I've never had any issues with a garbage disposal in our many houses we lived. This new house we custom built and moved in 2013, so the disposal is dated Sept. 2013 on the serial number.
Yesterday my cabinet under the sink had water after running my dishwasher. The water was coming out of the hole in the very bottom of the unit, and luckily I had a catchall bin underneath that caught most of the water.
All my research on this issues says just buy a new one if this is the case, that there is corrosion inside that can't be repaired. The warranty was for 2 years, so I have no recourse but get a new Insinkerator, for $99 or so. And then you are talking about paying for someone to install it for you.
I am disappointed the product failed after just 4 years. I am skeptical to replace with a same product. There will be more searching to find a reliable product instead of Insinkerator. I've never had this brand before and I don't think I'll stay with this brand. It has issues.