Which factors determine whether an accessory drive gearbox should be overhauled rather than replaced?

• A. Overall appearance and color
• B. Noise level during operation
• C. Gear wear, bearing clearance, tooth damage, leaks, and backlash; compare to OEM limits
• D. Warranty status

Answer: (C)

Determining whether to overhaul or replace hinges on the actual condition of the gearbox components measured against the manufacturer's stated limits. The most important factors are gear wear, bearing clearance, tooth damage, leaks, and backlash, all evaluated against OEM specifications. If these measurements and the overall condition are within limits and the unit can be refurbished to spec, an overhaul restores function without the expense and downtime of a full replacement. If any of these aspects exceed limits or show unrecoverable damage, replacement is the safer, more reliable choice.

Appearance, color, or noise level alone aren’t reliable indicators of internal condition, and warranty status isn’t a technical criterion for deciding overhaul versus replacement.