I've owned my 2006 V8 for almost a year now. Since it was up to 110,000 miles and we tow a camper several times a year, I decided a replacement of drivetrain fluids was overdue. Some research on this site revealed some confusion on rear differential fluids, so I figured I would post what I used for this service:
: VW/Audi calls for G 055 025 A2. I used the Ravenol ATF T-IV that came with a Blauparts ATF fluid/filter kit
since it specifically stated it met the VW ATF spec. The kit came with 9 liters of ATF, but I was only able to add about 6.75L because I didn't blow out lines for the transmission cooler. With the towing we do, I do this service more often (2 years or 20K miles) so I'm OK with not replacing that last 2.25L.
VW/Audi calls for G 052 515 A2 and I elected to use this because it was rather unclear what other fluids would match the spec. The good news is that this 0.85 liter bottle is exactly the amount to add; just empty the bottle into the empty transfer case and you're done.
VW/Audi calls for the G 052 145 S2. This is a GL-4 spec gear oil and there are several non-VW brands available (for example, from the Ravenol GL-4 from Blauparts
). I elected to use the VW oil. You'll need 1 liter (1 bottle) and you'll use almost all of it.
Rear Differential (non-locking)
VW/Audi calls for the G 052 145 S2. This is the same as for the front diff, but only if you don't have the rear diff lock. This is where some of the threads here got confused. Some posts swore that the front and rear diffs took the same fluid and other posts swore that they took different fluids. As is so often the case, the answer is "it depends". By the way, you'll need 1.25L (2 bottles).
Rear Differential (locking)
VW/Audi calls for the G 052 196 A2 (synthetic). This is a GL-5 gear oil (Blauparts offers a Ravenol version
). My Touareg has a locking rear diff, so this is what I needed. I elected to use this VW oil this time since I was researching this through a local dealer. You'll need 1.6 liter (2 bottles).
For the rear differential, I could go with the Ravenol fluids next time and save ~$40. However, <shrug> this is an expensive vehicle with a complex drivetrain and the extra $40 to give it exactly what it wants doesn't bug me that much. Opinions on this will vary.
2006 Touareg V8