Desperate for help - need to remove impeller screw

[fustrated]

My dishwasher will not drain, inspected hose, check valve - no problems.

Now attempting to inspect lower impeller - but can't remove impeller screw from upper impeller.  

Can't get enough of a grip on the impeller to keep the motor shaft from turning to get the screw out.  The upper impeller is made out of plastic and any grip seems to strip away rather than holding it in place.

I see in some forums folks suggest breaking the upper impeller but I don't see how this will help - the screw would still be difficult to remove.

Very close to calling a technician - any assistance / suggestions would be greatly appreciated.

Model Number: DU915PWKQ0

[Repair-man]

You just need something to hold the impeller while the screw is removed. I generally throw a couple of wraps of friction tape around the impeller body so my Channellock pliers can grip it without damage.

[cjorden]

I tried the channel locks. It started to damage the impeller. I used the channel locks to hold a 15/16" socket (1/2" drive) on to the impeller, then put a 1/4" socket with an extension down through the 15/16" socket. Rotated the screw right out, then back in when I made the repairs.
I also put friction tape around the 15/16" socket so the channel locks could get a better grip and not scrape up the socket.

[TJW]

Where does the drain hose run to from pump motor assy. Siphon break, disposal, or straight to drain pipe?

[BrntToast]

the drain hose on that machine is clamped onto the check valve assembly which screws into the pump housing
remove clamp and drain hose, then unscrew the check valve assemby
there is a lil plastic retainer across the opening of the valve assembly, grasp it with pliars and it pulls out, you can then remove the rubber flap inside the valve assembly and also remove whatever has become jammed inside it

its very common to get things stuck in this spot

the thing you wanna unscrew is #15 on page 5 of the parts breakdown you posted