Solutions in Motion™

    Gearbox Repair: What To Do If Your Gearbox Breaks Down

    Posted by Troy Branham on Mar 5 ,2019

    gearbox repairWear and tear is a fact of life for machinery operating in industrial settings that feature high temperatures, high speeds, outdoor dirt, or harsh washdowns. Even the highest quality components eventually break down. Right angle gearboxes are generally low-maintenance, but if something goes wrong, how can you tell if you’re looking at gearbox repair versus replacement?

    The sooner you detect emerging problems, the better your chances of a less costly repair instead of an untimely, expensive gearbox failure. Developing problems can also push gearbox components out of spec, which weakens performance and speeds further damage. Here are some signs to look for and steps you can take to troubleshoot gearbox problems.


    This is the most common industrial gearbox problem. It is often caused by excessive internal friction, when work gears or bearings become misaligned or are improperly lubricated. Signs of overheating include:

    • The gearbox is hot. Don’t touch it! Spray a bit of water on the housing or shaft to see if it “sizzles” and evaporates right away.
    • Discolored or peeled paint on the housing.
    • Melted plastic components (if any).
    • Discolored lubricating grease (or inadequate fluid level).


    Damaged seals or gaskets can allow lubricating grease to leak, reducing gearbox efficiency and eventually damaging the bearings and causing premature gearbox failure. If the shaft seals are broken, water and other contaminants can get inside the gearbox.


    Both vibration and improper mounting can cause components to become misaligned (as can wear, over time). Mounting may invite problems because if the gearbox is not properly oriented, the possibility of contamination increases. Even tiny particulates can damage bearings. If gears are out of alignment, the teeth will show signs of pitting at one end.

    Repeated transient thermal expansion that occurs at start-up can also cause misalignment, as can external heat expansion due to the gearbox being located too close to a high heat source.


    Gearboxes may not be silent as they’re working, but excessive noise indicates something is wrong. Do you hear squeaking or rattling sounds? Instead of meshing smoothly with one another, the gear parts are out of sync, in effect “banging” against each other. Replace malfunctioning parts right away to avoid more extensive gearbox repair.

    Unexpected Loads

    Right angle gearboxes are designed to meet certain specs under certain loads. Any unexpected force or torque can damage the gears or cause bearings to fail.

    Installation note about Shaft Support: Shafting should be supported on all sides of gearbox
    with external bearing blocks. The internal gearbox bearings are designed to handle the internal
    loads and are not suitable to support additional, external radial or thrust loads. Failure to
    support external loads will reduce the gearbox efficiency and service life.

    Prevention is the most affordable approach

    The kinder you are to your hard-working gearboxes, the longer they will last and perform their best work. Right angle gearboxes are quite common because of their versatility in industrial applications. And, while they do not require much in the way of preventive maintenance, they do need some. The time you spend now can keep operations running smoothly and save you both time and money later on.

    • Regular inspection can uncover problems that lead to damaged seals as well as internal bearings, bolts, and so on. Look for grease leakage, and look for any signs of wear on gears.
    • Double-check alignment.
    • Check for signs of heat buildup.
    • Regularly clean the gearbox, to help prevent possible contamination. Never use solvents to clean the exterior or any internal parts. Make sure the gearbox is properly lubricated.

    Insert-A-Shaft gearboxes are pre-lubricated and ready for service. For light and moderate duty
    applications, they may be considered lubed for life and no further service is required.

    For continuous and severe duty use, periodic maintenance may be required. It is
    recommended to purge grease and re-lubricate every 1,500 hrs of service.

    For standard IAS models, lubricate with Magnalube-G® NLGI Grade 2 grease. For Food Grade
    application, use ACCROLUBE®-FG grease

    For CRL models, lubricate with Lubriplate® 1500 Grade 00 grease. For Food Grade applications
    use Lubriplate®, FGL-00 grease.

    When lubricating remove the lower most port plug and inject new grease into zerk fitting in
    upper most port purging old grease out lower port. Re-install port plug.

    Lubrication amounts: 25 series = 1 oz (30ml), 20 series = .67 oz (20ml), 15 and 10 series = .50 oz

    Note: Overfilling may result in leakage, excessive heat and reduced service life.

    Things Go Wrong

    If your gearbox breaks down despite your best efforts, give us a call. We can help you figure out the cause, if need be, and help you get back in action as swiftly as possible, whether you need gearbox repair or precisely the right replacement.

    Right Angle Gearbox Maintenance & Repair Guides

    Topics: Right Angle Gearbox