Essential tool needed for installing and replacing rear main bearing oil seal on GM Holden V6 3800 engines. Diameter: 3.7/8" (165mm) / Used when replacing the rear main oil seal which aligns the housing on Holden V6 3.8L engines.

The combo includes:

DM25-1219

GM / Holden rear Main Oil Seal Housing Aligner Set - Commodore 3.8L V6 

DM25-1227

GM GM/Holden V6 3800 Commodore rear main bearing oil seal installer