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Out of Warranty Drive Unit Replacement and Cost

ajbessinger

EV Repair Technician at QC Charge
Sep 2, 2020
55
157
San Marcos California, USA
How the heck do you have so many miles on a 6 year old car?
It's actually only a little over 5 1/5 years old ;). The previous owner used it full time for Uber, and I purchased it from him about 7mo ago. When I bought the car, on September 1st last year, it was almost exactly 5 years old (August build date) and had 408k miles on it, which works out to an average of over 80k mi/year!
Are you still on the original battery pack
According to the previous owner, the battery pack has been replaced once under warranty, at about 250k mi. The current pack is now at somewhere around 170k mi, and has ~87% capacity. Considering the way the car was used before (likely driven over 300mi/day 5 days a week, and also supercharged on an almost daily basis), I'd say it's doing pretty good!
 
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powaking

Member
Feb 1, 2018
434
264
Massachusetts
Definitely, in fact I'd say they are near bulletproof. The small rear drive unit in my 2015 S 70D is still original at 418k+ mi, and the front one has only been replaced once (at about 375k mi).
Phew. That's definitely good to hear. We do have Electrified Garage up here in New England but we should could use a few more shops like yours. Hopefully more will start to pop up.
 

2101Guy

Active Member
Jan 6, 2020
1,709
1,653
USA
DC area has a huge market gap if they dont have at least one really good shop that has the proven capability to do drive unit rebuilds. LOTs of Teslas in the DMV area
 

dark cloud

Active Member
Apr 14, 2018
2,020
2,272
BC
We offer a 1 year warranty on all of our work.
But they should be good for a million miles? :cool:

edit: Actually, regarding the drive units in that +400 K mile car, has the fluid been changed? Or do you know what condition it is in? And what is your shops philosophy regarding the Dextron VI change interval?
 

TonyT

Member
Nov 5, 2018
839
683
Orange county, CA
Good to see indy garages like QC Charge picking up the ball for this very underserved sector. One of the biggest worries buyers of older Teslas have is drive units out of warranty. If anyone on this thread has a list of other garages I can refer as well, this would be greatly appreciated. Cheers, Brent @ XCare.
Is X-care allowing non tesla certified repairs now?
 

ajbessinger

EV Repair Technician at QC Charge
Sep 2, 2020
55
157
San Marcos California, USA
But they should be good for a million miles? :cool:

edit: Actually, regarding the drive units in that +400 K mile car, has the fluid been changed? Or do you know what condition it is in? And what is your shops philosophy regarding the Dextron VI change interval?
The front drive unit has been swapped out once, so that one would have had new fluid in it at the time it was put in ~40-50k ago. As far as the rear drive unit, I'm not sure... But I know it had new axles installed at the same time that the front drive unit was swapped. I should probably pull my car in one of these days to check the levels. I have done a fluid change on another dual motor S, and it is not particularly easy to get to the fill plugs.

I would say that to change the gearbox fluid every 100k probably wouldn't be a bad idea, as the gears do wear and cause a slight buildup of metal particulates (though there is a magnet inside the gearbox that picks most of that up). ATF also has a lot of additives that can break down over time, so age can play a factor too. If you ever want to do a fluid change, IIRC, the front drive unit takes ~2.5qts of fluid, and the rear takes ~1.5qts.
 

ajbessinger

EV Repair Technician at QC Charge
Sep 2, 2020
55
157
San Marcos California, USA
Other than the case being damaged what other parts would cause the drive unit to be unserviceable?
There are a few things that could lead to it being unserviceable.

One would be coolant intrusion, usually this doesn't cause problems with the motor being un-rebuildable (even if the motor is seized from corrosion we can usually fix it), but if the coolant gets to the inverter than can pretty much destroy it. Unfortunately it's exceptionally rare to find a replacement inverter that is separated from the rest of the drive unit, so the only solution is to get a whole drive unit.

The second is the rotor/primary drive gear splines. On older drive units especially, the grease can get cooked out of the splines, which then leads them to getting worn out, sometimes to the point where they strip out entirely. This is actually our most common reason for drive units being junked. We probably have 8-10 drive units sitting on shelves for this exact problem. Currently we have no fix for this, though we have a few ideas to try and re-spline the shaft and gear...

Then there are few random oddball issues that are flukes and one-offs. I've seen drive units and/or inverters damaged by manufacturing defects, like blocked cooling passages, and weird gear-train noise problems. I've even pulled a drive unit from a car that was swapped in, and never had the gearbox filled with oil (the owner bought the car used, and never knew the drive unit had been swapped, drove it that way for 20k+ miles and it sounded HORRIFIC when they brought it in to us).
 
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demundus

Active Member
Jul 5, 2015
1,324
856
Oceanside, CA
There are a few things that could lead to it being unserviceable.

One would be coolant intrusion, usually this doesn't cause problems with the motor being un-rebuildable (even if the motor is seized from corrosion we can usually fix it), but if the coolant gets to the inverter than can pretty much destroy it. Unfortunately it's exceptionally rare to find a replacement inverter that is separated from the rest of the drive unit, so the only solution is to get a whole drive unit.

The second is the rotor/primary drive gear splines. On older drive units especially, the grease can get cooked out of the splines, which then leads them to getting worn out, sometimes to the point where they strip out entirely. This is actually our most common reason for drive units being junked. We probably have 8-10 drive units sitting on shelves for this exact problem. Currently we have no fix for this, though we have a few ideas to try and re-spline the shaft and gear...

Then there are few random oddball issues that are flukes and one-offs. I've seen drive units and/or inverters damaged by manufacturing defects, like blocked cooling passages, and weird gear-train noise problems. I've even pulled a drive unit from a car that was swapped in, and never had the gearbox filled with oil (the owner bought the car used, and never knew the drive unit had been swapped, drove it that way for 20k+ miles and it sounded HORRIFIC when they brought it in to us).
How did you get the halfshafts off? The manual specifies a tool, I was too afraid to muscle them out for fear of breaking something. Is it just brute force and some makeshift prytool?
 

Jsvette56

Member
Feb 25, 2013
89
58
Santa Clara
GO to small claims court. I've been to small claims court twice and have found the defendant typically settles before the case is heard. The filing fee is probably less than $100.

I had my 2013 MS drive unit willingly replaced by the SC twice due to noisy bearing.
 
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ajbessinger

EV Repair Technician at QC Charge
Sep 2, 2020
55
157
San Marcos California, USA
How did you get the halfshafts off? The manual specifies a tool, I was too afraid to muscle them out for fear of breaking something. Is it just brute force and some makeshift prytool?
A regular pry bar works just fine, just make sure to be careful in what you pry against.

It usually takes a sudden jolt to get it to pop loose from the gearbox, so get the prybar situated where you want it, then give it a sudden jerk. Sometimes they can be pretty stuck in there and it may take a few tries, and others they will pop loose pretty easy.
 
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ronrattie

New Member
May 30, 2021
1
0
Frederick, MD
At our shop, the most common reason for drive unit rebuilds these days is actually due to the coolant seals failing, and not nearly so much milling noise (in later motors, they switched over to ceramic bearings which mostly fixes the milling issue, but they also changed the coolant seal to an inferior design that does not last). A full rebuild is $4,000, assuming the drive unit is in "functional" condition and can be rebuilt.

If we were to do a full overhaul at the shop where I work, we would:
-Replace rotor bearings with upgraded hybrid ceramic bearings
-Replace primary drive gear bearings
-Replace rotor coolant seal with an upgraded triple lip PTFE seal
-Inspect all parts of the drive unit for excess wear (splines, gears, etc.)



I assume it's the same $4000 for the replacement of the bearings on the Tesla motor in a Mercedes B-class Electric Drive?
 

Snowballmo

Member
Apr 22, 2021
5
7
Santa Clara CA
1.) The DU isnt actually the issue its the halfshafts and bearings. you could take it to someone who could swap it for you. there is a guy in el cajon, ca who dismantles teslas and does some work on the side. They are a member here. I don't want to shill for him or put him in an awkward spot, but google a little bit and find them, reach out and see if they'd be willing to swap your half shafts if you buy from them

OR

2.) Go to small claims court against tesla for the 10k (full amount in small claims) for willfully disregarding your concern while under warranty, and then reversing course and agreeing with you after warranty. They would have to fly a company rep to LA (lawyers cannot appear on their behalf), and either wouldn't show (default to you) or a C level/VP would have to show up and explain why they did what they did.

Then... OR

3.) Pay them to fix it

I have a similar problem to OP on my 2013 Model S85 built 3/13 so it's just a few months out of warranty. There were no signs of this issue before hand (no grinding noises). I heard a loud "thunk" and then no more power was available to the wheels, just a "whirring" sound. No other problems, just no power to wheels. Had to have it towed to SC. They immediately said it needs a new DU, no other details or explanation. This seems like an expensive approach if the DU could be rebuilt.... I asked if this was covered by warranty or what it will costs but have not heard a response yet. I suspect they will quote me a high number like OP... I will post more details when I get them. Any advice would be greatly appreciated!
 

Asummers

Member
Feb 3, 2018
7
3
Dayton oh
As far as I know my DU is doing fine. But if I did the sensor check for coolant, and found contaminants, would this be evidence enough to get Tesla to replace the DU under warranty? I still have 19 months of warranty remaining. 60K miles on original DU. Thanks
 
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polyphonic54

Member
Aug 29, 2019
329
254
USA
Wow. I wasn't expecting such a high cost. Tesla needs to start getting creative with how they are servicing the drivetrain/battery components otherwise all of their cars are going to end up worthless after 8 years.
Just stumbled across this thread. These prices are infuraiting. It really eats into the environmental argument for owning a Tesla.
$11k for a drive unit (which some cars have two)
$2.5k for a display screen and computer
$22k for a battery

I remember when we bought our Model 3 it was projected to be "$5-7k" for a new battery (then clarified to modules). Right to repair cannot come soon enough..
 
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Snowballmo

Member
Apr 22, 2021
5
7
Santa Clara CA
I have a similar problem to OP on my 2013 Model S85 built 3/13 so it's just a few months out of warranty. There were no signs of this issue before hand (no grinding noises). I heard a loud "thunk" and then no more power was available to the wheels, just a "whirring" sound. No other problems, just no power to wheels. Had to have it towed to SC. They immediately said it needs a new DU, no other details or explanation. This seems like an expensive approach if the DU could be rebuilt.... I asked if this was covered by warranty or what it will costs but have not heard a response yet. I suspect they will quote me a high number like OP... I will post more details when I get them. Any advice would be greatly appreciated!
SC called me today and told me it's covered under warranty but will take 1-2 weeks longer to replace. :oops:🥳🙌
 

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