We have a Maytag MZD2766GES side by side refrigerator. Stainless steel
front, ice/water dispenser in the freezer door, filter. Looks good, came
with the house, don't know the age.

Works well, but recently a sheet of ice has been forming on the bottom of
the freezer. The freezer bottom slopes from back to front, and the ice seems
to start at the back and each day extends nearer the front. After 3 days it
is almost to the door.

Initial guess is that the defrost drain tube might be clogged, but I this
beast does not seem to have such a thing. There is nothing in the manual
about a drain or keeping it clean and I can't find anything on the internet.
There is no evaporation tray below the fridge and I can see anything in the
freezer compartment to disperse water. So when it defrosts, where does the
water go?

Any idea what might be causing the ice and how can it be fixed?

Hi,

Maytag MZD2766GES side by side refrigerator,
don't know the age

The serial # will help with that...
http://www.applianceaid.com/appliance_age.html

the ice seems to start at the back and each day
extends nearer the front. After 3 days it is almost to the door

Certainly sounds like the defrost drain is clogged or restricted.

Initial guess is that the defrost drain tube might be clogged, but
I this
beast does not seem to have such a thing

It does, behind the back wall in the freezer is where it starts.

http://www.applianceaid.com/frig_leaking.html
Some helps and tips.

There is no evaporation tray below the fridge

Yes there is...you can see a pic of it from below...
http://www.repairclinic.com/referral.asp?R=153&N=665946

jeff.
Appliance Repair Aid
http://www.applianceaid.com/