gear oil

Based on my limited research, the difference between GL-4 and GL-5 is the amount of extreme pressure additives. A lot of people say don't use GL-5 spec fluid in a transmission that calls for GL-4. One of the reasons given is that increased additives can cause corrosion to the brass...

One thing I’ve not been able to find any information about is the Amsoil Severe Gear forming an iron sulfide layer on parts. Does anyone have any additional information on this? I currently use Amsoil Severe Gear as I know it’s a great gear oil, but I’m curious to learn more about iron sulfide...

Hello folks, Here is VOA results for Hyundai 00232-19100 "WDCTF Hd G" SAE 75W Gear Oil used in 8 speed wet DCT. Viscosity at 100C is a bit low compared to similar Ravenol MTF-4 product (5.59 cst). Ravenol is the only aftermarket oil that I found has this spec, but I could not find it in US...