I bought a 4000 pound winch, which is ample for my tracker, but I'm trying to figure out how much 4000 pounds of line pull is.  is it like a 4000 pound dead lift or how much would it be, better yet, how to convert it?

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 _\I=I___#4000_____  <---line pull direction over pulley
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The lifting weight is the pulling weight divided by your safety factor.
If you winch is designed for lifting you can easily pull twice as much as its rating, conversely a winch rated for pulling you would want to divide its rating by about three for lifting.
Regards Charlie
 

I think you would have to contact the manufacturer to get a definitive answer, there are an awful lot of variables. The maximum line pull is probably for a rolling load (ie not stuck!) on a firm level surface. The amount the winch can pull also depends on how much wire is left on the spool, the more wire left the greater the effective spool diameter and the more leverage. Even with an 8000 lb winch I have had to double the wire back and use a strop to pull up out of a deep mud hole. Some winch manufacturers state that their winches can not be used for dead lifting, I suspect this is to avoid them being sued when someone tries to dead lift the rated weight and the clutch breaks!

You ment to say the less wire on the spool the more power it has.

This is a good reference http://www.pirate4x4.com/tech/billavista/Recovery/

The key thing to keep in mind is the design factor.
You winch (pulling), winch cable and nylon straps have a design factor of 1.
Things like hoists (lifting) shackles, recovery hooks and chain usually have a design factor of 2 to 5.
Regards Charlie

You ment to say the less wire on the spool the more power it has.

My mistake  All the more reason to double back the cable.