The Collaborative International Dictionary of English v.0.48:

Overhaul \O`ver*haul"\, v. t. [imp. & p. p. Overhauled; p. pr.
   & vb. n. Overhauling.]
   1. To haul or drag over; hence, to turn over for examination;
      to inspect; to examine thoroughly with a view to
      corrections or repairs.
      [1913 Webster]

   2. (Naut.) To gain upon in a chase; to overtake.
      [1913 Webster]

   3. To repair thoroughly; to make repairs on; -- usually
      implying major repairs and perhaps modifying improvements.
      [PJC]

   To overhaul a tackle, to pull on the leading parts so as to
      separate the blocks.

   To overhaul running rigging, to keep it clear, and see that
      no hitch occurs.
      [1913 Webster] Overhaul

The Collaborative International Dictionary of English v.0.48:

Overhaul \O"ver*haul`\, Overhauling \O`ver*haul"ing\, n.
   1. A strict examination with a view to correction or repairs.
      [1913 Webster]

   2. A major repair or a revision for the purpose of
      improvement.
      [PJC]

WordNet (r) 3.0 (2006):

overhaul
    n 1: periodic maintenance on a car or machine; "it was time for
         an overhaul on the tractor" [syn: overhaul, inspection
         and repair, service]
    2: the act of improving by renewing and restoring; "they are
       pursuing a general program of renovation to the entire
       property"; "a major overhal of the healthcare system was
       proposed" [syn: renovation, redevelopment, overhaul]
    v 1: travel past; "The sports car passed all the trucks" [syn:
         pass, overtake, overhaul]
    2: make repairs, renovations, revisions or adjustments to; "You
       should overhaul your car engine"; "overhaul the health care
       system" [syn: overhaul, modernize, modernise]

Moby Thesaurus II by Grady Ward, 1.0:

119 Moby Thesaurus words for "overhaul":
   adjust, adjustment, amends, audit, autopsy, balance,
   balance the books, canvass, catch up with, check, check out,
   check over, check up on, cobble, come up to, come up with,
   commission, compensation, condition, correction, darn, demonstrate,
   do up, doctor, double-check, examination, examine, fix, fix up,
   fixing, gain on, gain upon, get ahead of, give an examination,
   go over, inspect, inspect the books, inspection, inventory, lap,
   leave behind, leave standing, look at, look over, making right,
   mend, mending, monitor, observe, outdistance, outpace, outrun,
   outsail, outstrip, overhauling, overlook, overtake, pass,
   pass over, pass under review, patch, patch up, peer at,
   perlustration, perusal, peruse, pore over, postmortem, prove,
   put in commission, put in order, put in repair, put in shape,
   quality control, ready, rebuild, rebuilding, recap, recompense,
   recondition, reconditioning, reconstruct, rectification, redress,
   refurbish, remedy, renovate, renovation, repair, repairing,
   reparation, restore, retread, revamp, review, run over,
   run-through, satisfaction, scan, scrutinize, scrutiny, service,
   set an examination, set to rights, sew up, size, size up, study,
   survey, take, take account of, take stock, take stock of,
   take the measure, tinker, tinker up, troubleshooting, verify,
   visitation