2003 Bombardier Outlander 400 Factory Service Manual, Page 116Get this manual
Subsection 08
Section 03 ENGINE (LUBRICATION SYSTEM)
R400motr128B
1Oil pump outer rotor surface 2Dial indicator
Difference between pump housing and outer rotor should not exceed 0.1 mm (.004 in)If so, replace replace the complete oil pump assemblyNOTE: When the axial clearance of the oil pump shaft assembly increases, the oil pressure decreasesCheck the inside of oil pump housing and its cover for scoring or other damagesIf so, change the complete oil pump assembly