360 Does replacing engine oil replaces differential fluid?

Hi everyone,

As I am replacing my gearbox fluid, I noticed that the gearbox area and differential area are technically separated from one another by this wall through which the lay shaft gear goes.

Also, there is a trap "49" right below the Differential area with a drain plug but it states "Olio Motore".

I was therefore wondering:
- when we drain the gearbox fluid via the drain plug "38" , do we also drain the Differential area? Seems weird to me as I cannot understand how the differential oil would go through the wall separating the differential and the gearbox itself
- Or is the differential actually bathed in engine oil (given the location of the Differential just above one of the Engine Oil drain)? So would replacing the engine oil leads de-facto to replacing the differential lubrication system?

To me it looks like the housing where the differential is, actually serves as engine oil dry sump as well. Am I right?

I know this is a bit of an existential question ;o)


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Thanks @eric355 , so you mean that all the Transmission Fluid present in the Diff area would go out via this tiny hole at the back of the gearbox? (circled in red - This is a 430 but architecture is almost identical).

Seems weird to me especially since the bottom of the Diff area goes quite deeper than this tiny hole and there seems to be no hole between the gearbox area and the diff area that is lower than this small hole.

So I am actually wondering whether changing the Gearbox fluid really does empty the differential oil.


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And inside the differential, again I see no hole (except above the screwed plate on the bottom right) that allows the oil below this plate level, to go back to the gearbox area.

So by which hole does the diff oil goes back to the gearbox area to be drained out of the system?

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Thanks @Doctor Mark, instead of making this passive aggressive comment, why don't you make constructive replies and share your great knowledge to "expand" mine and explain how the Transmission Fluid goes from the differential compartment to the gearbox compartment?

Thanks so much.

 

Thanks guys. My questions was a bit provocative as indeed that would sound crazy to use engine oil to lubricate the diff, but given some Ferrari designs that are questionable (ECU in then out then in etc,) and since some models of cars do so, one could wonder.

Unlike what @Doctor Mark believes, I know actually quite a lot and just opened the gearbox by removing the rear gearbox cover from my car yesterday, something I doubt many here have ever done. Some maybe I am asking a bit too technical question, but looks like nobody really knows.

That said, 24h after resealing my rear gearbox cover (as sealant 518 requires 24h of anaerobic environment to properly cure), I refilled my gearbox with 75W90 to see if it is leaking (I was unsure as the seal between the main gearbox housing and the interplate became slightly loose during the operation). What struck me is that I only managed to add back a bit less than 3L of fluid before reaching the "Max" level despite the gearbox being 100% empty (since I opened it fully at the back and could see it was totally empty).

Also what I noticed is that between the time I tried to replace the fluid, had my stupid "incident" with my rubber plug, and the time I removed the rear cover (yesterday), it took a good 3-4 weeks. And when I cracked open the gearbox yesterday, a good 1-1.5L of additional fluid came out through the seal and rear opening.

A 3rd point is that even 2 weeks after my incident, when I used a boroscope to check my rubber plug and tried to recover it, there seems to have been not that much fluid at the bottom of the gearbox.

These elements (only being able to add 3L in the gearbox despite the gearbox being open at the rear yesterday + the fact that not much fluid was at the bottom of the gearbox 2 weeks after my incident and that more than 1L of fluid came out 1 month later i.e. yesterday) suggests to me that we should probably let the gearbox fluid drip out for a few days (weeks?) before refilling it as looks like the fluid inside the differential takes a long long long time to come out.

I know that the manual recommends to crack open one of the hose and blow compressed air in it, but looking at Ratarossa's video, it seems there is far less than 1L coming out of these hose and from the heat exchanger above the engine. Would you be comfortable leaving 25% of dirty oil in your engine? I am not, especially for a gearbox.

If that is the case (that it takes a long time for the fluid to move from the differential to the gearbox compartment, then my question probably makes more sense as to how come there is no more obvious holes to transfer this fluid from one compartment to another.

But I hope @Doctor Mark will have the answer to this relatively simple question.

 

Thanks @GogglesPisano, that was indeed the plan (to run the engine before checking the level) but since I opened the box, I wanted first to fill the transmission and see if any leaks at room temperature. Then run the engine and do the transmission fluid level as per the manual, and check if there are any leaks at higher temperature (so plan is just to warm up the engine locally for 20-30 minutes and check for any leaks.

But my question is more about "how the diff oil gets evacuated and how long it takes to really get it out as looks like a good 1.5L is trapped in the system excluding the gearbox oil, meaning that doing a quick transmission fluid change leaves almost 35% of dirty fluid inside the system". Hence understanding through what passage the fluid moves from diff to gearbox area could help better understand how this gearbox works.

G

 

Well, i bought the car 1,000 km ago and was maintained all its life before by "Ferrari Official Officine".

I was shocked by how dirty the mesh filter was (see picture) so very much doubt we can trust all "Ferrari Official Officine".

There was obviously no way so much crass was built up in just 2 years and 1,000 km.

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So I personally think that we (the DIY guys) do a much better job at maintaining these that some Ferrari shops.

Also another key one was that the 2 oil drain plugs had Teflon tapes around the thread, which I guess is standard procedure in the "Ferrari Official Officine" world?

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So I do not think doing the opposite of what Ferrari shops do (i.e. drain the gearbox oil quickly and refill a few minutes later) and instead let all the crap drain out over a few days is really a bad thing.

G

 

Thanks @Rifledriver for your explanations that "Expand" my knowledge and confirms that this design is really weird and that replacing the gearbox fluid requires significant time and attention. But your response (that all the oil goes through this little hole) also suggests to me that actually the differential is never really drained properly since the hole is not at the bottom of the differential.

"Ferrari Official Officine" are the Official Ferrari workshops in Europe (snobism of calling themselves "Officine"), so not only do they charge crazy prices to do anything, refuse to provide quotes for work (based on the principle that "if you ask for quotes you do not deserve to own a Ferrari"), but despite this arrogance, re-use EUR 0.50 crush washers and use teflon tape on threads, and possibly charge clients for replacing transmission fluid without actually doing it and feel safe about it as users of the "Officine" is very unlikely to ever check his/her transmission fluid him/herself anyway :-(

 

Hmmm, not sure how this discussion went south this way and I am sorry @Rifledriver if you feel I was disrespectful. This was not my intention and thought my "Thank you" sounded as genuine as it was. I am very thankful to you for confirming what I thought was a rather surprising design (to have such a small hole for draining from transaxle to gearbox).

My comment on using Teflon etc. unfortunately reflects the fact that quite a few Ferrari dealers in Europe are quite pretentious and not helpful (had only one good experience vs 5 who did not even bother trying to be helpful, that gives you a ratio), borderline snobbish with people asking for quotes for instance. Possibly less the case in the US. Yet your "Its why so many are never properly drained or filled" tend to suggests that not all dealers are as patient and thorough as you are when it comes to doing this procedure.

And maybe I am an "hypersensitive prick" but I challenge anyone to make me think @Doctor Mark 's first post was kind or/or constructive.

I feel we are here to help each other, hence me posting suggestions on how to remove the rear gearbox cover step by step for instance including building a simple tool to create leverage. Maybe this is useless to 90% of the community, but could serve as reference to someone in 10-20 years if they mess up their gearbox refill as I did and avoid spending thousands to tow their cars to a Ferrari dealer and get the gearbox open.
Or sharing details of a great guy in France who can totally rebuild the 360 Spider hydraulic cylinders for a fraction of what some providers charge (and does not inflate his price 50% more vs Mercedes cylinders just because they come off a Ferrari for instance).

And thanks @RedNeck, I agree that this method is a good one, but personally I prefer filling with a syringe and sucking up any excess should it be too high. For the gearbox, there is also a question that the manual does not answer and which is "does the plug need to be screwed in to measure the level or should it just rest on the thread". Ratarossa says it has to rest on the thread and not to be threaded in. But this makes quite a big difference whether it is threaded in or not since the thread length is roughly 50% of the heights between the Min and Max level.

 

Thanks @flash32. I was referring to checking the transmission level though but I guess your "resting" (on the thread) applies to both the engine oil and the transmission oil, correct?

What I do not get on the Engine oil check level topic though is that your manual suggests "and wait five minutes after stopping", which seems aligned with what Brian says (If I understood his response correctly in one old post) whereas the manual that a lot of us here use states "Keep the engine idling" (picture below).

I used my manual technique (i.e. warm and idling) and filled 9.1L in total, which does not seemed crazy vs the alleged 9.95L capacity stated in my workshop manual as there was probably some left here and there).

So (1) I am not sure which one is right and (2) why are there discrepancies.

According to ChatGpt (who is very often wrong though):
- The oil level on car engines equipped with an oil sump should always be checked with the engine stopped, not idling.
- If you check the oil while the engine is idling, a significant amount of oil is circulating through the engine and hasn’t settled in the sump yet. This results in an inaccurate, typically low reading.



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BTW had a Casper mattress and really disliked it as smelled very chemically for 2 weeks so returned it LOL