legacycentral bbs

First, this is not from my car this is from my moms 98 altima, but I don't really visit any other car forums so I hope noone really minds :\. Anyway, it's been having some strang noises going on, first is when the clutch is depresed there is a almost popping noise about a second later, I checked the clutch fluid level at it was normal. It doesn't happen everytime it's depressed but only certain times, no real pattern to it. Second I was backing the car out today with the clutch depressed with the tranny in no gear(dont ask) and I heard a grinding noise, not really loud and it couldn't be felt either. The sound slowed down as I came to a stop and I didn't notice it when driving forward. She's been keeping fairly good maintenence of it so could this be one of things that'll get cleared up at the next service or is it soemthing that needs to be taken care of asap?