“The gearbox creates a lot of vibration that can be easily felt on the floor”
“The second cat hoist has a separate sound, probably related to the input shaft or the first stage”
A customer from the Netherlands reported abnormal vibrations and strange noises in the gearbox. We inspected the transmission and made repairs. After a successful commissioning, we ship the gearbox back to the customer.
The description was partially confirmed at the scene, but there was no reason to take action. Vibration measurements and visual inspections of both gearboxes revealed no damage to the gears or bearings. Both cabinets are in good condition except for some minor leaks and imbalances on the sprockets.
Elevated oil levels in top-operating gearboxes are concerning. Complete immersion of the gear transmission creates resistance during mesh intervention, similar to the operation of an oil pump, which amplifies existing vibrations.
The most likely cause of the observed vibration is a combination of factors: sprocket imbalance and an increase in first-stage clamp frequency due to increased oil level. It can therefore be concluded that the vibrations are not the result of damage. This vibration is more prominent in the cabin. The structure of the cab may intensify relatively low-frequency vibrations.
No noise as described in the introduction to this document was found during the inspection. Neither vibration measurements nor visual inspection revealed any tooth or bearing damage. The case is in good condition except for some slight imbalance on the sprockets.
If the noise reappears and is a cause for concern, it is recommended to perform another vibration measurement, this time at no load, full speed, 1800 rpm.
We recommend:
- Make sure the gearbox is filled with the correct amount of oil, e.g. install a new oil level glass
- Ability to detect the development of damage on time every three months to perform vibration measurements
- Perform annual visual inspections (and increase vibration levels or detect error frequencies).
Post time: Oct-10-2023