What trans fluid to run? 1997 VW VR6

[CagedVR6]

What fluid should i run in my 1997 GTI VR6. It has an O2A gear box calling for GL-4 fluid. I also have a quaife LSD. Right now im running redline mt-90 but on longer drives "like 45min-1hr" it will grind 2nd gear. Think the redline is too slipperly? Should i try non-syntheric? Thanks.

 

[mechtech2]

The Redline is made for good shifting. It is not a differential oil, but a manual transmission oil.
It is getting dated, however. There are many alternatives nowadays, depending on the viscosity that you want.
If you can use a synchromesh type fluid, they sure do shift well.

 

[unDummy]

MT90 is a 75w90 gear oil. If that is what you require, its is an excellent fluid and is no way dated.
If it has more then 30k miles, its simply time for another fluid change.

Amsoil also makes a 75w90 MTG if you want to switch brands.

What is the OEM requirement?