The flywheel housing is more than just a part that holds the engine to the transmission. The housing also servers as the support bearing carrier for the bottom 2 gears of the 'drop gears'. The helical cut idler gear uses a thrust washer to control movement. When the trust is allowed to be excessive, the aluminum face of this housing will wear away and must be replaced. This Pre-Owned (USED) housing will work great on pre A+ engines (4 sync idler). Actual condition and appearance may vary from photo shown.