The big pedal on the right side, not the forward or reverse pedals, is the parking brake. That parking brake pedal operates a safety interlock that prevents the PTO (electric clutch) from engaging the mower deck when set. More than likely there is an adjustment for the switch or the switch is failing. Sometimes a piece of debris, a twig or such, gets stuck up there. There is a possibility that the "new" clutch is defective or out of adjustment. Did you buy real JD parts or aftermarket? What was the original problem that necessitated the new clutch and switch and battery.? I*f you can't "common sense" it by looking you'll need the technical manual for your X300 (and it costs $$$) or get your X300 to the JD dealer.

***"sometimes when trying to reengage the PTO or engage the transmission it will kill the engine"*** Sounds like it may be related to a safety interlock switch, or a relay that is part of the safety interlock circuitry. Is your PTO hydraulic, controlled by a solenoid valve? If that is the case, a defective solenoid valve might be overheating to the point of "going open" or even "shorting out" after it has been energized for the 20 to 30 minutes of operation. But, sometimes relays can act up when they are overloaded by too much current draw when they get old, or, if the device they are controlling develops too much resistance or "shorts out". When the engine "kills", will the engine crank right back up? or does it act like the battery is weak or dead?

In my opinion as an owner of a Freedom 42 deck, there is not a chance in h*** that you caused that blade to come off by hitting something. These decks have the blades positioned in one spot with a small lug, they do not rotate freely on the spindle like most blades. When bolted tight, they cannot be rotated on the shaft without breaking something metal. In addition, the special timing belt that runs between the two blades seems to break at the drop of a hat (ie: with only slight contact with an obstruction). If you timing belt is still connected between the two spindles, it is very unlikely you could have hit anything hard enough to damage blades. The only logical explanation for a dropped blade with no other mechanical damage is that the blade was not tight enough in the first place, the bolt dropped off and the blade just dropped straight down. Note that you cannot just buy Gator blades as suggested. These decks take very unusual blades that are virtually flat -no lifting edge along trailing side like most blades, and no space to allow such a blade to be fitted. The trade is that they do an outstanding job at the only thing that they were designed in tandem with the deck design to do - mulch. Also, if you find the old one, or buy new ones (2) be very careful how you install them. They are not two of the same blade -one rotates to the left and one rotates to the right, so the cutting edges are on opposite sides and you must put the correct blade on the correct side of the deck. Also, since they are flat, you can install them upside down, so that the cutting edge is on the back side of blade, not on the front where it meets the grass. I know the above in detail because when I got my Freedom (with JD LT160), the dealer had installed new blades both on the wrong sides and upside down. That caused the prior owner to just about throw away a nearly new machine because the cut was so poor :)) Details of the installation are in the manual. Anyway, press the dealer - this cannot be explained as operator error without some visable mechanical damage. Still a very good chance youwill find that blade in teh grass, and it just needs a new bolt and washer (both are stock, not a late fix).

Oh lordy, here we go yet again. Use the forum search facility at the bottom of the forum opening page and do a search for subject like "Hydrostat oil change, Hydrostat fluid change, Hydrostat transmission slipping. This is a perennial complaint and YES, the oil can be changed (no matter what the book or the dealer say). and YES, old, degraded oil will cause symptoms like this. Many are the hydrostatic transmissions still going strong that would otherwise have gone to the scrap yard but for an oil change, which is not that hard to do (you said you are handy, or know someone who is). :^)