Clutch master cylinder and gear grinding sound

I have a 98 v6, I tried adjusting the plunger length on the master cylinder. It drove for about a day, then when I went to start it after work there was no clutch at all. just pedal to the floor. I pulled out the pin in the pedal, ( there was a little bit of fluid at the fire wall) spun it around and stuck it back in and it was working. So I am thinking I need a new master cylinder, thing is when I bought the truck, it was supposedly replaced. Reason I started to adjust it in the first place was there is a faint gear grinding sound around 1300rpms in second gear. And at times you can hear a "ping" like metal clanking when you put it in reverse. what is the best master cylinder? can it be anything else? thanks

 

The grinding and metal "ping" sounds when in gear is a bit scary and I'm assuming has nothing to do with the hydraulics. Others who are wiser than me can chime in.

As for best master cylinder, you'll get a lot of answers... I just went with OEM. It lasted me 170,000 ish miles on my 1998, figured might as well go that route again.

Aisin is the manufacturer of OEM parts so if you can find them cheaper online somewhere you should be good to go.