MODEL S GEARBOX OIL

[Electriccarnut]

I am the happy owner of a 2013 Model S85 ex-salvage vehicle. Since Tesla is hinky about doing maintenance on my car I plan to do much of it myself. Currently I want to change the gearbox oil. The service manual (or at least the one I have) says that two different oils were used, Mobil SH 629 and Dexron 6 and that the 629 was used in the early front drive units only. Does anyone know for sure if the early rear drive units (large motor) used Dexron?

 

[Kiwiadventure]

I am the happy owner of a 2013 Model S85 ex-salvage vehicle. Since Tesla is hinky about doing maintenance on my car I plan to do much of it myself. Currently I want to change the gearbox oil. The service manual (or at least the one I have) says that two different oils were used, Mobil SH 629 and Dexron 6 and that the 629 was used in the early front drive units only. Does anyone know for sure if the early rear drive units (large motor) used Dexron?

Tesla will know all about your car

 

[Electriccarnut]

Uhhhh….. Oh yes, they do. They don't want anything to do with salvage vehicles even though mine has gone through rebuild title and currently has a clean California title. They wouldn't even sell me a license plate mount.

 

[sledom]

Uhhhh….. Oh yes, they do. They don't want anything to do with salvage vehicles even though mine has gone through rebuild title and currently has a clean California title. They wouldn't even sell me a license plate mount.

Same boat here, I’m pretty sure they will sell you parts and give you information, at least my service center will here in WA. Sorry I can’t help with the gear oil. But I do know that Tesla service will perform all maintaince on my, still “rebuilt” title, they require a HV inspection for 500$ to do any work on the electrical. Seeing as the gear box doesn’t have any electrical components they should work on it or at least help you out.

 

[ElectricTravel]

Currently I want to change the gearbox oil. The service manual (or at least the one I have) says that two different oils were used, Mobil SH 629 and Dexron 6 and that the 629 was used in the early front drive units only. Does anyone know for sure if the early rear drive units (large motor) used Dexron?

Through at least 2017, the large rear drive unit fluid is Dexron 6. Capacity is 1.5 quarts/1.4 liters.

Large rear drive units were on all rear wheel drive Model S and Performance Dual Motor Model S.

While we're on the subject, here's a really important note for Dual Motor cars: The fill hole on the small drive units (front and rear) is not in the correct location; if you refill to that level you WILL overfill it. This is a truly moronic design flaw, as it is different from literally every other car on the road. Once you've drained the fluid, refill only the quantity shown in the Service Manual. In a pinch, measure how much came out and refill with that same amount.

 

[a1syd]

So, I have just stripped and rebuilt my early large drive unit. 1002633-00-f and I can tell you that it did not have Dexron VI in it, it was a more dark oil like fluid so I reckon it was indeed mobil SHC 629.
I cannot really understand why they changed to Dexron 6 on the newer motor as the bearing and gears are all similar. It must be to do with the alternative seals used perhaps.
I cannot source SHC 629 here in the UK for smaller than 20L at a time, So I am either going to use Synthetic gear oil 75W-90 or Dexron 6.
There is nothing special in the gearbox at all when you compare it to ICE cars automatic gearboxes which are far more complex beasts. its simply 3 cogs and a diff with a couple of open bearings and a mechanical pump. So i don't believe it will be very fussy at all.
The SHC 629 just gave a very long service life on paper.

 

[soarhead25]

Through at least 2017, the large rear drive unit fluid is Dexron 6. Capacity is 1.5 quarts/1.4 liters.

Large rear drive units were on all rear wheel drive Model S and Performance Dual Motor Model S.

While we're on the subject, here's a really important note for Dual Motor cars: The fill hole on the small drive units (front and rear) is not in the correct location; if you refill to that level you WILL overfill it. This is a truly moronic design flaw, as it is different from literally every other car on the road. Once you've drained the fluid, refill only the quantity shown in the Service Manual. In a pinch, measure how much came out and refill with that same amount.

On my 2016 MS90D, the fill plug is way too high on the front diff to be a fill-level indicator, and yes- you will definitely over-fill the diff, so I agree with you there. But on the rear diff, there is a specific service procedure to fill thru the output shaft hole once the cv axle has been removed. This axle shaft hole is a bit higher in elevation than the fill plug which they say not to use as a fill hole. My theory is that the diff requires a slight overfill condition that you can't achieve with the fill plug in its location and pitch angle of the diff unit. The P service procedure does not call this out and the fill-plug can be used as normal.

 

[soarhead25]

So I am either going to use Synthetic gear oil 75W-90 or Dexron 6.

What fluid did you wind up using? Having a hard time sourcing the SHC 629 and not in a 5 gal pail.

 

[soarhead25]

On my 2016 MS90D, the fill plug is way too high on the front diff to be a fill-level indicator, and yes- you will definitely over-fill the diff, so I agree with you there. But on the rear diff, there is a specific service procedure to fill thru the output shaft hole once the cv axle has been removed. This axle shaft hole is a bit higher in elevation than the fill plug which they say not to use as a fill hole. My theory is that the diff requires a slight overfill condition that you can't achieve with the fill plug in its location and pitch angle of the diff unit. The P service procedure does not call this out and the fill-plug can be used as normal.

Thought I would add this picture I managed to take yesterday as a follow-up.

 

[L-P-G]

Anyone have a picture of the fill/drain plug on the front drive unit? I'm preparing to do this service and the service manual does not show where they are.