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Early drive unit milling noise FIX

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Hi everybody, I recently purchased a Rav4 EV with 126,000 miles. This car had terrible drive unit bearing noise, so I took it upon myself to try to fix it.

The Rav4 uses almost exactly the same drive unit as the model S with the large motor, so it has almost exactly the same issues. This was cross posted in the myRav4EV forums, but I thought you might be interested too.

ALL of the noise was caused by bearing failure, however taking it apart exposed a seal failure as well.
Three bearings were in bad shape. The motor bearings had axial play, and the gearbox pinion bearing had fretting on the outer race, indicative of shaft voltage.

Here is a google doc describing it: Rav4 EV drive unit “Milling” noise repair

Please excuse the crudity of the document, I didn't have time to build it to scale, or to paint it.

Lots more pictures here:
https://photos.app.goo.gl/fUffopAvPV64R6kBA

This is my first experience working on an EV, and let me tell you, they are so much easier to work on than gas cars.

Since there are no drive unit service manuals or internal parts available from Toyota, or presumably Tesla, I would encourage others to share as much as you can about replacement pieces and procedures.
 
Wow neat, love this.

Usually bearings in this kind of application have shims of some kind to correctly place them or pre-load them. Did you find any?

Also when FYI when I changed the oil in my 2014 S I discovered Tesla factor fill was right up to the fill plug, much more than the manual which states 1.5 quarts or so. It equals about 1.8-1.9 quarts.
My theory is Tesla discovered putting more oil in makes the drive train more reliable.


Also reading your write up, it's really disappointing Tesla put a goofy liquid cooling rotating tube in there that relies on a rotating seal. Failure dumps coolant into the motor. I'm sure the model 3 doesn't have such a device, I guess that's the price you pay for being an early adopter
 
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I had a hard time getting 1.5 quarts in, but the vehicle wasn’t level when I filled it.

I think the tube thing is pretty clever in that they only needed one seal instead of two. Gas cars have rotating water seals, so I’m not too critical of a single seal.

The motor bearings were preloaded with disc springs, but the transmission was not. The helical gear cut does axially load the transmission bearings, and the race was damaged on the load side.

I’m convinced the damage was from the motor shaft inducing current flow through that bearing, not from lack of preload. The ceramic bearings in that motor would leave only the grounding brush and the transmission for a current path. If the grounding brush was not effective, it just leaves the bearing.
 
I had a hard time getting 1.5 quarts in, but the vehicle wasn’t level when I filled it.

I think the tube thing is pretty clever in that they only needed one seal instead of two. Gas cars have rotating water seals, so I’m not too critical of a single seal.

The motor bearings were preloaded with disc springs, but the transmission was not. The helical gear cut does axially load the transmission bearings, and the race was damaged on the load side.

I’m convinced the damage was from the motor shaft inducing current flow through that bearing, not from lack of preload. The ceramic bearings in that motor would leave only the grounding brush and the transmission for a current path. If the grounding brush was not effective, it just leaves the bearing.

They could have cooled the motor internally with oil then had an oil to coolant thermal transfer with static seals (no sliding or rotation to cause wear). I might be wrong but I think this is what the model 3 rear motor has. The downside is you need some kind of oil pump to force oil through the motor and the heat exchanger; a pump does give you the advantage of being able to put a filter in to catch wear material. The 3 rear motor has such a filter and pump.

You are right gas cars have rotating water seals, but gasser water pumps usually only go 100k miles before they fail and the pump is on the outside, not internal to the motor requiring a motor drop.

The 3 rear motor is a superior design to the S its just the way of evolving designs when you move as fast as tesla does to the market.
 
They could have cooled the motor internally with oil then had an oil to coolant thermal transfer with static seals (no sliding or rotation to cause wear). I might be wrong but I think this is what the model 3 rear motor has. The downside is you need some kind of oil pump to force oil through the motor and the heat exchanger; a pump does give you the advantage of being able to put a filter in to catch wear material. The 3 rear motor has such a filter and pump.

You are right gas cars have rotating water seals, but gasser water pumps usually only go 100k miles before they fail and the pump is on the outside, not internal to the motor requiring a motor drop.

The 3 rear motor is a superior design to the S its just the way of evolving designs when you move as fast as tesla does to the market.


Just because it's later, doesn't necessarily mean it's better. Many times companies over engineer early models and then cut costs as they evolve. It's most likely some things are better and some are a little worse.
 
Just because it's later, doesn't necessarily mean it's better. Many times companies over engineer early models and then cut costs as they evolve. It's most likely some things are better and some are a little worse.

I'm not sure that's true here. This motor has the highest mileage of an single S motor I've seen. The other high mileage S cars that I've seen have had multiple motor swaps.

Tesla has tested the M3 motor to 1 million miles and shown pics of the tested motor internally.
 
I’m not the original owner of this vehicle, but I do have the service history. This drive unit was replaced at ~60,000 miles. So this drive unit had roughly 65,000 miles on it before I tore it down. The gears themselves looked to be in great condition. Even though it was replaced, it was still a rev F unit. I hear things got much better in terms of longevity at rev Q.

I hope my M3 lasts to 1M miles!
 
Hi everybody, I recently purchased a Rav4 EV with 126,000 miles. This car had terrible drive unit bearing noise, so I took it upon myself to try to fix it.

The Rav4 uses almost exactly the same drive unit as the model S with the large motor, so it has almost exactly the same issues. This was cross posted in the myRav4EV forums, but I thought you might be interested too.

ALL of the noise was caused by bearing failure, however taking it apart exposed a seal failure as well.
Three bearings were in bad shape. The motor bearings had axial play, and the gearbox pinion bearing had fretting on the outer race, indicative of shaft voltage.

Here is a google doc describing it: Rav4 EV drive unit “Milling” noise repair

Please excuse the crudity of the document, I didn't have time to build it to scale, or to paint it.

Lots more pictures here:
https://photos.app.goo.gl/fUffopAvPV64R6kBA

This is my first experience working on an EV, and let me tell you, they are so much easier to work on than gas cars.

Since there are no drive unit service manuals or internal parts available from Toyota, or presumably Tesla, I would encourage others to share as much as you can about replacement pieces and procedures.
Great JOB!!! Does this bearing 6007 is ceramic?
 
Great JOB!!! Does this bearing 6007 is ceramic?
I’m not the original owner of this vehicle, but I do have the service history. This drive unit was replaced at ~60,000 miles. So this drive unit had roughly 65,000 miles on it before I tore it down. The gears themselves looked to be in great condition. Even though it was replaced, it was still a rev F unit. I hear things got much better in terms of longevity
I’m not the original owner of this vehicle, but I do have the service history. This drive unit was replaced at ~60,000 miles. So this drive unit had roughly 65,000 miles on it before I tore it down. The gears themselves looked to be in great condition. Even though it was replaced, it was still a rev F unit. I hear things got much better in terms of longevity at rev Q.

I hope my M3 lasts to 1M miles!

Awesome description. How is your repair holding up? Especially with the seal on the rotor cooling system. Thanks!
 
Will the listed replacement bearing cause another electrical arc issue or is it ceramic? Would the same bearing work on a 2016 tesla motor? I bought a used 2016 and wanted to do a similar “overhaul” having a ton of trouble finding the bearings, thanks!
 
Will the listed replacement bearing cause another electrical arc issue or is it ceramic? Would the same bearing work on a 2016 tesla motor? I bought a used 2016 and wanted to do a similar “overhaul” having a ton of trouble finding the bearings, thanks!
I am fully expecting the replacement bearing to fail in the same way as the original. I would not recommend a ceramic bearing in that location without installing some means of grounding the rotor. The next electrical path is the gears themselves. I'd rather replace bearings than gears.
 
Schenkzoola how has your RAV 4 repair held up? Also, do you happen to know if the RAV4 DU you repaired would be a found in a P or Standard Model S? Any idea if the motor rotors are the same in the Std vs P DU? Trying to determine what the replacement SKF bearing would be for a 2013 P85 would be. Any more info on source of bearings and seals since your original post? The first Model S's have warranties expiring which is going to be very interesting top watch as far as the Out of Warranty S models is concerned. That was a great DIY by the way. I work on a lot of ICEs and based on what I saw in your write up, these Tesla DU's appear to be many times easier to tear down and repair than an ICE. Looks like the biggest obstacle is finding the proper parts but maybe with warranties expiring this will change. After all nature abhors a vacuum!
 
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Hi everybody, I recently purchased a Rav4 EV with 126,000 miles. This car had terrible drive unit bearing noise, so I took it upon myself to try to fix it.

The Rav4 uses almost exactly the same drive unit as the model S with the large motor, so it has almost exactly the same issues. This was cross posted in the myRav4EV forums, but I thought you might be interested too.

ALL of the noise was caused by bearing failure, however taking it apart exposed a seal failure as well.
Three bearings were in bad shape. The motor bearings had axial play, and the gearbox pinion bearing had fretting on the outer race, indicative of shaft voltage.

Here is a google doc describing it: Rav4 EV drive unit “Milling” noise repair

Please excuse the crudity of the document, I didn't have time to build it to scale, or to paint it.

Lots more pictures here:
Rav4 EV Drive Unit

This is my first experience working on an EV, and let me tell you, they are so much easier to work on than gas cars.

Since there are no drive unit service manuals or internal parts available from Toyota, or presumably Tesla, I would encourage others to share as much as you can about replacement pieces and procedures.
This is great. What are the dimensions of the seal itself? when combining the seal with spacer, what would be the combined dimension? 30X55x8?
 
This thread is awesome, thank you for sharing! It's been a couple years now, how is the repair holding up? How many miles have you done on it?

Also, kinda the question in the back of my mind. This looks pretty identical (other than the parking pawl you mentioned) to the standard large Tesla rear drive unit. Any idea whether it's the same actual motor, limited in HP by either software/controller or battery size?
 
Hi everybody, I recently purchased a Rav4 EV with 126,000 miles. This car had terrible drive unit bearing noise, so I took it upon myself to try to fix it.

The Rav4 uses almost exactly the same drive unit as the model S with the large motor, so it has almost exactly the same issues. This was cross posted in the myRav4EV forums, but I thought you might be interested too.

ALL of the noise was caused by bearing failure, however taking it apart exposed a seal failure as well.
Three bearings were in bad shape. The motor bearings had axial play, and the gearbox pinion bearing had fretting on the outer race, indicative of shaft voltage.

Here is a google doc describing it: Rav4 EV drive unit “Milling” noise repair

Please excuse the crudity of the document, I didn't have time to build it to scale, or to paint it.

Lots more pictures here:
Rav4 EV Drive Unit

This is my first experience working on an EV, and let me tell you, they are so much easier to work on than gas cars.

Since there are no drive unit service manuals or internal parts available from Toyota, or presumably Tesla, I would encourage others to share as much as you can about replacement pieces and procedures.
Do you have an update on the status of your repair? Thanks for posting. I have an Extended warranty but Toyota are dragging their heels executing the warranty and long term I'm contemplating tooling up so I can do my own repairs. That means getting a motor cradle and jack plus all the other tools to be able to drop the battery. It's been a while since I rebuilt engines but EV motors are a lot simpler!
 
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Reactions: vanR
Revisiting this old thread, but I just recently picked up a 2013 RAV4 EV that has this issue. We're having issues disassembling the motor to do the repair and I have a few questions:

Q. Does the rotor and stator area need to be separated to clean up?

Q. If so, does the rotor simply slip out of the drive gear on the gearbox side, or must there be disassembly from the gearbox side in order to remove the rotor?

Q. Does the induction area simply need to be cleaned only, or can we anticipate electronics damage as a result of the presence of coolant?

Q. Any recommendations on where to source the parts for the repair?