Upper Gear Sets GLM No. 22510 22512 22514 New! 22518 New! 22530

All GLM upper gear sets come with:
GLM #21544 (OEM #382212) Bearing
GLM #21545 (OEM #379585) Bearing
GLM #21547 (OEM #375761) Bearing

GLM is first in the marine industry to have all of the OMC upper housing gear ratios!
Different size engines require different gear ratios in the drive. The manufacturer changes these ratios with different gear sets. The gear ratio change is in the upper gear housing*. All 1973-1985 OMC upper gear housings are identical** except for the tooth count on the gears. Below is a chart showing the tooth count for the different size engines used with OMC sterndrives.

*All lower gear housing ratios are either 2.0:1 for the four-cylinder engines or 1.83:1 for the six and eight-cylinder engines.
**The original driven gears in 1973 and 1974 upper gear housings are not machined for a centering cone. All 1975 and newer driven gears and all GLM replacement driven gears are machined for a centering cone. A new drive shaft with shorter splines and a centering cone must be installed when replacing the original (non-centering cone) driven gear.