LG dryer DLE2101W stacked on LG washer. During start-up of washer's spin cycles, dryer produces a knock/rattle at lower left front corner. How do I get into the unit and fix this problem.

the hum is usually a bad motor? perhaps u hear what u think is a hum? the rattle can be due to bad bearings, for example transmission spin bearings, tub thrust washer bearing, loose belt or worn belt.

is that a top load or front load washer?

a loud noise comes when you forget to remove shipping bolts after installation or if the shocks are worn out it makes noise thirdly the bearings might be worn out if the washer is more than 6years old

see the possibles causes:
see the diagrams. God bless you
No power
test the fuse blown + c.breaker trip
Lid switch
test the lid switch for continuity with VOM
spin: see the diagram

Hello.
Noises are common when using a two-in-one washer and dryer, as clicking or whirring is part of the cleaning process during the transition to the next cleaning process. The GE Spacesaver washer and dryer combo uses a top-loading washer stacked beneath the front-loading dryer, and uses an agitator that makes noises throughout the spin cycle. Although whirring or clicking is normal, other noises or malfunction indicates a problem with the washer that requires minor troubleshooting. Professional repair is necessary if the washer continues to experience problems during the spin cycle, as there may be a problem with the washer's agitator.
1 Open the washer's door and check the balance of the load's clothes. Clothes that are unevenly distributed around the agitator cause excessive shaking and result in an imbalance during the spin cycle. Reduce the load's size by removing clothing if the washer's drum is overloaded.
2 Push "Start/Pause" to pause the spin cycle and turn the washer's cycle knob to the "Off" position. Turn the knob to "Spin Only" and press "Start/Pause" to reset the cycle.
3 Turn the wrench counterclockwise or clockwise around the unit's legs to adjust the appliance's balance. The legs are adjustable with the help of a wrench to ensure the unit does not shake while in use. An unleveled unit shakes as it spins, and causes excessive squealing or rattling as it attempts to dry the clothes.
4 Touch "Start/Pause" on the front of the washer's control panel and unplug the washer/dryer unit's power cord from the electric oultlet. Wait two minutes and plug the power cord back into the electric outlet. Push "Start/Pause" to resume the spin cycle.
Thanks.

Check the filter at the bottom left side of the washer. It could be plugged up with debris.
Hope this helps.

I had this issue when I first purchased my stackable washer.. Because it was still under warranty, I had someone check it out. Apparently when it was installed they forgot to take out the security clamp that secures the unit during delivery.. duh!!

Replace the timer, you can find the product name model and serial number on two place. Either the back panel or on the lid underneath. Please rate if this helped thank you

defective timer...a model # should be under the lid...or open dryer door and on front dryer panel right hand corner..onthejob

Mine is doing the same thing. I opened it up to see what was happening and it was the drive belt tension arm bumping around. Soon, the belt started slipping during the spin cycle. Now it won't spin and the belt starts to smolder from the friction of the drive motor. If you haven't checked your belt, that's a good place to start.