5 speed manual gearbox oil spec - stiff shifts when cold

[the sheep]

The gearbox on my 2003 A6 C5 1.9 tdi AWX (125,000 miles) is increasingly difficult to engage a gear, particularly when cold and mostly first. This seems to be common problem across a few models and some have suggested that an oil change, sometimes to a thinner oil gives a big improvement.

It's a 5 speed gearbox with code FHN. I phoned about the oil at a local Audi garage who seemed to be recommending G052 911 A2 SAE 75W 90 however I was passing another Audi garage on Monday who said they had the right oil in stock. The oil they provided was G052 532 A2. The G052 911 A2 did show up on their system but they said they never use it and therefore didn't stock it. To confuse things further I've heard that there are also thinner oils produced by VAG specifically to improve the stiff shifting.

So, does anyone know the correct gear oil for a 2003 A6 C5 1.9 tdi AWX with 5 speed manual FHN gearbox? If there are options is there one that is more likely to resolve the sticky gearbox I seem to have when cold?

Any help would be appreciated. So far I've found the following useful pages however I'm still not confident of the oil for my particular model:

G052 911 A2 / 3H gearbox oil 170,000 mile change to fix crunch
http://www.audi-sport.net/xf/threads...ox-oil.100962/
http://www.audi-sport.net/xf/threads....201592/page-2
Audifans.net: You are using an invalid IP
Volkswagen Oil Specifications - oilspecifications.org
stick with G52 in your tranny - here's why... - Page 9 - TDIClub Forums
http://www.partsfan.com/audi/me/0000...0/3/00/300010/

[Gazwould]

Do not let yourself get ripped off by purchasing the dealers expensive gearbox oils as you will need 3 x 1L bottles .

75W90 is oe so going to 75W80 will improve your cold shifts , it's down to the gearbox oil thickening up with age and there not being a service interval because they decided to call it a life fluid.

This is what you need .

[Gazwould]

Both Castrol Syntrans Transaxle 75W90 and Fuchs TITAN Sintofluid 75W80 carry the 911 spec .

But at 40°C there's a big difference in ( cold ) viscosity .

Castrol 75W90 is 78 mm2/s
Fuchs 75W80 is 49 .8 mm2/s

[rowdy-999]

Loads of aftermarket gear oils carry the VW approved code etc, but if ever compare the 2 oils you'll see a big difference in viscosity. When I changed the gearoil in my 6sp manual box - 130hp engine, the OE stuff is like water. I got an 'approved' oil that was like treacle comparison. I ended up filling it with a bog standard ATF because it had the same viscosity figures.....I'm not talking the 75w90 number, but the factory figures off the spec sheet.
I ran that for over 4 years, 50k with no problem, and the gear changes were silky.

[the sheep]

Thanks for the feedback guys, I was originally just going to get some OE spec oil as suggested by Gazwould but had heard concerns that viscosities can vary significantly (also mentioned by Gazwoukd and rowdy-999). At the time, this thread had put me off going for them though:

stick with G52 in your tranny - here's why... - Page 9 - TDIClub Forums

I thought I'd play it safe and pay the extra for piece of mind that it was the correct oil and just go with the dealer stuff which is why I'm a little confused that they seem to be recommending different oils themselves. The first thing I need to figure out is whether the recommended OE oil is G 052 911 A2 (as seems to be recommended here http://www.audifans.net/ftopict-20098-.html and the first dealer) or G 052 532 A2 (as provided by the other dealer) then I can see how similar aftermarket options are to the OE oil.

If the oil recommendation is G 052 532 A2, this thread ' http://www.audi-sport.net/xf/threads/manual-gearbox-stiff-gear-changes-when-cold-2-0-tdi-s-line.201592/page-2 ' says that G 052 171 A1 is a lighter version of G 052 532 A2 used to improve shifting which would be exactly what I'm after. It also says that the G 052 171 A1 is Fuchs Titan Sintofluid SAE 75W - 80 which is exactly what Gazwould recommended above for G 052 911, maybe they are very similar?

[the sheep]

Spoke to another Audi garage today who confirmed that the FHN gearbox uses the G 052 532 which I already have. He also convinced me not to try another thinner oil. Seeing as I already have the G 052 532 I"m going to give that a shot and if it doesn't make a significant improvement swap it for the Fuchs Titan Sintofluid SAE 75W - 80.

For reference Opie Oils states that the Fuchs Titan Sintofluid SAE 75W - 80 suits both the G 052 171 and the G 052 911 so they do seem to be at least very similar. There are some links that imply that the Fuchs Titan Sintofluid SAE 75W - 80 is also the stuff in the VW bottle.

Fuchs TITAN SINTOFluid SAE 75W-80 Syn manual Gear Fluid

One final question, does anyone know the fill level for the FHN gearbox? The link below seems to imply it's either 7mm or 1mm below the filler.

http://www.audifans.net/ftopict-20098-.html

[Gazwould]

Opie Oils are a little out of date for the 171 spec shifted to TITAN SINTOFLUID FE SAE 75W a very slightly thinner ( cold viscosity ) 40°C at 40.8 mm2/s compared to TITAN SINTOFLUID SAE 75W80 being 49.8 mm2/s .

Remember Castrol 75W90 is almost double the viscosity at 78 mm2/s .

What's annoying is there is no oil data sheets on the dealer oem stuff to make an informed decision .

[Brownieaj]

Did you manage to resolve the gearbox issue by any chance? My 2005 model has a particularly slow change up to second and I was pondering the benefits of an oil change and maybe coining thinner at the same time.

Many thanks.