What makes DSG fluid unique?

[JETaah]

This is the second customer that has come in for DSG fluid service where I have found RED ATF in the trans. Neither car is showing ill effects from the use. And, if they were getting a fluid change then, it has been in service for ~ 40K miles. The most recent car is a 2010 Jetta TDI with 99K miles on the clock.

This time I was able to get some info on what fluid was used.
The shop that did the previous service claims that they use BG Products p/n 312 Universal fluid in all the VW automatics. Either they don't know that the DSG transmission is not a typical torque converter type or they just say "The hell with it. We buy fluid by the drumfull and that is what we use" ....I am not sure. The customer is now a bit worried about what might happen to his tranny on the long term from using this.

BG Products actually does make a DSG specific fluid p/n 319 and it is amber colored.

Both transmissions have wet clutches, right?

What is the difference between the two where it requires a specific fluid for the DSG?
Is typical RED ATF suitable as a differential lube?

 

[JETaah]

BTW...
The shop that did the previous fluid change is an authorized VW dealership....among other brands.

 

[Franko6]

The DSG fluid is a relatively thin GEAR OIL. The transmission oil is totally different characteristics.

But same for me, we have seen ATF, Tiptronic fluid- red stuff, used in the DSG transmission with no apparent ill effect. It is thinner and will allow better heat dissipation, but there is no way ATF fluid is good for hypoid gears. I think it will fail at the contact point between gear sets.

 

[Drivbiwire]

High quality EP/HP additives without friction modifiers to permit use with wet clutches. Also compatibility with yellow metals ie synchronizers.

Viscosity and thermal stability are a very high priority due to internal clutch temperatures which exceed the thermal limits of nearly every transmission fluid out there. DSG Fluids must be a high quality synthetic for this reason alone. Operating range is -67F up to 356F.

The system is designed to keep temps below 293F, but actual temps at the friction surfaces will far exceed this temperature thus having a fluid with high stability is critical.

 

[GreenLantern_TDI]

I was always told growing up... ATF could be used in a manual tranny or a power steering unit. But not visa-versa.
For what thats worth.

 

[Drivbiwire]

There is a big difference in wet clutch function in a DSG, just like a motorcycle it's the primary clutch, where in a regular automatics the clutch packs are not subjected to extended partial engagements which generate tremendous heat.

Even in a motorcycle the clutch does not drag like in a DSG to replicate the "Creep" of a conventional automatic.

The DSG does not use planetary gear sets like a conventional automatic, planetary gear sets place far less stress on, and demand less of fluid viscosity across wide ranging temperatures in terms of shear strength requirements than does a conventional gear box like the DSG is.

The DSG has a lot in common with a motorcycle transmission using wet clutches, the difference is the extended partial engagement of the DSG clutch system that generates the stress which drives the standard for the fluid.

 

[CNGVW]

Why would you chances wracking a DSG by use the wrong fluid?
Lets look at the valve-body I have replaced 3 this year on DSGs at the tune $1400 parts plus labor $500 . So if you cook one you could look at $5000 to $8000 to save $30!!

 

[Hyde7278]

This is the second customer has come in for DSG fluid service where I have found RED ATF in the trans. Neither car is showing ill effects from the use. And, if they were getting a fluid change then, it has been in service for ~ 40K miles. The most recent car is a 2010 Jetta TDI with 99K miles on the clock.

This time I was able to get some info on what fluid was used.
The shop that did the previous service claims that they use BG Products p/n 312 Universal fluid in all the VW automatics. Either they don't know that the DSG transmission is not a typical torque converter type or they just say "The hell with it. We buy fluid by the drumfull and that is what we use" ....I am not sure. The customer is now a bit worried about what might happen to his tranny on the long term for using this.

BG Products actually does make a DSG specific fluid p/n 319 and it is amber colored.

Both transmissions have wet clutches, right?

What is the difference between the two where it requires a specific fluid for the DSG?
Is typical RED ATF suitable as a differential lube?

Checked BG's website and dont see a DSG fluid or a p/n 319

 

[JETaah]

http://www.dcsbg.com/wp-content/uploads/2014/07/319-Product-Flyer.pdf

 

[oilhammer]

The DSG fluid is a relatively thin GEAR OIL. The transmission oil is totally different characteristics.

But same for me, we have seen ATF, Tiptronic fluid- red stuff, used in the DSG transmission with no apparent ill effect. It is thinner and will allow better heat dissipation, but there is no way ATF fluid is good for hypoid gears. I think it will fail at the contact point between gear sets.

There are no hypoid gears in the 02E DSG, or in any FWD transverse VAG transmission, nor any transverse FWD transmission of any kind in any manufacturer that I can think of. Hypoid gears (bevel cut type) are used to change direction of rotation. Since the crankshaft turns the same orientation as the wheels on transverse applications, there is no need for hypoid gearsets in these cars. They use simple helical gears for the final drive, and conventional spider gears for the differential gearset.

This is why the transverse VAG manual gearboxes require a different lubricant than the longitudinal units, and the final drive (which is separate) on the automatics is also different from transverse to longitudinal.

I suspect that the DSG's ATF is somewhat unique, or at least, unique to that "type" of gearbox (there are others besides VAG's), is because it must meet the requirements of both a high stress shear load manual gearset with brass synchronizers (the 02E uses double synchros on some gears) as well as the low viscosity requirements for the ATF pump and hydraulic actuators and fluid cooler as well as small ports being pumped through the M-unit and clutch housings. The 02E is not merely "splash lubed" as most manuals are.

That said, there are lots of manual transmissions that get spec'd ATF for use in, typically of the lighter duty variety (but not always). Some newer cars, like Honda and GM (which in GM's case, could be an Aisin, Borg-Warner, Isuzu, Getrag, or Tremec supplied) manual gearbox specify a high quality, low viscosity synthetic lubricant like VAG does.

Ford uses what they call "Motorcraft Dual Clutch Transmission Fluid" in their DSG-type boxes, which are made by Borg-Warner (the same people that assisted with the 02E) and are controlled by Continental. These are, however, a dry-disk type transmission. So again, I think much of the special fluid type revolves around the blend of conventional automatic transmission type controls (pump, cooler, solenoids, valves, etc.) and conventional manual type gearset needs (helical gears, synchros, etc.).

Personally, I think it is dumb to second guess something as simple as fluids. Because if the cost of the correct stuff versus some cheaper stuff is your thing, then Volkswagens (and German cars in general) are probably not your best choice.

 

[Drivbiwire]

Output gear and differential:

 

[jasonTDI]

You can't or shouldn't use conventional motor oil in a motorcycle. Ever. Not if you don't want to replace the clutch all the time.

 

[jasonTDI]

Unless it's a BMW or other bike that uses an external dry clutch. (none being built since 2013)

 

[belome]

You can't or shouldn't use conventional motor oil in a motorcycle. Ever.

... if they have friction modifiers. Many many many motorcycle people use conventional Rotella in their bikes.

Back in the day, the only oils that did have friction modifiers were of the 10w-30 weight.

/Oh god, sucked into an oil thread... make me stop

 

[GreenLantern_TDI]

Hey to throw my hat in here. Im now a card carrying AMSOIL cult member. Got it when i ordered my oil bypass kit.
If you run AMSOIL in the DSG it will heal it from with.. ie no more oil changes needed. AMSOIL.

 

[JETaah]

The owner of the last car has just related to me that he sensed a hesitation when shifting from DRIVE to REVERSE that was not there prior to the fluid change by me.

I am wondering if the transmission has adapted to running with the red fluid's characteristics and now needs to have a basic settings recalibration done.

He has also been in contact with the rep at BG discussing this situation. I believe he is going to get with a shop that has a fluid replacement/cleaning machine to force out the entire fluid and flush the trans. There has got to be 2+ liters of the BG 312 ATF still in the trans mixed with the DSG specific fluid.
On the other hand, The BG rep also told him that he had talked with one of their chemists and that the new BG 319 DSG specific fluid is a newer product for them and that prior to that, they supplied shops with the BG 312 ATF for DSG applications.

 

[Wankel7]

You can't or shouldn't use conventional motor oil in a motorcycle. Ever. Not if you don't want to replace the clutch all the time.

That simply is not true. As long as the oil does not have friction modifiers you are good to go.

 

[Drivbiwire]

There is no trapped fluid, the total trapped fluid in the trans is less than a few ounces, this is by design.

The only place fluid is trapped is in the filter housing, and this is probably in the order of .2-.3L

The rest of the fluid completely drains to the sump when the transmission is off.

If the BG fluid is correct, then there is no adaptation required...

I stick with only APPROVED DSG fluids by the OEM suppliers, for that very reason (to prevent operating issues for customers).

 

[JETaah]

Hey to throw my hat in here. Im now a card carrying AMSOIL cult member. Got it when i ordered my oil bypass kit.
If you run AMSOIL in the DSG it will heal it from with.. ie no more oil changes needed. AMSOIL.

You try it first. Let us know how it goes.

 

[oilhammer]

There is no trapped fluid, the total trapped fluid in the trans is less than a few ounces, this is by design.

This is not true.

Dry fill is 7.2 liters, service fill is 5.2 liters (source: Alldata).

Also, I've let the 02E drain OVERNIGHT with no filter, and no fill tube funnel, and when I went to open up the front cover for an M-unit replacement, a significant amount more fluid comes out. And even more comes out when you pull the M-unit loose. Easy to see why, as the M-unit sits in a cavity in front of the case that hangs down lower than the gearcase portion where the drain is.


There is also more inside the clutch housing (again, I've done a few of those, too). There is no way it could drain out into the transmission case to wear the drain is, even if it sits.

So I would say Alldata's figure, which is taken from VAG's own published information (which I have at home) is pretty accurate.

 

[JETaah]

All I can tell you is that I drained 4.5+ liters of ATF out, filled with 5 liters of DSG fluid and the excess that drained out after warm up was pretty near as red as the original fluid.

 

[oilhammer]

All I can tell you is that I drained 4.5+ liters of ATF out, filled with 5 liters of DSG fluid and the excess that drained out after warm up was pretty near as red as the original fluid.

Yep, that's because there was another ~2 liters of wrong ATF in there.

Been there, done that, and it takes about 4 services to get it all cleaned out, since there is no adapter (that I know of) for the 02E's cooler to flush it all out. I have the adapters for the 096/01M and 098/01P as well as for the 01V/01L. Nothing for any of the Jatco or Aisin boxes, either.

 

[JETaah]

The BG rep said that they do it through the filter opening. I don't recall if it is an adapter.

 

[jasonTDI]

That's Rotella. Diesel oil. Different than gas car oil. That's why I said DON'T. Someone might do a search, read that statement and go "hey! that's a good idea! cheaper!" and then learn a hard lesson.

 

[jasonTDI]

... if they have friction modifiers. Many many many motorcycle people use conventional Rotella in their bikes.
Back in the day, the only oils that did have friction modifiers were of the 10w-30 weight.
/Oh god, sucked into an oil thread... make me stop

and lol on the oil thread comment! ahhh The days of the off topic anything goes section.

 

[jasonTDI]

That simply is not true. As long as the oil does not have friction modifiers you are good to go.

Pretty much only Diesel oil. Basically ALL gas car oils do. So stating that is OK is a bad thing for someone that can't search or does not know if they are in the oil or not. You give the average person with zero or 5% mechanical knowledge too much leash and expensive things happen.

 

[jasonTDI]

There is no trapped fluid, the total trapped fluid in the trans is less than a few ounces, this is by design.

The only place fluid is trapped is in the filter housing, and this is probably in the order of .2-.3L

The rest of the fluid completely drains to the sump when the transmission is off.

If the BG fluid is correct, then there is no adaptation required...

I stick with only APPROVED DSG fluids by the OEM suppliers, for that very reason (to prevent operating issues for customers).

I've pulled the front case to do mecha units and lost a solid liter.

 

[jasonTDI]

There are at least 3 other DSG fluids available, specific for the trans. Any they are cheaper than VW by a couple $$ a liter. Honestly....so what if it's $12? every 40K or so isn't a big deal.

 

[GreenLantern_TDI]

Could prob just run AMSOIL 5w40 as engine oil and as DSG fluid. Never have to change it again. AMSOIL.

 

[GreenLantern_TDI]

508 huh?
Back to DSG OIL. I purchased the LIQUI MOLY 8100 for my DSG. Hey do you think there is a way to put a AMSOIL Bypass filter on the DSG and run 100,000 mile Change intervals?