First off... I've got to agree with the other posts, that some time in the TMs is going to be a very big benefit. Personally (everybody picks up things differently), I found the parts TMs to be a valuable resource to figure out how the inside's work, and THEN the operator's TMs became much more clear.
The drum lock pin is just that, it's a pin that inserts into the drum. Pull it out (shallow notches) to release the drum, or push it in (deep notches) to engage and lock the drum. It is not stout, it is only to prevent the "spring" in the cable and gravity from the chain from allowing the drum to vibrate it's self loose.
The drum clutch (the outside winch "IN/OUT" lever is a two dog sliding collar type clutch. There are only two positions at which it will engage, 180 degrees apart. If the dogs are not lined up correctly, it won't move. From the original post, the reference to the locking plate for said lever, thankfully it sounds like it is in the freewheel position, otherwise imminent and immediate damage would have occurred....
These things are quite effective, but very clunky and cumbersome to master on the first time around. Being as it's already bound up and there is ZERO margin for error at this time, I'm going to highly recommend something here... After the shear pin is verified as present and correct, with the in-cab PTO control in neutral and the drum lock lever out (in the shallow grooves) stick a screwdriver through the universal joint at the winch input and manually rotate it until the drum clutch lever will allow the winch to be engaged. Use the same screwdriver (or prybar, it's pretty solid...) manually turn the driveshaft to forcibly unwind the cable to the point where it is free and tension is removed from the drum and cable.
Place the drum clutch back in the "out" position so the drum will (should) freewheel. Attach a car, truck, ATV, compact tractor, etc to the cable and gently pull it out a bit, twenty or thirty feet preferably.
Now, with a "moveable" load attached to the cable, the cable out far enough so that you can SEE what it's doing, and enough distance for a poorly timed panic reaction time to an unexpected event, re-engge the drum clutch, you can operate the winch as per the TMs until you become comfortable enough with it's operation to try "close querters maneuvering" such as now, with the cable already wedged.
Operating this winch is a two soldier job. There's no regulations in the civilian world, so they often get operated single handedly, but you NEED to be on top of your game. Practice first before it's truely needed, recruit soldier B if it's at all possible, and by all means keep that screwdriver handy so that when you're done, you can "park" the winch drum that last little distance (whatever you're comfortable with) to leave the cable "locked" so it doesn't unspool, WITHOUT having to wait for the crunch to tell you that you're out of cable and now pulling the chain through where it doesn't fit...
