Mercruiser Alpha One, R and MR Serial Numbers 6225577 THRU 0D469858
Insist on ONLY Original Factory Parts
Alpha Gen II, Alpha One, R, MR and MCI (and some older units) shift in the Lower Gear Housing Assembly.
The gear housing contains the lower gear set (pinion, forward & reverse gears), lower driveshaft, propshaft and shift clutch system.
The Water Pump Assembly is bolted down to the top of the lower gear housing and the impellar is driven by the lower drive shaft.
When rebuilding a Lower Gear Housing Assembly you need to be aware of a few things.
1. You need to I.D. the unit and make sure you know the correct ROTATION. 2. Thin shims are used behind the bearing races to get the proper gear and bearing clearances. 3.Special tools are required to rebuild or reseal a lower Gear Housing Assembly. 4. There are fine measurements which must be adhered to and you will need a good micrometer, small torque wrench (0-30 inch)
and standard torque wrench (20-150 lb). 5. You will need a Shop Manual. 6. You will need a clean workbench and working area. 7. You will need a parts washer and a hydraulic press. 8. You will need a way to pressure test the unit to 15 PSI when complete.
If you are not willing to invest in the tools required to build a Lower Gear Housing Housing then don't do it.
Even with the special tools building an upper drive is a challenge.
Every clearance, every bearing, every shim and every seal must be installed exactly to specification or the drive will fail.
We can review your failure.
Do a partial or complete disassembly (where possible), clean the parts and perform an inspection.
Take a few photos of the failed components and email them to us.
Our advice is free and it might save you money and aggravation.
Know your options.