Cotta recently repaired this High-Speed Gearbox Model SN1939-1 which has been in use for almost 14 years by a leading aerospace manufacturer of jet engines and related components. Our SN1939-1 gearbox is used to test production parts, such as engine-related components, at their manufacturing facility. During routine preventative maintenance, our customer noticed the gearbox had about a “tablespoon of metal debris” that collected on a magnet at the bottom of the gearbox. From our inspection here at Cotta, we found one bearing wasn’t spinning freely on the high-speed shaft – which we discovered also had a small chip in the shaft. Our Genuine Cotta Repair Service begins with a thorough inspection, cleaning and complete evaluation and then, after our diagnosis, only Genuine Cotta Parts are used as replacements during our reassembly process.

Model Series SN1939 High-Speed Gearbox Specifications:

  • Nominal Power of 600 hp
  • Max Output Speed of 30,000 rpm
  • Ratio Range up to 14.40 overspeed
  • Max Accel / Decel Rate of 2,000 rpm/sec at output
  • Approximate Weight of 1,600 lbs.

Model SN1939 is a foot-mounted, two-stage increasing, two output, high-speed gearbox that is designed for test stand use. This model has a stub input shaft and two aerospace output pads typically AND20006. Both output pads have the same direction of rotation and the same ratio. There is a special design option to have a different ratio on each output. Contact Cotta engineering for information on per head power capability. For more information about Cotta SN1939 and other high-speed gearboxes in our line, visit our High-Speed Gearboxes Page.


Cotta Model GR16E is a single-stage reduction gearbox designed for direct mounting to industrial engines via an SAE flange and driven in standard engine rotation (CW facing input shaft). This unit incorporates an idler shaft to provide output rotation same as input. Our speed reducers match the optimum engine speed to the optimum driven equipment speed, allowing your engine and load to both operate at ideal efficiency.

Typical uses include pumps, dredges, compressors, crushers, drills and high-performance machinery for oil & gas, construction, mining, and other industrial applications. Our heavy-duty gearboxes are designed for use with diesel engines, electric motors, PTO’s, and other prime movers. This particular unit here is a replacement GR16E401-1 Speed Reducer which will be used in the forestry market on a Morbark Tub Grinder in New Hampshire to chip limbs and branches. Cotta has supplied replacement gearbox units as well as service parts for many years for Morbark Tub Grinders worldwide.

Model GR16E Speed Reducer Specifications:

  • Max Input Torque of 1650 lb-ft.
  • Max Input Speed of 2200 RPM or as otherwise limited by input clutch or coupling
  • Ratio Range of 1.50 to 3.0
  • Integral foot mounts and integral lube pump supplied
  • Approximate weight of 1,500 lbs.

For more information about Cotta GR16E and our other speed reducers, visit the Speed Reducers Page.