The manufacturer does not supply internal parts for the Sunbeam 5891 Bread Maker. You will need to take it to a Authorized Sunbeam Service Center.
When Sunbeam stopped supplying the heating element for the model number 5891 Bread Maker, they did not replace it, and I have not been able to locate one.
My Bread maker is the Sunbeam 5891.
At any rate this kneader bar was to big for the bread pan.
I have checked with the manufacture for the kneader bar for the Sunbeam model 5891 Bread Maker. And they assured me that the part number 113494-001-000 Kneader Bar is the correct one for this model. You may have been sent an incorrect part by mistake. If so, you will want to contact our Customer Service Center @ 866-802-6383 an explain your situation to them and they will be happy to take care of you.
The kneader bar, part number 113494-001-000. Does have the D shape. If you could post the model number of your bread maker we may be able to help you locate the correct part for you.