Hi very new to the site so don't know if I've posted in the right place ! Sorry if so ! Could somebody help I've got a rs6 and there's a slight whirring sound come I think from from diff and a occasional screech when setting off from stationary! Checked diff oil and all ok ? Help or is it normal ?

[2015 Z Force 800 53/Trail EPS]

Not normal. Sounds like a bearing problem but check the wheel bearings and CV joints first. Might also drain the oil..sometimes there are tell-tale signs of bearing failures in the oil.

[2015 Z Force 800 53/Trail EPS]

=Cheers   Mk I will look in tomorrow I'm hoping it's not a bearing but if so is it a big job and do you recommend not to use it while it's like this  ?

Well, I recommend knowing exactly what it is. Then take whatever precautions or actions necessary. If it is a bearing somewhere, its grinding itself into dust. That's not something I would want to trust out on the trail. Wheel bearings not too tough to replace. Diff bearings and other parts require removal and disassembly. I bit more work and tools.