I bought a maytag side by side in 2002; model # MSD2454GRQ, SN 18157432AL, REV # 18. Ice is forming at the bottom of the maytag freezer department. Overnight ice will form at about 1/8 inch and left has formed to 1/2 inch. What is the problem?

Type in the search engine on your computer Refrigerator Repair-Ice in the freezer- Whirlpool, Maytag, Kenmore
Do that and it should give you your answer.

Here is a video I hope this helps
APPLIANCE 911

Leaking Refrigerators

check for a bad/ loose/dirty gasket on the bottom side ofn the door. check your drainage line for clogging on the defrost system for back up

http://www.managemylife.com/mmh/owner_manuals/2127/MAYTAG-Bottom-Mount-Refrigerator-L0808124?brand_name_search=MFI2569VEQ10+MAYTAG

you probably have a stopped up draing behind freezer wall panel

You are having either a defrost problem combined with the defrost drain being frozen over. Need to unplug and remove the rear panel in back of freezer to examine exactly what is happening. Some models like yours have electronic vents that cole if the control becomes defective. . The other possibilities ar the
Adaptive Defrost part number 61005988
The defrost heater with defrost thermostat part number 61006199
Visit our site or click on your model number or part number. I will be here to assist you in your repair, Thanks Sea Breeze

Click Here=> PART NUMBER AND MODEL SEARCH FEATURE

OK, You need to unplug for a hour or so. Remove the rear panel in back of freezer to expose the evaporator coils. At the bottom of the evaporator there is a tray that catches the defrost water to take it through the back and down to the condensate tray located near compressor and condenser fan. Most likely you have ice or something trapped in that drain beginning in the freezer. I have heard some people turn the freezer temperatures so cold ice will form before the water can drain. If you still have problem contact me. If this helped vote or rate me. Thanks Sea Breeze

DEFROST THE FRIDGE BY SWITCHING IT OFF FOR 2 DAYS

Your drain is blocked causing the ice in the bottom of the freezer.
The drain is located about 7 inches up from the bottom rear of the freezer.
Just below the back freezer panel.
Turn the fridge OFF.
Remove the bottom bins.
Take a hair dryer and thaw the ice in the drain.
Pour 1/4 cup of bleach in the drain line.
Problem solved.

A bad freezer door seal causes condensation that freezes at the bottom of the unit. I realize you said the drip pan was full of ice, but if the drain is clogged, that will happen. If that unit has the pan at the very bottom, condensation can also contribute to this.