Originally Posted by benchmarkman
I really don't want to replace both at once because if I break something I don't want to have to figure out if its the dishwasher or garbage disposal I messed up. It would just be simplier to troubleshoot. I also don't want to spend the money right now. I like doing things in steps.
I understand the money concern, but unless you love working in cramped little spaces on a regular basis, this job is MUCH easier if you tackle both at same time. There is no way that you will be confused as to which is a causing a problem, if you have one. And if anything, your old existing disposal may be gummed up with grease or God knows what, and this WILL cause your spanking brand new dishwasher to have problems. The funny thing about most DIY plumbing is that almost anytime you touch one thing, it seems to set off a chain reaction, causing problems you didn't have before. do it all at once (if the budget allows) and save yourself the headache and backache and having to crawl back under the sink any time soon.
You said you like to do things in steps, but I think the more logical 1st step would be the disposal, since this is a major component of your sink drain. Personally, and speaking from experience, if I were in your shoes I'd wait until I could afford the disposal and do it all at once.
Good luck whatever you decide