Front diff lock oil change confusion

[tlerner87]

2017 CUPRA Leon ST 300 4Drive

Hi, hoping someone can clear up a bit of confusion Ive got.

At my latest service, main dealer flagged that my front diff lock oil needs to be changed every 3 years. Its the first time it's been mentioned and the car is 5 years old! However the Haldex service was done at 3 years old.

I asked a VAG specialist garage and they said:

"The front diff oil does indeed need to be changed at that interval, however, as your vehicle is 4 wheel drive, it is not changed on your vehicle. Only the Haldex oil is changed."

I presented this to the main dealer and they said:

"I have asked my Master Tech to check on the online workshop manual for your car, and he can confirm it has a front differential that is recommended to have the lock oil replaced every 3 years."

Does anyone know the definitive answer please, I'm confused.

Thanks!

 

[RUM4MO]

Remember that this is not "diff oil", if your car has an e-diff at the front, and I'm not sure that the 4WD cars do have, then it is only the Haldex coupling fluid that needs replacing every 3 years, this is only contained within the front Haldex unit that is connected to one of the drive shafts,

 

[SuperV8]

Remember that this is not "diff oil", if your car has an e-diff at the front, and I'm not sure that the 4WD cars do have, then it is only the Haldex coupling fluid that needs replacing every 3 years, this is only contained within the front Haldex unit that is connected to one of the drive shafts,

You don't have a 'front' Haldex on 4Drive. Also you don't have a front locking differential on 4Drive.
On the 4Drive you have 4x transmission oil reservoirs!;
The DSG oil
The front 'final drive' or 'bevel box' which has it's own oil fill and change interval.
The rear 'Haldex' oil
The rear differential oil

 

[SuperV8]

For 'what its worth' my info shows most versions of the final drive box listed as 'fill for life'! I hate that term - and would still change the oil at some point but it's certainly not a critical oil change like the rear Haldex unit or the DSG - as there are no friction plates just hypoid gear set; same as your rear diff.

 

[queen]

You don't have a front diff they must have it mixed up with the non ST cupra that has a front diff (VAQ).

 

[martin j.]

Looks like another dealer that doesn’t left from right.

 

[tlerner87]

Thank you all for the information, all makes sense. The confusion must stem from the maintenance schedule manual which says
"Front axle differential lock: Oil change (only Cupra models)" but they obviously mean front wheel drive cupra only! The dealer should have known that though.

Anyway, the DSG and Haldex services have all been done on schedule in addition to the usual major/minor services, so I think I'm ok.

 

[tlerner87]

For 'what its worth' my info shows most versions of the final drive box listed as 'fill for life'! I hate that term - and would still change the oil at some point but it's certainly not a critical oil change like the rear Haldex unit or the DSG - as there are no friction plates just hypoid gear set; same as your rear diff.

Can I just clarify which bits are listed as fill for life?

- The front final drive/bevel box?
- The rear final drive diff oil? Or is that changed as part of the same service where they do the haldex fluid? Or is it a totally separate service?

 

[RUM4MO]

You don't have a 'front' Haldex on 4Drive. Also you don't have a front locking differential on 4Drive.
On the 4Drive you have 4x transmission oil reservoirs!;
The DSG oil
The front 'final drive' or 'bevel box' which has it's own oil fill and change interval.
The rear 'Haldex' oil
The rear differential oil

Exactly what I suggested or guessed!

Edit:- I'd think that it is better to avoid calling the fluid in any Haldex component "oil" as its purpose is more to do with being a hydraulic forcing medium and nothing to do with lubrication - which is what most people consider an oil to be.

 

[SuperV8]

Exactly what I suggested or guessed!

Edit:- I'd think that it is better to avoid calling the fluid in any Haldex component "oil" as its purpose is more to do with being a hydraulic forcing medium and nothing to do with lubrication - which is what most people consider an oil to be.

You mentioned about a front Haldex unit - and the OP has a 4Drive. I was clarifying the 4Drive does not have a front Haldex/Locking diff.

The service manual calls the Haldex diff lock 'hydraulic forcing medium' OIL! (oil filter)
Also the Haldex fluid has 2x jobs -
1x as a hydraulic fluid in a piston to clamp the friction disc pack
2x as a lubricant in the wet friction disc pack & bearings

I think calling it Haldex oil is fine.

 

[SuperV8]

Can I just clarify which bits are listed as fill for life?

- The front final drive/bevel box?
- The rear final drive diff oil? Or is that changed as part of the same service where they do the haldex fluid? Or is it a totally separate service?

Fill for life quoted on the front bevel box (transfer box) OCN, OFN & OAV all say 'fill for life'
OFV doesn't say 'filled for life' and also has a slight difference in fill qty.

I presume this comment is referring to the OFV transfer box (all wheel drive coupling)

The rear final drive differential & rear Haldex unit are separate and require different oil specs.
I can't see any time/millage change interval for the rear final drive diff.
The Haldex unit and your DSG are the important oil change service items - as you have the friction lining material contamination and much more heat the oil has to deal with.

My manual gearbox is also 'quoted' as fill for life! (unless used by police - in which case 90,000km) but I still changed my oil around 90,000 miles.

 

[RUM4MO]

Okay, but BorgWarner tend to refer to this fluid as a friction enhancing, or similar, fluid, which tends to make sense as it will end up getting onto the faces of the friction discs and adding in lubrication at that point does not make much sense when controlled grip is the name of the game. The fact that it ends up collecting discarded bits of frictional material and some of that drops out into the base of the Haldex coupler sump - but some ends up being returned to the inlet of the hydraulic pump, and so frequent fluid changes are required to prevent the hydraulic pump ending up clogged up with debris.

VW Group refer to this fluid as a "High Performance Gear Oil", so yes, calling it "oil" does work, but it can leave owners with limited technical knowhow with this quandary - "does the diff oil need changed or not".

I'd hope that no "Jonny go faster" types heads for that fluid instead of proper gear oil as a good upgrade, based on its official title!

 

[RUM4MO]

By the way, seeing as DSG fluid changing has now been mentioned, it will only be the DSG gearboxes that have "wet" clutches that will need frequent fluid changes, for the same reasons as for the Haldex couplings, some DSG gearboxes have "dry" clutches so do not need frequent fluid changes, just something else to change out for as not all DSGs are the same.

 

[RUM4MO]

Looks like another dealer that doesn’t left from right.

My VW dealership service department initially turned down my request for them to replace the cam belt on my 2000 VW Passat 4Motion as it did not have a cam belt, just a chain!
A master tech was called in and he backed up the service person!
I then found the need to point out that all the V6 petrol engines in this version of Passat used the Audi engine, and not the VW narrow angle V6 petrol engine, so they gave in and carried out that work!
Sometimes they do worry you, this was a well thought of VW dealership.

 

[adam davies]

My VW dealership service department initially turned down my request for them to replace the cam belt on my 2000 VW Passat 4Motion as it did not have a cam belt, just a chain!
A master tech was called in and he backed up the service person!
I then found the need to point out that all the V6 petrol engines in this version of Passat used the Audi engine, and not the VW narrow angle V6 petrol engine, so they gave in and carried out that work!
Sometimes they do worry you, this was a well thought of VW dealership.

Unfortunatley people rely and put their trust in dealerships, when in reality the majority of their work is oil changes and discs and pads any major mechanical work gets outsourced and engines arent repiared just replaced. One qualified mechanic with a group of young lads who havent developed brains yet. People are much better of using local specialists who know the cars like the back of their hand and can fault find and not be told to do things a certain way by a manual written by a guy in am office.
Rant over

 

[SuperV8]

Okay, but BorgWarner tend to refer to this fluid as a friction enhancing, or similar, fluid, which tends to make sense as it will end up getting onto the faces of the friction discs and adding in lubrication at that point does not make much sense when controlled grip is the name of the game. The fact that it ends up collecting discarded bits of frictional material and some of that drops out into the base of the Haldex coupler sump - but some ends up being returned to the inlet of the hydraulic pump, and so frequent fluid changes are required to prevent the hydraulic pump ending up clogged up with debris.

VW Group refer to this fluid as a "High Performance Gear Oil", so yes, calling it "oil" does work, but it can leave owners with limited technical knowhow with this quandary - "does the diff oil need changed or not".

I'd hope that no "Jonny go faster" types heads for that fluid instead of proper gear oil as a good upgrade, based on its official title!

'Wet' clutches are common with motorbikes and auto boxes - I know it seems strange having an oil/lubricant on the friction face but friction/tribology is a complicated beast!
Brake pad friction materials for example use many compounds - and one of said compounds is carbon, and one of its jobs is acting as a lubricant! so the Tribologists adjust the lubricants and friction modifiers in the friction material to get the desired performance - it's not just about the highest friction coefficient.

 

[SuperV8]

By the way, seeing as DSG fluid changing has now been mentioned, it will only be the DSG gearboxes that have "wet" clutches that will need frequent fluid changes, for the same reasons as for the Haldex couplings, some DSG gearboxes have "dry" clutches so do not need frequent fluid changes, just something else to change out for as not all DSGs are the same.

The DSG in the Cupra is a 'wet' type.
The 'dry' DSG's are reserved for eco low torque engines.

 

[RUM4MO]

The DSG in the Cupra is a 'wet' type.
The 'dry' DSG's are reserved for eco low torque engines.

The "dry" DSGs are reserved for eco low torque engines is logical, but I'm sure that I've read that the 7 speed in the 2019 Cupra, which is DQ381-7F, is not subject to frequent fluid changes, which kind of, if true, tends to hint that this version of DSG is "dry" type - unless anyone can say otherwise, I'm only slightly "involved" in this mainly as a "protector" of my daughter's car/wallet as in trying to make sure that what should get done, does get done in time.

 

[SuperV8]

The "dry" DSGs are reserved for eco low torque engines is logical, but I'm sure that I've read that the 7 speed in the 2019 Cupra, which is DQ381-7F, is not subject to frequent fluid changes, which kind of, if true, tends to hint that this version of DSG is "dry" type - unless anyone can say otherwise, I'm only slightly "involved" in this mainly as a "protector" of my daughter's car/wallet as in trying to make sure that what should get done, does get done in time.

that is also a wet DSG.

 

[RUM4MO]

From TPS website just for interest:-
Service intervals:

The table below gives an overview of these gearboxes and their service intervals:

Gearbox type	Gears	Service interval	Fluid*
DQ200	0CW	7-speed	No service interval	G 055512A2
DQ250	0D9	6-speed	40,000 miles - Fluid and filter	G 052182A2
DQ381	0GC	7-speed	80,000 miles - Fluid only	G 055529A2
DQ400**	0DD	6-speed	40,000 miles - Fluid only	G 052182A2
DQ500	0DL	7-speed	40,000 miles - Fluid only	G 052182A2
DQ500	0BH	7-speed	40,000 miles - Fluid only	G 052182A2
DL382	-	7-speed	40,000 miles - Fluid only	G 055529A2
DL501	-	7-speed	40,000 miles - Fluid and filter	G 052529A2

* Part numbers shown are for 1 litre bottles, a 20 litre product is also available
** Fitted to hybrid models, only EV certified technicians should work on these vehicles



Top tip: always refer to the Erwin Workshop Manual for the correct vehicle-specific interval, servicing instructions and filling capacities.

Curiously, for DQ381, which has a filter it seems, no recommendation to include it in the 80,000miles fluid change, though I'd think some people will change the filter along with the fluid at some lower mileage, but as the filter is not listed in the parts listings, maybe it needs to be bought in via a BorgWarner agent, if in deed it exists and is possible to replace while the box is fitted to the car. Does this not begin to sound like what is the official VW Group take on scope of Haldex servicing against what trans experts recommend, ie VW Group recommend "quick and cheap" servicing on trans units, which might be why I keep seeing an evolving "DSG going for repair" frame in my normal VW Group parts department, ie they started off being single stand alone transit frames, and then evolved into stackable transit frames - or even frames to hold 2 DSG units and now stackable, saves a lot of space in the departure area, maybe because lots of them are being moved out for repair. That constant sighting of DSGs waiting for collection has always worried me a bit, maybe company cars get abused more than privately owned ones?