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Parts for GE TBX18DAXGRAA Refrigerator - AppliancePartsPros.com

Take a look at the tray assembly item 751 in section 06.

[COLOR="Blue"]I wondered if I could just seal the crack somehow, since the rest of fridge works great. I wasn't sure if the drain pan was plastic (glue?) or metal (special duct tape?),[/COLOR]
Trying to glue plastic is a hit and miss type of thing as you need to know what type of plastic is is.
I have used the foil glue backed duct tape but never in a situation where I needed a water type seal so cannot say if it would work.

[COLOR="Blue"] or where it is, really. (I was thinking it slid out the front, but no.)[/COLOR]
It is part of the actual body of the unit so even if you could get it you probably would need a pro to replace it.

Perhaps a jiggery pokery fix will work for you.
Remove the front kick plat and rear cover.
Clean out the pan there is probably a lot of dust and water scale in it.

1. See where the drain line drips into the pan.
Then see if you can find a metal pan (cake pan etc.) that will fit in that area.
Get as large a one as will fit.
Do not get one that is too deep as you need room above it for air flow so the water can evaporate.

2. Get some heavy duty tin foil and line the existing drip tray with it.
Just be sure that there are no holes in the corners etc. Once you get it lined you can cut off the excess. I like to double up the tin foil for extra protection.

[COLOR="Blue"] the part on the right if I'm facing the back, where a long pipe comes down from the center back?[/COLOR]
I am not 100% sure but I think so.
[COLOR="Blue"]
That's the same area that's near the fan, which I assume evaporates the water?[/COLOR]
Yes the fan helps evaporate the water and remove the moisture from un der the unit.