If you don't mind paying the $$$ for it you can just use the VW fluid. Shop around the net for a decent price. There are somewhat cheaper alternatives.
With that said VW doesn't make the fluid or even the transmission for that matter. The transmission is made by Aisin which is a Japanese company.
Use the "Search Community" rectangle at the top center of the page and you'll find lots of threads on fluids/capacities/instruction for servicing the 8 speed Aisin transmission.

 

 

Aisin Fluid is pretty inexpensive. Motul, Febi, LM, ROWE. etc...

 

Isnt Aisin owned b6 Toyota and uses the same fluid as their dealers supply

 

Same yes

 

Any idea of cheaper brands of transmission oil for 8 speed

 

See post #3.

 

Any idea of cheaper brands of transmission oil for 8 speed

Same yes

Aisin Fluid is pretty inexpensive. Motul, Febi, LM, ROWE. etc...

thanks. will check on it.

 

Just did my second flush (now 100K on the clock) via the bucket method, take a look here for all the details:

 

I need to do a drain and fill. Get this Ravenol Garbage out of my trans. Shifts bad with it, especially cold or under load at higher RPM. I don't trust Ravenol after some incident with them ( I was a supplier) and the lying they do. Company is not ethical IMO. Blauparts especially since I had to buy from them as they became the NA distributor. Ravenol does not work well in this gearbox.

Moving back to Aisin or Febi Bilstien.

 

The only hiccup might be (depending on how obnoxious this Ravenol stuff is) the .7L left in the cooler. If an issue pull the thermostat and drain the cooler too. You will have to do 2 top offs. Once during the initial flush and again after the fluid has gotten hot enough to refill the cooler.

 

Why not just "pre heat" the fluid?