Originally Posted by
Rick_D
...synth gear oil is a popular substitute for the Shimano stuff--Royal Purple and Red Line are popular.
I've used Royal Purple 75w-140 in my Alfine 11 for around 10,000 miles with no problems. I used the Shimano oil for the first change; a kit with the necessary syringe and tube came with enough for the flush and fill. As far as I could tell, the only real differences were color and price. I also use this oil for dipping my Nexus gears once a year.