Tesla repair expenses on older Model S / X -- PART 2: Drive unit/drivetrain, failures, replacements

Drive unit / drivetrain failures on older Model S / X can be very disruptive and expensive -- especially if you're out of warranty -- and there are new options in available for owners of vehicles using Tesla's "large rear drive unit" that *should* make the next drive unit you buy your last drive unit. We'll discuss why they break, what the design issues are with new and refurbished units and how you can make sure you get "The Good One."

Rear lower control arm replacement -- getting access to the speed sensor:

Follow-up conversation in 3 parts:
1-- Battery concerns

2-- Drive unit concerns

3-- Sweet Spot to upgrade

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[markschultz]

I had my drive unit replaced under warranty in November of 2021, they did not install the Updated drive unit as it "wasn't available at the time". Now i'm worried my drive unit is a ticking time bomb.

[steveschulzelectronicswiz]

The delete entails sealing off the Rotor cooling path within the manifold. The flyover tube you are showing is on all motors new and old and stays on the coolant delete part too since it moves coolant from the manifold to the top of the gearbox as in the original.

[peteroffpist]

Agree thanks I have come to the same conclusion .

[slartybartfarst]

I own a P85 bought new 2014 now 145, 000 miles, as an ex engineer 44 years world wide in big auto. You are WRONG. Version "U" does not define the "tube" that is on all motors. The tube takes coolant to the gearbox, specifically the output bearings.
The "U" drive units will be fitted with hybrid armature bearings using ceramic ball bearings that do not provide a path to ground for induced electrical currents that would otherwise galvanicly destroy the bearing along with other more minor enhancements.
The coolant delete removes the need for the seal on the feed end of the armature shaft, this seal always seemed to me to have a failure mode that far outweighed the benefit, but Im viewing it from my use case.
I live it the UK, it is not often that hot and there is rare opportunity to run the car at any where near the full load for any extended time therefore generating a large heat burden.
To delete the coolant seal I will jack the car, remove the LH rear wheel and undo the aluminium gallery / top cross feed pipe nut. Once undone it is only possible to move the galley away from the motor rather than remove it as it hits the sub frame with the coolant feed tube still in the armature.
Slice the feed tube off the gallery and remove the gallery for modification. Slice up the remaining feed tube incrementally as you remove it section by section.
Machine the galley to accept a stainless steel turned plug and refit.
When to do all this? Im a machinist and I have the machines and I wont do it unless its needed.
Ive already inspected the encoder sensor, it was dry so I have a good drive unit.
Theres nothing new here, weekly inspect your tyres and coolant level, save a fortune.
Ive drilled a 3 inch hole in the plastic panel above the coolant header tank I can see the coolant level, if it starts dropping its going somewhere? Theres your answer do the mod now or do it before if you have the time / inclination, either way dont leave it till its too late, prevention batter than cure ££££

[aussietaipan]

This is incorrect about the information on the tube that goes from the manifold to the gear housing, my 2015 model S has the original problem rear motor and it too has the same tube. The actual difference is the water tube that goes from the manifold into the stator on the old design, this is deleted on the U design so coolant now does not enter the stator section where the seal fails and coolant enters the motor, gear box and inverter. I have already modified my model S with the coolant delete and it runs well.

[PKerusso]

I have a 2019 P100D. It’s making the windmilling noise. What causes that ?

[berchang]

My one year old 2014 model A 85 just took a shit. With only 60k miles. My question is, is it worth it to fix it. Tesla wants 9k. Also upside down on car loan.

[jackgreenstalk]

So does the non performance motor have more reliability? I HAVE a 2014 model a 60 and it seems to be running great at 130k miles.

[msimonse]

I could read any of your screen shots or part numbers.

[robertcampbell]

EVs throw away vehicles and that's saving the planet Apparently but i fail to understand how