DIY Tesla Drive Unit Repair

[Gtech]

Grease on Speed Sensor

Thats packed with some serious grease. Its pretty obvious Tesla original/reman LDU rotor shaft+seal are packed with grease for some reason (maybe to help install?) I've been thinking triple lip packed with grease might last longer (original early LDU that didn't get swapped out due to early clunk and bearing noises seems to last the longest : 7-8+ years and some even over 150k miles)

Yours is a Reman (R1), all the remans I've seen had single black lip PTFE seal. Was yours single lip also?

Yes single lip

Moisture In Inverter

B+ B- cables has an o-ring that sits on the bottom of the tunnel to prevent moisture ingress. But poor orientation as condensation will just sit and receive gravity assist. Perhaps the moisture inside B+ B- cover just came from ingress through the o-ring?

Yeah we greased them but think it's wise to pull the B+ B- cover again after like 6 months or so to check for moisture or replace the O rings anyway. After I think about it one cable had almost no resistance when pulling it out of the LDU, the one with less corrosion was a little bit harder to remove but also almost no resistance. You can even see that the left O ring has lost it's stretch:

Does the car live in a high moisture environment in Netherland?

80-85% on average

Sticky Slime

My 2017 reman LDU inverter casing was perfect clean outside (had coolant terrarium on inside due to seal leak towards connector end due to slightest grade tilted down on passenger side)

There are 2 sources of "slime" inside the LDU : One is the jelly covering all the IGBTs on the 3x phase boards. The other is inside the CANBUS connector plexiglass housing encasing the interface board. If you squeeze that housing, jelly will move around. Presumably these are to prevent moisture condensation from settling on top of key electronics such as IGBTs and CANBUS interface.

I wonder if your CANBUS housing jelly got washed out? Leaked out? or Tesla decided to dump more Jelly/slime in later inverter assembly for additional condensation damage prevention?

Not sure, I checked CANBUS housing but it was still sealed and not leaking, also it had different consistency then the jelly from the components. Also I found the slime on top of the big O ring, it is way to thick to travel from the bottom to the top, also rest of components where not affected with this extra jelly. Check this picture it's from the top near the vent, it was way more but I wiped it off a little:

The cable glands leak rainwater into the inverter, it's a common issue. Be sure to test the HV Iso on those cable, use 500v and you can test from the inverter end (ie at the cables as shown above) or at the Rear HVJB under the rear seat, with the cables connected or disconnected from the LDU.

Low Iso on those two cables has been reported a number of times.

Yeah I iso'd the cables but they where fine (for now)

Note here for others following along: it's pretty likely that a groove or channel needs to be ground into the side of the casting to allow proper coolant flow out to the flyover tube. There's not much clearance between a typical aluminum cap and the casting when the taper tube is ground to flush. Perhaps you ground yours below flush? Or you ground/cut a groove?

My groove is a bit fancier than it needs to be, because I happen to have a hobby mill/drill, but any groove that is approximately the area of the flyover tube is sufficient:

View attachment 1051402 View attachment 1051403

Nice one! Yeah we made sure to have some clearance between the back of the cap and center hole. Think like a few mm's. Was thinking about a groove also but my partner in crime decided it was good enough without a groove

 

[howardc64]

Yes single lip

View attachment 1051879

Wow Tesla added a ton of grease on the shaft+seal area.

Yeah we greased them but think it's wise to pull the B+ B- cover again after like 6 months or so to check for moisture or replace the O rings anyway. After I think about it one cable had almost no resistance when pulling it out of the LDU, the one with less corrosion was a little bit harder to remove but also almost no resistance. You can even see that the left O ring has lost it's stretch:

View attachment 1051861

Mine is pretty snug but also don't have any of the corrosion patterns. Hear suction sound when pulled. 2013 MS 78k miles and lives in garaged space and no salted roads.

80-85% on average



Not sure, I checked CANBUS housing but it was still sealed and not leaking, also it had different consistency then the jelly from the components. Also I found the slime on top of the big O ring, it is way to thick to travel from the bottom to the top, also rest of components where not affected with this extra jelly. Check this picture it's from the top near the vent, it was way more but I wiped it off a little:


View attachment 1051855

Looks like Tesla definitely added some goo there. Mine 17 reman has a clean surface there.

 

[asavage]

2013 MS 78k miles and lives in garaged space and no salted roads.

Not true, Howard; since "Snowmageddon" of 2008, Seattle and surrounding Puget Sound began applying "salt" to the roads, when previous to that they never did. I grew up here, I know. And I resent that we now apply corrosives to the roads here, and that it all ends up in the bay.

You may not think that you're driving on "salted" roads, but they're definitely applying the stuff. And it hangs around for a while, too.

 

[Hank42]

Thanks @asavage for some tips that helped and also kept my attitude positive. Even though my stator windings were irreparable, my salvage ldu is in good shape. Just finished installing the qc bypass to keep it that way. Car drives like new! My inverter and gear box are still good, in case anyone needs parts . @asavage has an excellent write up on removing the rotor, my method was to place 2 4x4 blocks of wood paralell about a foot apart and place the du shaft side down such that the wood is supporting the weight on the stator casing and then, with 2 ppl, lift the unit about 6 inches and "drop" it onto the wood blocks. The inertia is enough to pop it free from the gearbox, and the wood is soft enough so as to not damage the housing.