Suzuki DF25/DF30 Four Stroke Service Manual, Page 238Get this manual
10-14 LOWER UNIT
Make sure that all parts used in assembly are clean and lubricated After assembly, check parts for tightness and smoothness of operation Before final assembly, be absolutely certain that all gear contact, shim adjustments and tolerances are correctFailure to correctly adjust these areas will result in lower unit damage(See the "GEARS SHIMMING AND ADJUSTMENT" section on page 10-23)
PINION GEAR Place pinion gear and pinion back-up shim in gearcase
FORWARD GEAR Place the forward gear bearing and back-up shim in position, then install forward gear 199000-22540Suzuki Outboard Motor Gear Oil