OMC 400/800 Rebuilt Upper Gearcase Pricing with Video


Rebuild your upper gearcase with old or new gear set

Last updated on 2/24/2023, 2:26:17 AM


  • Basic OMC 800 / Stringer upper unit repair $885.89
  • Includes all labor (see below), disassembly, inspecting and cleaning/refurbishing parts. A new ball gear, water pump assembly, bearings and seals are then installed in the re-assembly of the unit,
  • Followed by a full pressure test to ensure seals are holding in all areas of the repaired gear case.
  • If any additional parts need to be replaced, the replacement parts are added on top of the basic repair cost.
  • Typically, if the gears have failed in your unit, you’ll need a fully rebuilt unit. We re-manufacture and rebuild all of our OMC cases in house.
  • For more information on our rebuilt parts, see our replacement upper unit assembly page.

OMC 400/800 Rebuilt Upper Gearcase

Paint upper gearcase

After unit is repaired, a final pressure test is performed for 12 hours to ensure the case is holding pressure.

Basic repair cost $885.89 for low profile models (1973-1985). See above for what is included in basic repair cost.

High profile

Basic repair cost $945.89 for high profile models (1964-1972)

OMC 800 rebuilt outdrive upper case

New ball gear installed, with bearing retainer and steering re-installed. New exhaust seal and spring installed in upper.

Sandblast bearing housing

All parts are sandblasted, cleaned and inspected to determine if they will be re-useable or if they need to be replaced.

Shown here, the main bearing housing (P/N 27950 $125.15) is checked for any cracks or excessive scouring.


The bearing retainer, which holds the ball gear onto the upper housings (P/N 27960 $81.15) is checked for any damage or cracks.

The main housing, which holds the water pump housing is sandblasted and cleaned up. Typically, this part does not show any damage as it is held in with 4 large bolts and does not house any bearings.

The top cover (P/N 27860 $162.95), is inspected for any leaks. One common area where excessive wear may be found is on the inside perimeter of the cover, where scouring may be found which may prevent a proper seal in order to hold pressure.


The steering and bumper are also cleaned up, and the spurs on the teeth are checked for any damage to the ends along with the bushing it sits in.


Close up of worm shaft

Worm 2
The worm, which is connected to the steering shaft on the end, is checked for any irregularities in the lines of the shaft. This part typically does not have any damage and would not need to be replaced except in certain instances where it was damaged by a previous incorrect installation.
Loctite fill

Loctite retaining compound is used on certain areas of the housing to make sure components are sealed tight and can withstand added pressure.

Inspect 2

The inside of the housing, around the inside cylinder area where the water pump housing seats is checked for any cracks.

Polish housing
If the pinion bearing housing can be re-used, the outside top surface area is polished on a lathe to ensure proper installation.
Pinion housing

The entire bearing housing is sandblasted before re-installing into the housing.


The parts are sandblasted and inspected for pitting, chips or excessive wear.

Blast gear end

The end of the pinion shaft is inspected around the threaded area, and cleaned in in order to ensure the pinion nut can be installed to the proper torque specs.

Tap holes

The holes that secure the top cover are re-tapped to ensure the securing screws can be tightened to the correct torque.

sandblast steering area

The area that houses the steering and worm shaft are cleaned to ensure to steering can move easily.


After the upper is fully disassembled and the internal components are removed, the housing is sandblasted down to the aluminum inside and out.

Polish gearcase retainer area

Shown here, the section of the housing that holds the bearing housing for the ball and pinion is polished in order for the bearing housing (P/N 27960 $81.15) to install cleanly into the housing.

Clean up on lathe

The spacer shaft which holds the worm (which moves the steering shaft), is polished on a lathe.

Polish seal retainer area

The ball gear bearing retainer (P/N 27960 $80.15), is cleaned up and polished on the outside surface lip area so it seats evenly when installed into the housing.

Repair retainer

The inside of the retainer is repaired by machining on a lathe to remove any pitting or minor damage. If this part has any cracks it must be replaced.

680 Loctite in retainer

680 Loctite is applied to the inside area.

Install seal one

The first oil seal is then installed with 680 Loctite retaining compound.

Install seals

The second oil seal is then installed flush, ensure both seals along with the Loctite will hold pressure.

Primer Zinc Chromate retainer
The retainer is coated with zinc chromate primer after being cleaned.
Blast Swivel
Polish swivel
Pump drive shafts
Old stripped shaft
Pinion shaft
Worn old unit
21546 Pinion bearing
27820 Bushing
31173 Steering gasket
Polish upper housing