Good idea to proactively replace RDU

[NV Ray]

2012 P85 #2446 w/130k miles. 2d owner. Bought last Fall from original owner for $27k. Appears to be on original drive unit. All figures in USD.

Since ownership, got BMS_u029 alert 3 days after purchase. Paid $15k for NEW 2022 build replacement pack (got lucky and Tesla honored $15k for reman pack I requested). Paid $1750 plus tax for MCU2 upgrade (that was at my option). Paid $1732 total for PTC replacement with DC-DC convertor fuses.

Thinking of proactively replacing RDU due to reason mentioned in my service request. Looking for experiences, advice, etc.

Am willing to cancel this work if convinced. Thx.

 

[dwbv]

How spaceship does it sound? The LDUs can't be dead silent, right? Isn't there normal electric whine?

 

[NV Ray]

How spaceship does it sound? The LDUs can't be dead silent, right? Isn't there normal electric whine?

Good question. My concern is sound is not present while coasting,only when accelerating. Sound can be heard outside. I'm not hearing similar noise in other Teslas, other than safety spaceship sound at low speeds. But mine is a 2012, don't think they have the safety sound and happens at all speeds.

 

[NewbyMaybe]

If there's an independent EV shop nearby then have the label checked to confirm age. They will probably give you a better warranty also.

 

[Doanster1]

Spaceship sound is normal. Buzzing sound upon acceleration is the dreaded milling noise issue. However, that’s not a death knell, just annoying if irregular sounds bother you. My LDU was replaced under warranty around -50K miles. Shop foreman said it would get louder over time, but not harmful so my choice on whether to replace or wait. I was orig going to drive it until I got closer to the CPO warranty expiration, but just opted to do it since it was fresh in everyone’s minds. No telling if they would’ve replaced it two years later.

 

[ucmndd]

I’d pull the speed sensor and check for coolant intrusion before doing a proactive replacement. If it’s not leaking, I’d keep driving until it is. Given the design flaw present in these motors, proactively replacing one before you really need to just brings the NEXT replacement that much closer.

 

[peeledbanana]

@NV Ray - this video shows how to do that:

 

[SigRed12]

I'm in the same boat about the "spaceship" noise. I too am considering the proactive approach, but I'm concerned it will not eliminate the whine. Has anyone reading this had there P car rear motor replaced and the noise go away? Looking for real world experiences ... not hear-say or educated guesses.

 

[Doanster1]

I'm in the same boat about the "spaceship" noise. I too am considering the proactive approach, but I'm concerned it will not eliminate the whine. Has anyone reading this had there P car rear motor replaced and the noise go away? Looking for real world experiences ... not hear-say or educated guesses.

Three posts up? Again, spaceship/EV whine != milling noise. Buzzing is as close as I can describe it and yes, when they replaced the LDU on my P85D, I got back to normal EV whine.
Not sure why proactive replacement would make sense. Drive it til there’s a real problem or the noise is past your annoyance threshold.

 

[howardc64]

Not sure what spaceship sounds like but jet engine sound is normal on all LDUs and I think most EV electric motors. Most prominent on acceleration and deceleration to a stop (as wind noise dies down) Probably good to find another owner/car nearby and compare.

One note on replacement is will be a reman and quality could be poor. My 3rd and last LDU replacement under warranty was the worst. 2013 original LDU remanned and had a decel whine/hum from day 1. Unfortunately at a time when Tesla HQ clamp down on SC calling for warrenteed LDU replacements (2017-18ish). Everyone at SC just said noises is within spec after that mandate... haha. Anyhow, just noting can also inherit more problems. My #2 LDU was perfect but the tech said they heard something (I'm quite sensitive to new noises and heard nothing) but figured hey a replacement LDU can't be bad thinking its equivalent to 0 mile LDU... how wrong I was... I've done my own rebuild on this LDU and am finding all the QC problems and mistakes Tesla rebuilders made. Anyhow, just as Tesla reman battery pack can be poor quality, LDU is no different. Its a gamble. Might even depend on individual rebuild tech.

 

[howardc64]

Found this write up by Croatia EV repair franchise business outlining the remanufactured LDU they've seen in EU

Letter to Tesla – Large Drive Unit RMN failure – EV Clinic

 

[SigRed12]

Not sure what spaceship sounds like but jet engine sound is normal on all LDUs and I think most EV electric motors. Most prominent on acceleration and deceleration to a stop (as wind noise dies down) Probably good to find another owner/car nearby and compare.

I was loaned a P100D from Tesla while my other car was in the shop. It's my understanding, they both have the same LDU for the rear motor. The P100D did not have the spaceship/milling noise like my P85. The motors aren't different except maybe mine is a reman (1025598-00-H: replaced in 2016; current reman is 1025598-01-U) and the newer one is a production unit (1002633-01-U).

Sounds like the general consensus is to wait until my Rev H grenades then replace it. Sound about right?

 

[howardc64]

I was loaned a P100D from Tesla while my other car was in the shop. It's my understanding, they both have the same LDU for the rear motor. The P100D did not have the spaceship/milling noise like my P85. The motors aren't different except maybe mine is a reman (1025598-00-H: replaced in 2016; current reman is 1025598-01-U) and the newer one is a production unit (1002633-01-U).

Sounds like the general consensus is to wait until my Rev H grenades then replace it. Sound about right?

Alternative is to get it to a good quality LDU rebuilder. I'm only familiar with QC Charge in San Diego.

Tesla LDU reman seems to be random experience. Maybe quality got better already but no one knows until a lot more statistics shows up in the field. Everyone besides Tesla is in the dark and they aren't providing info.

 

[SoCal Buzz]

2012 P85 #2446 w/130k miles. 2d owner. Bought last Fall from original owner for $27k. Appears to be on original drive unit. All figures in USD.

Since ownership, got BMS_u029 alert 3 days after purchase. Paid $15k for NEW 2022 build replacement pack (got lucky and Tesla honored $15k for reman pack I requested). Paid $1750 plus tax for MCU2 upgrade (that was at my option). Paid $1732 total for PTC replacement with DC-DC convertor fuses.

Thinking of proactively replacing RDU due to reason mentioned in my service request. Looking for experiences, advice, etc.

Am willing to cancel this work if convinced. Thx.

View attachment 961736

The milling noise is more of an annoyance and not related to imminent failure. IMO, I would let it ride without replacing another major component until really necessary. Extends the time you will have on warranty when you do eventually replace.

 

[SoCal Buzz]

2012 P85 #2446 w/130k miles. 2d owner. Bought last Fall from original owner for $27k. Appears to be on original drive unit. All figures in USD.

Since ownership, got BMS_u029 alert 3 days after purchase. Paid $15k for NEW 2022 build replacement pack (got lucky and Tesla honored $15k for reman pack I requested). Paid $1750 plus tax for MCU2 upgrade (that was at my option). Paid $1732 total for PTC replacement with DC-DC convertor fuses.

Thinking of proactively replacing RDU due to reason mentioned in my service request. Looking for experiences, advice, etc.

Am willing to cancel this work if convinced. Thx.

View attachment 961736

What's the warranty on your new battery? And what would warranty be on drive unit replacement?

 

[NV Ray]

What's the warranty on your new battery? And what would warranty be on drive unit replacement?

Both out of pocket Tesla remans and new batteries have 4 yr/50k mile. Out of pocket drive unit replacement has same warranty.

 

[howardc64]

For those wanting to proactively exchange their original LDU for a reman. After 2x tear down on my reman, let me share the Tesla reman defects. You'd be wise to stay away from Tesla reman LDU. But for those with failed LDU, not really too many choices. Definitely should check for coolant leak annually and hopefully can get ~6 years (4 year warranty, hopefully a replacement before it ends and last reman LDU lasting ~2 years)

- Leaky seal is the one everyone knows about. In doing the reman myself, I discovered you can't really repolish the seal surface without first perform anti-rust treatment (say chrome plating). I didn't know about anti-rust and my triple lip seal lasted 4k and was full of rust under the trapped chambers between the seal lips. My reman LDU seal shaft had a shallow groove in the middle, presumably that is where the original manufactured shaft's anti-rust treatment had been broken. Without doing proper anti-rust, have to use single lip seal where anti-rust doesn't matter as much. This is probably the reason Tesla went to single lip seal... The reman process couldn't attain originally manufactured shaft rust treatment and finish (~20um surface roughness)

- The highest speed smallest counter bore bearing didn't have retaining compound and spun in its bore. This reman LDU had a loud downhill regen whine since first install. After replacing this bearing with retaining compound. Downhill regen whine was fixed.

- Just discovered one of the inverter mounting bolt holes was stripped and Tesla reman tried to repair it with JB weld or some kind of chemical thread repair. The inverter mounting bolts also need to clamp a coolant passage o-ring. Repair doesn't hold. Hence my original inverter side leak may not have come from leaked seal vaporized and traveled to the inverter. It likely came from improper inverter installation with stripped bolt hole. After opening up my 4k mile rebuild, I discovered new coolant intrusion. Likely from improperly torque around the o-ring with a stripped bolt hole.

Contemplating how to fix this. There isn't much "meat" behind the bolt hole. Just a nub of metal along the coolant channel walls.

So far, my detail inspection of this reman LDU reveals quite the poor worksmanship and even reman method of the coolant shaft and seal is basically improper. No way it can last.

Beyond this, mine was a originally 2013 manufactured reman installed in 2018. No idea how many miles are on it. Surely the large bearings and shafts are original and I'm guessing not much in the way of tolerance checking given the above worksmanship AND reman process defects.

 

[tldickerson]

Howard, have you tried using a helicoil? They work very well in cases like yours.

How To Fix a Stripped Screw Hole in Metal (3 DIY Methods)

We've put together a comprehensive guide to show you how to repair a stripped screw hole on your own using these three proven methods.

www.fixdapp.com

 

[howardc64]

Howard, have you tried using a helicoil? They work very well in cases like yours.

How To Fix a Stripped Screw Hole in Metal (3 DIY Methods)

We've put together a comprehensive guide to show you how to repair a stripped screw hole on your own using these three proven methods.

www.fixdapp.com

Yes familiar with helicoil and varioius other methods but have no experience. Will have someone with experience to assist. My worry is if there is enough material around the hole. Coolant passage is behind the hole and material is in the shape of a mound so not much extra material.

@asavage suggested a couple of sounds things to consider

- 3 bolts rather than 4 maybe good enough to seal. o-ring will get compressed and not much pressure. Coolant residue marks shows clear o-ring pattern likely not leaking when reman LDU was disassembled at 32k miles. Majority of the bolt's job is to bolt this heavy inverter sideways. 15 bolts (3x5 for 3 phases) is what does the holding. Bolts have yellow/tan locktite/glue on them.

- even if drill through to the coolant passage (not preferred of course) it not the end of the world, as long as bolt threads has sealant, it'd be safe.

 

[howardc64]

An update for future efforts assembling the inverter.

15x M6 1.0 16mm bolts holds the inverter. 5 per each of the 3 phases. Only 4.5mm of the bolt enter the threaded hole on the gearbox casing (11.5mm is just going through the inverter hole. Of the 4.5mm, threaded hole is beveled and top 1-2 threads are loose. Therefore, only ~2 threads on each bolt bites in the threaded hole. Therefore, not much margin in this design to tolerate repeated dis/reassemblies

Furthermore, the outer most holes are very close to the inverter phase plates. Most T40 bits are 3/8" and will be tilted by the phase plates. Needless to say, with an angle on the tool and only 2 threads biting. Outer most holes are likely going to strip with more human dis/reassemblies. The outer 2 on each of the 3 phase plates are most likely at risk for stripping. Originally manufactured LDU probably use robotic assembly with fresh threads. But reman units will have a human dis/reassembling these.

When I reinstall these, I use a T40 screw driver (will be tilted) and gently thread the bolt on (yellow locktite 577 for pipes on the bolt tip where the 2 threads bite). Then 3/8 ratchet with T40 bit and very long extension to tighten (not too much. Even 4nm effort will find previously stripped holes)

Can buy M6 1.0 18mm bolts. However, bolt head can't be very big to clear the cast molded side walls surrounding the bolt head. Tried some VW M6 1.0 18mm T40 bolts, head is bigger than Tesla's bolt and may catch the side walls. Smaller 18mm bolts is available but usually with hex heads.

Might be wise if have a reman unit to just helicoil all 15 bolt holes rather than finding out which ones are previously stripped on reassembly.