I have read posts saying that one of MB's features for the older models, was the possibility of shifting gears if one felt they needed to or for performance increase. What kind of damage could be created from doing this, and what RPM's should someone shift at?

I think I blew the modulator valve twice by shifting at too high of RPM's before, because I was trying to manually shift from 2 to 3 to D at about 2K-2.5K Rpm's. Is this possible or did I just really mess the clutch packings or transmission up really badly?

Thank you for ALL replys!!