Milling noise FIX

[Johan]

Discussion about this topic can become very long and spread over multiple threads, forums, youtube, etc, making it difficult to find the info you need. @howardc64 (TMC user) and I created an info directory (a website) dedicated to this LDU, especially the coolant leak problem. It contains links to rebuilds by multiple individuals and also a list of past and current seal longevity experiences, torque specs, etc.

Dirctory link: https://sites.google.com/view/teslaldu

 

[ph2]

Few pictures from my rebuild... bearings were in bad shape, Aegis ring can be seen (doesn't do so well with rotor shaft current grounding as was apparent when checking out the pinion bearings.) Decent amount of ATF throughout; not much coolant but did find droplets on speed sensor. One note I could not find anywhere else, the bearing preload springs on the ODE bearing oppose each other... 2 with their outer circumference contacting outer bearing race and 2 with their outer circumference contacting the circlip in the housing creating a V-shape. I did open up the new bearings and replaced their grease with Polyurea EM grease as SKF recommends this more than the calcium or lithium grease bearings normally ship with from the factory.

 

[lemketron]

Few pictures from my rebuild... bearings were in bad shape, Aegis ring can be seen (doesn't do so well with rotor shaft current grounding as was apparent when checking out the pinion bearings.) Decent amount of ATF throughout; not much coolant but did find droplets on speed sensor. One note I could not find anywhere else, the bearing preload springs on the ODE bearing oppose each other... 2 with their outer circumference contacting outer bearing race and 2 with their outer circumference contacting the circlip in the housing creating a V-shape. I did open up the new bearings and replaced their grease with Polyurea EM grease as SKF recommends this more than the calcium or lithium grease bearings normally ship with from the factory.

View attachment 53

I found it so interesting that there is a date/time written on the inside of this part -- is there a story behind that?

Here's mine from a August 2014 RAV4-EV (marked 5/29, 9:22pm):

 

[n3ckf]

I found it so interesting that there is a date/time written on the inside of this part -- is there a story behind that?

Here's mine from a August 2014 RAV4-EV (marked 5/29, 9:22pm):
View attachment 80

When Tony rebuilt my motor (about 5000 miles ago, this was the 2nd one, my original was replaced at 25K miles) he used ceramic bearings to replace the original steel ones. Allegedly this prevents the arcing that occurs with the steel ones which degrades them (had been degraded considerably on my motor which had 60K on it at the time).

 

[ph2]

I found it so interesting that there is a date/time written on the inside of this part -- is there a story behind that?

Here's mine from a August 2014 RAV4-EV (marked 5/29, 9:22pm):
View attachment 80

I can only guess that is the date the seal was installed; the date pictured in mine matches the date of manufacture for the drive unit… which makes me wonder if the seal was thought to be an issue worth tracking that early. Otherwise it could just be used as a reference in the manufacturing process.

 

[ph2]

When Tony rebuilt my motor (about 5000 miles ago, this was the 2nd one, my original was replaced at 25K miles) he used ceramic bearings to replace the original steel ones. Allegedly this prevents the arcing that occurs with the steel ones which degrades them (had been degraded considerably on my motor which had 60K on it at the time).

Do you know if he limited the use of ceramics to the motor or also replaced the pinion bearings with ceramics?

 

[lemketron]

Related question: Did later RAV4-EV motors (2014-ish) ship with ceramic bearings or were all of them the same? I never had any milling sound (with 42K-ish miles), nor any indication (when doing the coolant delete) of bearing grit/debris in the motor. I'm hoping that (combined with having coolant delete now) might be a good sign regarding the future of this motor in my car.

 

[asavage]

Early production LDUs had an Aegis ring (whisker brush) that was supposed to ground induced rotor current; this didn't work as well as engineered, and the rotor brgs took a lot of abuse, deteriorated much more quickly than designed, and caused a lot of failures and noisy units.

Later units discarded installation of the Aegis ring and substituted ceramic balls in the ball bearings of the rotor bearings; by Tesla "Rev Q" (2016) this was universal. It's not known when the ceramic ball bearings were phased in before then. It's also not known when the reman units supplied for RAV4 EVs got them from Tesla. All the non-Tesla LDU rebuilders use them, esp. as you can't buy the Aegis rings from Tesla nor anyone else; they appear to be bespoke.

I assume that no RAV4 EVs were shipped with ceramic ball bearings on the rotor. My '14 had a noisy LDU when I bought it @ 49k and I ran it another year until 59k (just before the factory warranty ended) and had it replaced under warranty for noise; Toyota gave me no hassle when I asked for a replacement. They evaluated the noise (took it for a drive) and ordered a reman LDU from Tesla. It took five weeks total.

Installation of ceramic bearings moves the rotor grounding issue downstream to the rotor-to-pinion-gear splines, the pinion bearings, and the pinion gear. These seem to hold up much better than the steel rotor bearings did, but rebuilders have noted pitting of the pinion gear during rebuilding, and deteriorated splines remains and issue. Best practice seems to be to replace at least the nearside pinion bearing & its seal when replacing the rotor bearings.

Pictures of the Aegis ring are earlier in this thread.

 

[lemketron]

So it sounds like the later RAV4-EVs might at least be missing the Aegis ring (whisker brush) even if they never got ceramic bearings. Is there any aggregated data on which years (or VINs) had motor replacements (and at what mileage)? I have six months left on my 10yr extended warranty (PSA) but have never had any milling sound which I'm told is required to qualify for a motor replacement (under warranty). It's not clear if that will happen in the next six months, and from what I'm reading it's not clear that I'd want to push for one without knowing if a reman motor would be better (e.g. ceramic bearings) than my current one (as it seems that Tesla's reman process doesn't necessarily resolve previous damage to the rotor...). And now that I have the "coolant delete" installed, I'd need to remove that if I didn't want to lose it (nor have to explain it).

 

[davewill]

If I had a motor that didn't make the milling noise and didn't have coolant behind the speed sensor, I wouldn't want a reman replacement. Many (most?) of the RAV4EV (and early Model S) motors just seemed to work without problems. Those of us who did have the milling noise and got replacements often found that the replacement motor would then develop the problem. I had two motor replacements before I got one that didn't start making noise, although it did show water behind the speed sensor before I decided it was time to trade it in.