What is the best upper dishwasher rack to replace this model number?
Answer Linda, I believe your model should read DU850DWGX1 (850 instead of B50). The upper rack listed for your model is part number 3369903. Thanks!
How do I remove the end caps on the upper rack in order to replace the old rack with the new one?
To remove the endcaps on the rail of the upper rack, push inward on the front of the stop and once it releases pull out.
Is the upper rack #AP4114634 right for my Maytag dishwasher?
Yes, part number 99001454 upper rack is the correct part number for your unit.