Rear Differential

So it seems the rear differential shares fluid with the Haldex coupling?

No they are separate and use different oil. There are two separate drain and fill plugs. For whatever reason there does not seem to a maintenance schedule for the differential oil that I could find, but I plan to do it with every other haldex oil change.

I just changed my Haldex and only seen drain and fill plugs on the driver's side of the unit. I hope they were for the Haldex. The oil that drained out was still amber colored like the new fluid.

The rear "bevel" box, VW claims is a lifetime fluid, just like up front.

But, it's probably a good idea to change it 50,000 miles, with a GL-5 75w90 fluid.

Fuchs Sintopoid 75w90 is the factory fill. But Amsoil Severe Gear 75w90 is also a good option for about the same price.

The Fed said:

I just changed my Haldex and only seen drain and fill plugs on the driver's side of the unit. I hope they were for the Haldex. The oil that drained out was still amber colored like the new fluid.

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I hope so, too! The drain and fill plugs for the rear differential and Haldex are pretty close to each other, and this will be an expensive mistake! Photos of all of the drain plugs are here: https://forums.vwvortex.com/showthr...evel-box-haldex-and-rear-differential-housing

While that's a MK5, the plug position is the same.

I've replaced all 3 fluids. The front bevel gear fluid sees much harder life than the rear differential. I replaced the rear differential pretty early to get rid of the break-in material, but I won't touch it again until 100K. The front differential, I'll likely do every 40K, or every other Haldex fluid change (doing Haldex every 20K).