[Messer]

I've been using a Saitek AV8R-01 joystick for about two years now and it's pretty good, but recently a very annoying problem appeared - one of my throttle controls (the left one) constantly falls down on its own when left at about 55% throttle or more. The problem got worse so I finally opened the stick and noticed that there was almost no grease(?) left on the throttle lever (the other one has a ton of it and is fine). I managed to scoop out just a little bit from the other joints so the throttle stick now slowly "plops" down, but the problem still persists (and I regularly get engine damage when I let it go in a dive).
Does anyone have any idea what is the stuff that's used to, er, lubricate(?) the joints so that the parts down move around on their own, and if it's commercially available?

Thanks!