How to Install Lower Wheel Assembly WP99002780 in a Whirlpool Dishwasher
Quick answer: Slide the lower rack out of the tub and turn it over. Release the old wheel assembly from the rack wire by prying its retainer open, then push WP99002780 onto the wire until the retainer snaps around it. Confirm it spins, put the rack back on the tub lip, and roll it fully in to check clearance.
Lower wheel assembly WP99002780 is the roller that lets the bottom dishrack in Whirlpool-family dishwashers, including many Maytag and Amana models, glide over the tub lip and back into the wash chamber. The manufacturer describes it as a dishrack roller that attaches to the rack so you can roll it in and out. When a wheel wears flat, splits at the hub, or loses its retainer, the loaded rack drops on that corner, grinds on the tub floor, and can stall the lower spray arm.
Replacing the wheel is quick and does not involve any plumbing or electrical work. The rack comes out, the old wheel is released, and the new assembly presses on. What makes this job go smoothly is checking all the wheels at once and making sure the retainer on each new wheel fully closes around the rack wire. This guide is for the lower rack only. The upper rack on these dishwashers uses a different wheel that rides inside a side rail.
See part details and every compatible model: WP99002780
- Wait until the dishwasher is cool. Racks come out of a heated dry cycle hot enough to blister skin.
- Wear gloves. Bare wire on an older rack has sharp edges where the coating has worn through.
- Set the rack on the floor to work on it. A rack balanced on the door can fall and pinch fingers.
- Keep the screwdriver tip pointed away from you while prying the retainer open.
- Do not run the dishwasher with a wheel missing; the rack can drop onto the spray arm and crack it.
Tools and Parts You Need
- Lower wheel assembly WP99002780 (one per worn wheel)
- Flat-blade screwdriver
- Work gloves
- Towel or cardboard to protect the floor and rack
- Needle-nose pliers
- Flashlight
- Scrub sponge and white vinegar for cleaning the tub lip
Step-by-Step Installation
- Pull the lower rack out Open the door and roll the bottom rack forward until the wheels drop off the tub lip. Lift it free and place it upside down on a towel.
- Check every wheel Spin each one. Note any that wobble, drag, sit crooked, or are cracked around the hub. Also look for a rack wire that is bent where a wheel mounts.
- Release the old wheel assembly Insert the screwdriver blade between the wheel retainer and the rack wire and lever the retainer open until the wheel comes off. Pull any broken plastic left on the wire with needle-nose pliers.
- Clean the wire Wipe scale and grease off the mounting point on the rack wire. The new retainer needs bare, clean wire to lock properly.
- Position WP99002780 Hold the assembly so the open retainer faces the wire and the wheel faces outward, in the same orientation as the wheel you removed.
- Press the assembly on Push the retainer over the rack wire with steady palm pressure until it snaps closed. Tug the wheel to confirm the retainer holds.
- Do the other wheels Replace every wheel that failed inspection so the rack sits level on all of them.
- Reinstall the rack Flip the rack upright, set its front wheels on the tub lip rails, and roll it all the way in. Make sure it does not touch the lower spray arm or the door.
- Run a short cycle Start a rinse cycle and listen for scraping or a stalled spray arm. Silence means the rack is riding at the right height.
Fit Checks Before You Call the Job Done
- WP99002780 spins freely with no wobble after the retainer snaps closed.
- The retainer cannot be pulled off the wire by hand.
- All wheels are the same height so the rack sits level in the tub.
- The rack rolls fully in and the door closes without pushing the rack.
- Your dishwasher is one of the listed models, such as MDB4651AWS0, ADB2500AWS40, or MDB8951BWS41.
- The lower spray arm turns freely under the rack after installation.
Common Mistakes to Avoid
Using an upper rack wheel on the lower rack The upper rack wheel is a different assembly built to ride in a rail. WP99002780 is specifically the lower wheel.
Bending the rack wire while prying Pry against the plastic retainer, not the wire. A bent wire will not hold the new wheel straight.
Reusing a cracked retainer wheel A hairline crack in the hub grows fast under a loaded rack. If it is cracked, replace it now.
Leaving scale on the mounting point Mineral buildup keeps the retainer from clicking shut, and the wheel falls off during the next cycle.
Skipping the spray arm check A rack riding low on a bad wheel can stop the spray arm. Always spin the arm after reinstalling the rack.
Troubleshooting After Installation
Wheel falls off after installation The retainer did not fully close or the wire is bent. Remove the wheel, straighten the wire with pliers, clean it, and snap the wheel back on until it clicks.
Rack scrapes the tub floor Another wheel is worn flat or missing. Flip the rack again and compare all wheels for equal height.
Lower spray arm does not turn Check that the rack is fully on its rails and not sitting on the arm. Also make sure no utensil dropped through the rack.
Rack sticks at the tub lip Clean hardened scale or food off the lip where the wheels transition from tub to door. A vinegar-soaked sponge works well.
Care Tips After the Repair
- Spin the wheels occasionally when the rack is out and replace any that begin to wobble.
- Avoid resting your weight or heavy cookware on the extended rack; that force splits wheel hubs.
- Keep the tub lip and door gasket clean so the wheels roll rather than drag.
- Check the rack wire coating for chips and touch up bare spots to prevent rust near the wheels.
- Use a dishwasher cleaner every few months to limit mineral scale on plastic parts.
Compatible Models (Sample)
This part is listed for 739 Whirlpool models in our fitment data. Always confirm your exact model number on the appliance's rating plate.
Repair Difficulty and Time
Difficulty: Easy. Typical time: 10 to 20 minutes.
Frequently Asked Questions
Is WP99002780 the same as the upper rack wheel?
No. This is the lower wheel assembly. The upper rack uses a wheel that rides inside a rail and mounts differently, so order the correct one for the rack you are fixing.
Do I need any tools to install WP99002780?
Only a flat screwdriver to release the old wheel. The new assembly presses on by hand. Gloves are recommended because rack wire can be sharp.
Can I replace just the one broken wheel?
You can, but if the other wheels are the same age they are probably worn as well. A single new wheel next to flattened ones still leaves the rack tilted.
Which dishwashers use this lower wheel?
It is listed for many Whirlpool-built Maytag and Amana models, including MDB4650AWW, MDB7755AWS, and DWU9906BAE. Confirm your model number on the door edge label before ordering.
Final Checklist
- Dishwasher cool, door open, lower rack removed
- Every wheel spin-tested and worn ones identified
- Old wheel assemblies pried off without bending the wire
- Mounting points wiped clean of scale
- WP99002780 pressed on until the retainer clicked
- Rack reinstalled level and rolling freely on the tub rails
- Lower spray arm spins freely with the rack in place
- Short rinse cycle run without scraping noises