I have a table lamp that had standard 75 watt bulb (I believe in a 3 way socket) which suddenly lowered to about a 40 W, or less without my touching the switch. I replaced it with a new 8.5 W 60 W = . The bulb appeared to flash and burn out, I did it twice with brand new bulbs, then quit before I wasted more bulbs! I have bought a new 3 way socket to replace in the lamp thinking it was a defective socket (I haven't done it yet as I've been pretty busy w/Christmas). Am I on the right track, or it another problem?
You may in fact be on the wrong track. When bulbs start blowing out, it's often a LOOSE NEUTRAL at your panel or the supply pole. Test the bulbs in another socket: if they are really blown, then look elsewhere for a serious issue.
3-way sockets have two energized contact points; 3-way bulbs also have two contact points to match those in the socket, because they have two filaments.
You need to by an LED bulb that specifically says it's compatible with 3-way sockets or replace the socket with a standard one (or use a traditional incandescent bulb).
It is possible that you have a socket that is in the process of failing. They typically are not precision quality items and experience a rather limited life. I doubt if you have damaged any bulbs. If the contact points seem to be loose in the socket or the switch seeming to make too much noise, it is suspect. Does the socket show signs of wear, any dark or burn marks. Is the socket old? All things that would point toward replacement of the socket.
Only 3-way bulbs can be properly matched to 3-way sockets.
A bit less critical; given the nature of mass production and the ancient technology in these types of sockets, these 3-way sockets, even brand new, can be erratic and preform inconsistently. I would say that something less than 60% perform flawlessly for a standard life of 10-years.