing that I can think of is that there is an electrical issue causing a break in communication between the gearstick and the gearbox or the planetary gearset has broken.  I've never come across a failed gearbox on a 400h before so I thought that I would share it.

The car does appear to have a towbar on it albeit with no towball attached so maybe the gearbox could have overheated as a result of towing something heavy but again a very rare event indeed.

https://www.gumtree.com/p/lexus/2006-lexus-rx-400h-3.3-se-cvt-5dr-auto/1324610681

It does sound as there is a serious electrical problem with it. The RX has two separate drive systems. One a standard hybrid dual motor generator system to drive the front wheels, and a completely separate electric only drive via a motor generator built into the rear differential with no mechanical drive linkage to the front system. The two drives have separate inverters "although in the same housing, and run from the same HV battery".
This could get very expensive very quickly, and the car is not that cheap to make it worthwhile. The seller would have to sell it as for parts only as there could be no guarantee even though he is a trader. If it was fixable cheaply I think he would have done it.

John.

[Rutlandlex]

Yes I think £3k is somewhat steep for it given that it could potentially cost £2k to fix.  It's impossible to say what the issue might be without seeing it but there are better examples out there with working gearboxes for those who are looking for one of these cars.

[The-Acre]

I went to see a car that this dealer had about a year ago and nothing inspired me to go for it.  His description didn't match the car at all I'm afraid, and I think his prices are high from what I saw. He often has older LS's that look poor.

[Lozsta]

Don't tow it away it will need to be on a car carrier (the manual specifically says not to tow the vehicle).

[Delphius1]

Hi,

The 400h has a CVT gearbox on it. Not the best for towing and the gearbox can be easily damaged by hard towing use.

The best gearbox for heavy towing is either a manual or an auto with a torque convertor. The CVT, DSG and similar modern automatics tend to not cope well with heavy towing use. For instance slowly reversing a big caravan up an incline, like you would manoeuvring a caravan in reverse up onto a drive. It can be hard on a manual clutch, let alone the modern semi-auto boxes (but at least on a manual you instinctively know when you're abusing the clutch and give it a rest... DGS gearboxes don't. The wet clutch DSG boxes fare a bit better because the oil tends to have a cooling effect, but the dry clutch DSG boxes have a habit of failing to pull the car on it's own, let alone a heavy trailer. CVT gearboxes can burn out belts and/or drums if pushed too far. A torque convertor box will just sit there spinning fluid around with just a moderate increase in heat.

Not knowing exactly how the motors on the 400h integrate mechanically and electrically with the drive train, I'd say walk away.

Although it would be handy to plug a techstream in to see how many error codes the transmission has. :-)

 

 

[Gliderpilot]

The 400h gearbox is whats known as an e-CVT, there are plenty of videos on YouTube as to there construction. There are no metal belts or slipping clutches in there and in fact there is no reverse gear, reverse is obtained by reversing the traction motor direction and using the Battery direct. The traction motor is constantly connected to the front wheels and power is mixed from the Battery and ICE via an epicyclic gear unit. The rear wheels are driven by a second traction motor/differential unit. I tow a 1700Kg caravan and have done ever since I got the car 5 years ago and it still performs the same as it did then.

[Britprius]

1 hour ago, Delphius1 said:

Hi,

The 400h has a CVT gearbox on it. Not the best for towing and the gearbox can be easily damaged by hard towing use.

The best gearbox for heavy towing is either a manual or an auto with a torque convertor. The CVT, DSG and similar modern automatics tend to not cope well with heavy towing use. For instance slowly reversing a big caravan up an incline, like you would manoeuvring a caravan in reverse up onto a drive. It can be hard on a manual clutch, let alone the modern semi-auto boxes (but at least on a manual you instinctively know when you're abusing the clutch and give it a rest... DGS gearboxes don't. The wet clutch DSG boxes fare a bit better because the oil tends to have a cooling effect, but the dry clutch DSG boxes have a habit of failing to pull the car on it's own, let alone a heavy trailer. CVT gearboxes can burn out belts and/or drums if pushed too far. A torque convertor box will just sit there spinning fluid around with just a moderate increase in heat.

Not knowing exactly how the motors on the 400h integrate mechanically and electrically with the drive train, I'd say walk away.

Although it would be handy to plug a techstream in to see how many error codes the transmission has. 🙂

 

As Glider Pilot above says the eCTV transmission has nothing in common to CVT, or other types of auto transmissions. It is more akin to the transmission of diesel electric transmission used in locomotives where the engine drives a generator, and this in turn powers an electric motor. No actual ratio changes take place.

I have a GS450H rear wheel drive only, and that is rated to tow 2000KG without any extra cooling. I also regularly tow a caravan of around the same weight, and have never had a problem even when restarting on a 1 in 5 hill. In fact the car will still move away while towing without the engine starting as MG2 one of the two motors in the transmission is rated at 186 hp with 203 ft lbs of torque at zero revs.

John.

 

[Rutlandlex]

2 hours ago, Delphius1 said:

Hi,

The 400h has a CVT gearbox on it. Not the best for towing and the gearbox can be easily damaged by hard towing use.

The best gearbox for heavy towing is either a manual or an auto with a torque convertor.

 

Towing may or may not have anything to do with it.  I was just pointing out that it appeared to have a towbar fitted so towing as a factor cannot be ruled out.  The oil cooler could be damaged for all we know and this could have LED to it overheating.  I have towed a caravan with mine and I would say that it is good for towing except for 2 things - one being the very high rpm's from the engine when towing uphill and the other being the hideous fuel economy.

Torque converter autos do have the ability to lock up in the higher gears for better efficiency on the move but they are also immensely complicated with much more to go wrong than an e-CVT.  There are scores of Volvo owners who have experienced failed Geartronic auto boxes as a result of towing due to overheating caused by the fact that the gearboxes are tiny which means that they struggle to dissipate the heat and the oil coolers are also too small.

The previous owner of this car could have abused the gearbox by constantly changing direction between D and R while the car was still moving or even into P while still moving.

I was just shocked to discover a 400h with a failed gearbox as I have never come across that before.  It just goes to show that even the simplest of gearboxes can still break.

[Gliderpilot]

On 2/1/2019 at 12:53 PM, Rutlandlex said:

Yes I think £3k is somewhat steep for it given that it could potentially cost £2k to fix.  It's impossible to say what the issue might be without seeing it but there are better examples out there with working gearboxes for those who are looking for one of these cars.

I wouldn't go near it. It's a ripoff. Put my 08 plate on WBAC and got a quote of £4k. I think they should give it away.