Genuine Volvo 780 Flywheel

Volvo 780 Flywheel Parts and Q&A

• Drive Plate
  6842012
  Q: How does the Flywheel process work for replacing a damaged ring gear on Volvo 780?

  A:

  The ring gear is engaged by the starter gear at the time of engine starting and any damage such as broken and chipped teeth or cracks must be detected and repaired, one of the causes being the starter. In vehicles with automatic transmission, the ring gear belongs to the flexplate and cannot be replaced, whereas in manual gearbox vehicles, the ring gear on the flywheel can be taken off and replaced (usually by heating it to 450F and handling it carefully). It is often easier to buy a complete flywheel and ring gear assembly than to make a replacement. To replace the ring gear, first disconnect the negative battery cable, raise and support the vehicle and remove the transmission. If there is a manual transmission, the clutch plate and disc should be removed followed by the bolts that attach the flywheel or ring gear to the crankshaft to remove flywheel or ring gear. Inspect the flywheel for any cracks, grooves or bluing and the ring gear for any burrs or worn teeth and replace if found. It is possible to remove the burrs with a mill file. For replacement of a ring gear, drill a hole between two cogs on the ring gear without damaging the flywheel, mount the flywheel in a vise with soft jaws and split the ring gear at the hole using a chisel. Wearing heavy gloves and using tongs for safety, heat the new ring gear to about 450 degrees Fahrenheit, then position the ring gear with the beveled side facing the flywheel, tapping the ring gear until it is flush with a brass drift. Allow it to cool in the air without any cooling processes which involve water or other fluids. Finally, install the flywheel, tighten the bolts in a crisscross manner to specification, reinstall the transmission, lower the vehicle and reconnect the negative battery cable.