When exactly do you mean that the pump continues running? At end of the final spin when the machine should otherwise shut off? Or, if you are referring to the drain period after the agitated wash, the pump won't shut off immediately when the water has drained. It keeps running for a while into the rinse phase. It has to run during spin to drain the extracted water away. There are multiple spin periods during the rinse phase of the cycle, as well as the final spin. It does shut off a few mins into the final spin, then turns back on at the end when spin begins decelerating.

An abnormally noisy pump would indicate either that the bearings are getting bad (and it may be leaking a little), or a foreign object or lint/debris may be clogging the tub outlet and rubbing on the impeller.

The pump can be run either by advancing the cycle to the final spin, or test run separately in diagnostic mode --
With Power off, press and hold Wash Temp Down, then press Power at the same time. Should get two beeps and panel comes on. Press the Regular cycle button to turn the pump on (or off). Press Power to exit diagnostics.

You need to inspect the pump ASAP. A leaking pump can short-out and zap the controller board. Unplug the machine and lean it back for access beneath. The pump is a small electric motor with a fan on the bottom, mounted on a metal plate toward the right side under the tub. Do not remove the mounting plate. Disconnect the pump wires (two wires on a connector plug, separate ground). Find a plastic latch on the bracket near the pump head. Hold the latch released and rotate the entire pump counterclockwise (as viewed from beneath) to detach it from the plate. Have a large towel ready to catch the residual water that remains in the tub outlet. Examine the pump for signs of leaking (rusting or mineral deposits) or bad bearings. With the pump removed, look and feel for foreign objects or a lint/debris clog in the tub outlet opening.

The pump is Part Number 420325P. SearsPartsDirect.com carries F&P parts, or FisherPaykelParts.net. Or eBay sellers. A replacement pump should include a retrofit fuse to be spliced into one of the pump wires inside the control panel to help protect against zapping the board. Be sure to follow the directions exactly for your model (GWL15, add the fuse into the WHITE pump wire).