Z1 is still in the rear diff of the RDX but DW-1 in the transmission.
I'm going to drop the RDX off at the dealership for the rear diff, don't feel like getting under there for 80 bucks.
Z1 is no longer produced. Any vehicle with SH-AWD has now been moved to DPSF (Acura AWD Fluid) for the rear diff. Rear diff is super easy, not worth $80.
Are you still on Z1 in your RDX or have you gone to DPSF? If you're on DPSF did you notice any difference?
Is Honda specifying the DPF-II now in differentials once requiring Z1?
In SH-AWD vehicles Z1 used to be used in the auto trans as well as rear diff. The specification has diverged now, DW-1 in the trans, DPSF in the diff.
To answer my own question I found a thread on mdxers. Someone bought Honda Dual-Pump Fluid II (DPSF II?) as well as Acura AWD Fluid (DPSF) to find out the same thing. Apparently they look the same but smell different. So I guess they're not the same.