I've had this problem intermittently in the past, but it went away on its own. when I move the lever to shift to a smaller rear cog, nothing happens. there is no resistance. The lever moves freely, but nothing happens. If I keep at it, it eventually "catches" and I can shift pretty normally. There is a very slight amount of front-to-back play in the lever, and I find that if I push the lever slightly forward, it will catch and shift. It shifts into larger cogs with no problem. what could be going on. It is a dura ace shifter and it is about seven years old.