I think I remember answering a similar question before, but I can't
remember when or where it was asked.

Anyway, I believe the solution I offered was to deal with the excess
rope on the fixed side of the truck rather than on the tensioner end
of the rope. Try to get the rope on the tensioner side to be about
the length you want, and then if you don't have end access to what
you're hitching to on the fixed side (like a hook), then use a Midspan
Sheet Bend to close off a loop as shown in the second diagram on the
bottom of this page:

http://www.geocities.com/roo_two/midspan.html

(If you do have a hook, you can use a Pile Hitch or a loop on the
bight.)

Then on the tensioner side, use a Versatckle or some variant of your
choice to tighten things up:

http://www.geocities.com/roo_two/Versatackle.html

And then coil up or braid up the excess rope on the fixed side:

http://www.geocities.com/roo_two/ropestorage.html
http://www.geocities.com/roo_two/gasketcoil.html

Cheers,
roo