Documents that speak about updates to parts and service procedures tend to be internal documents. I don't think you will be able to research this yourself. Besides, I don't think it will be helpful for you for the purpose that you want it, which I am guessing is to make someone pay for your repair instead of yourself. The mere presence of an updated part doesn't mean the bad one was defective, nor does it obligate a company to replace it.
Here is a sample of a service bulletin: "An updated widget kit is now available. Use it on the following models..."
It doesn't say "An updated widget kit is now available, because we designed the first one poorly, and there is a possibility of fire if you don't install it." I am talking about normal service and parts documents, not recalls here.
I would have to agree with the last writer, that going to a smaller sales/service outlet, and speaking to the parts counter person, will afford you the personal and knowledgable attention that you are seeking. While that person won't have documents relating to Sears, he will know things about your appliance because all Sears appliances are made by other manufacturers.
In your case, if you have a front load washer made by Frigidaire, then there is an updated shock kit that is available. If you are handy with tools, you should be able to install this yourself.