DIY Electric Car Forums banner

1 - 12 of 12 Posts

·
Registered
Joined
·
232 Posts
Discussion Starter · #1 ·
Does anyone know if the Tesla large RWD drive unit gearbox has an actual oil pump, or does it use the main gear to sling the oil around inside?

I've tried searching, but either it's just too specific of an item or it hasn't been described anywhere I can find...
 

·
Registered
Joined
·
1,498 Posts
i quit keeping track on the TMC drivetrain failure thread several years ago after they were up to revisions Q, R or S. They had a rash of gearbox issues and didn't have a pump at that time.

i had this drawing of the jenner in my files, but don't remember the history. It appears to use a slinger tube with gravity feed for the bearings.
 

Attachments

·
Registered
Joined
·
232 Posts
Discussion Starter · #3 ·
Thank you. The lubrication setup (only my opinion) looks almost like an afterthought. Just trying to understand if it would be possible to run the drive unit in reverse orientation, but it doesn't look possible. It would need some custom external pump setup...
 

·
Registered
Joined
·
1,498 Posts
i would think that the "pumping" action for the slinger tube works in either direction.

i don't think you could mount it upside-down due to the gravity feed-holes on the bearing bosses, but the cars have to run in reverse and the lube system still has to supply oil.

if you buy one and take it apart, please post up some good detailed pictures.

My first theory on the failures was excessive axial load on the radial-contact bearings due to the thrust from the helical-cut gears. Another was possible fretting due to AC current thru the motor bearings. i don't know if a cause was ever determined or revealed, or a permanent fix found.
 

Attachments

·
Registered
Joined
·
232 Posts
Discussion Starter · #5 ·
That last picture is of the Roadster gearbox, which is a different design.

After some looking around at various tear downs and photos online... The model S gearbox oil pump is geared to the main gear, picks up oil from the bottom of the gallery, then pumps to 3 outlets, 2 that squirt onto the bearings on the shaft coming from the motor, and another outlet that goes into the back of the housing to (presumably) oil the secondary shaft bearing. It's not clear that oil picked up by the main gear would be properly distributed around to all the bearings if it constantly rotated backwards.

Most other gearboxes have oil passages built in the case, with external access plugs that could be used, but not the model S...

Thanks for your help.
 

·
Registered
Joined
·
1 Posts
The little that I've heard about the Tesla Drivetrain is that the gears are only oiled in the forward direction.
Therefore, it is not recommended to drive the Tesla Model S in reverse at more than 15 mph.

My sources on this information are:
EVTV.me
Check out their videos on the subject.
170303 Tesla Drivetrain Update
170721 Tesla Drive Unit Quaife Differential Install
170331 Tesla Motor Coolant Flow

EVBMW.com
Damien ran a test bench Tesla motor in reverse at high speed (10,000 RPM?).
He ran it with no load, so it's unlikely any damage was done.
However, Jack Rickard of EVTV did remark in the comments that the TMS drivetrain should not be run in reverse at high speed.

Rich Rebuilds may be another source for information on this topic, as he has rebuilt a number of Teslas from salvaged components.

I do not have any information on whether modifications to the Tesla drivetrain have included a bidirectional oil pump.

Please comment if you have any information to the contrary.
Thank you
Rick
 

·
Registered
Joined
·
1,498 Posts
If either of you have, or have found, pictures or diagram of the oil pump, please post them up--would be interested to see the details.
 

·
Registered
Joined
·
1,498 Posts

Attachments

·
Registered
Joined
·
2 Posts
A note on this topic: The Toyota RAV4 EV (2012-2014) uses a Model S LRU (with addition of an electrically-operated Park lock, so the casting is likely different from the Model S).

Unlike the Model S LRU, where the motor & inverter are aft of the axles, on the RAV4 EV the motor & inverter are forward of the axles.

I wonder about the lubrication on these, as these run "backwards" to go forward.

121619


121620


121621
 

·
Registered
Joined
·
1 Posts
The Rav4 and Tesla units are very similar - its a bad pictured example here. The intermediate gear and the diff are identical.
The primary gear is the same, only it has a different collet on the top.

I have just stripped and rebuilt my gen1 model S drive unit and inverter.

It does have an oil pump, which sucks as it move in forward direction and then squirts directly at the primary gear.

Some pics attached - if anyone wants any more specific pictures let me know - its still in bits for another few weeks.

121968
121969
121967
121970
 
1 - 12 of 12 Posts
Top