I'm looking at changing my transfer box and front and rear differential fluids. After some research on newtis.info, bimmercat.com and the internet, I've found the below information:
Transfer box (0.7L): DTF 1 75W GL-4 (83222409710)
Rear differential (0.8L): Hypoid Axle Oil G1 75W85 GL-4 (83222295532)
Front differential (0.6L): Hypoid Axle Oil G2 75W85 GL-5 (83222413511)
The transfer box is recommended to use the BMW DTF 1 fluid due to no viable 3rd party alternative being available, so I purchased 1L of 83222409710 to satisfy the 0.7L fill requirement.
However, for the rear differential, I've seen people recommend
Red Line MT-85 GL-4 gear oil as a replacement to the obscenely priced BMW G1 GL-4 gear oil. Same thing with the front differential and using
Red Line 75W85 GL-5 gear oil as opposed to the BMW G2 75W85 GL-5 gear oil.
What do you guys think? Anyone have any experience/knowledge with the fluids in the front/rear open differentials on our G30s?