I've been surfing different threads and am finding members are using a variety of different oils for their engines and lubes for differentials.  I own a 2019 Z8 Trail that, like all CFM's makes a lot of noise. What I would like to know is, what JASO certified engine oil and differential fluid are you running and has it quieted your gears down, even a little?

[2015 Z Force 800 53/Trail EPS]

For the engine I run Castrol Power RS or Power 1 4T 10/40 because of the reviews and it claimed to quieten the transmissions as well as make then shift easier. It does..noticeably. As for the diffs, the front I use Valvoline 75w90 synthetic but in the rear I am having a problem with it grinding itself into oblivion so I switched back to a conventional 80w140 and change it every 300 miles or so. That has slowed the problem and made it a little quieter. But all..it still kills my ears above 25mph. I'm going to have to start wearing ear protection...which is a ridiculous step to take because of a noisy drive train.     

I just passed 550 miles and have done one oil change.  I have never touched the differentials.  Snorkeled the air like NMK and am about to do the CVT snorkel.  All the driving has been on fire roads with an occasional rough trail.  Lots of high speed (40 to 50 mph) gravel roads.  What am I missing in maintenance?

[2015 Z Force 800 53/Trail EPS]

I just passed 550 miles and have done one oil change.  I have never touched the differentials.  Snorkeled the air like NMK and am about to do the CVT snorkel.  All the driving has been on fire roads with an occasional rough trail.  Lots of high speed (40 to 50 mph) gravel roads.  What am I missing in maintenance?

Better do those diffs..and soon. They make a lot of metal filings that kill bearings and seals....even ones on perfect shape.