Part number for O ring for front differential drain plug?
 

Hello everyone!

I'm doing both axle seals for the front differential. According to the directions on Audipages, there is an O ring on the differential drain plug, which I'd like to replace. I've searched the parts catalog and can't find the part number, so I wonder if anyone here can help with the part number or the specs for the o ring. Ideally, I'd like to purchase this before the job, so I have everything ready.

Thanks in advance for any assistance.

Are you referring to part #22 in the attached image? If so, the part number is 01V409057, and it comes with an o-ring.

I think that may be the one. I pulled up the PN, and two sizes came up. Could anyone confirm which size is correct? I see M18x1.5 or M12x1.5.

There is no size given for the D2 one, but the exact same part number used in the D3 has a size of M18x1.5. Also on the D3 parts list, it lists a separate seal ring, part number N0138321, size 18x22.

Thanks for the info, steamship. I found pictures of the N0138321 seal ring, and it seems to be a metal crush washer. While the diagram you posted and other pictures I've found show a flat-ish rubber O ring. I think I'm going to order the smaller M12 bolt/seal and report back.

The attached image is from the official parts catalogue for both the D2 and D3, and it does 'appear' like its a flat-ish o-ring. However, considering where its used, the colour might be misleading. Why not order both, so long as you can return the unused one.