Gearbox Repair and Overhaul


Initial Checking

Upon receipt at DCL premises, the gearbox is identified, booked, photographed and couplings or other attachments are removed. General condition of the drive is noted for our report, and end float and backlash are measured and recorded.

The gearbox is completely stripped, photographed, inspected and condition recorded. All shafts and gears are Fluorescent Magnetic Particle Crack checked. All bearing details are recorded, and compared with OEM supply. Upon client acceptance of DCL quotation the gearbox then moves to the next stage of refurbishment.

The Co-ordinate Measure Machine (CMM)

After a long service life, gearbox housings can be expected to be outside manufacturer's tolerances. For that reason, DCL Engineering conduct a complete dimensional check on the gearbox housing, using our Faro Arm CMM. This allows very high accuracy in measuring the following:

  • Concentricity and parallelism of bores
  • Ovality of bores
  • Horizontal and vertical positioning of bores
  • Mounting face flatness on all planes
  • Joint Face Flatness

This attention to detail is another of the ways that DCL Engineering is proud to say that "We do it better" than other so-called gearbox refurbishment companies.

Gear and Bearing Removal

DCL Engineering has several 400 tonne presses, plus 300 tonne and 100 tonne, as well as our portable hydraulic horizontal bearing puller. Removal of couplings, gears and bearings as well as any other attachments is made safer, quicker and easier by having all the right equipment in house.

Non-Destructive Testing

At DCL Engineering, we employ several methods of non-destructive testing of components. Gear housings are usually checked where required using a dye penetrant method of crack detection. Gears, keys and shafts undergo the more sophisticated method of Fluorescent Magnetic Particle checking, where a specially designed magnetic tool induces a magnetic field in the components. Fine metal particles are sprayed on, and the specific high powered fluorescent lamp will show any imperfections on the surface of the component being checked. For more detailed analysis, full x-rays can be done if required.

The benefit to you, as a customer, of this specialised checking procedure is that DCL Group has removed the possibility if inherent failure occurring if cracking was present and not detected. It is another example of the way that DCL Engineering goes that extra distance to give you the greatest chance of a long service life in your component once refurbished by us.

Bearing and Seal Journal Repair

Damaged shafts can be machined, metal sprayed and ground back to required diameter and surface finish. DCL can retain an OEM specification or improve hardness and surface finish to provide longer service life.

At DCL group, we don't simply opt for the simple run of the mill seal for your application. We spend the time to check the application with seal experts, and ensure that the brand, style, design and material used in the seal is the most appropriate for the application. Near enough just isn't good enough. With expert attention to the seal rubbing surface. DCL Group can assure you of the best possible chance of long service life without the dreaded oil leakage.

Shaft Checking

All shafts are checked for dimensional accuracy, concentricity, ovality and straightness before being reused. This, when added to the crack detection, means that as our customer, you can be confident that these components are not being reused unless they are at least up to, if not exceeding, OEM specification for that particular application.

Gearbox Reassembly

Gears and shafts are re-assembled with new bearings fitted, backlash and end float are checked against OEM and bearing manufacturers specifications, and the results are recorded for your report.

Tooth Contact Witness Mark

The actual witness marks are photographed and recorded in your report, so that you have full details of what was set before return to yourselves.

Laser Alignment

DCL Engineering wants the best possible outcome of our testing, and so testing begins on a machined base with laser alignment between motor to gearbox and gearbox to load. The DCL Engineering report covers alignment prior to testing which will also pick up 'soft foot' if present.

Unless our testing is done within the best possible environment regarding alignment, then the results may not mirror what you could expect once installed and operational on site. Again, DCL goes the extra way to give you, the customer, the best possible outcome of our testing. A copy of the finalised laser alignment data sheet is included in our report to you.

Oil Filtering

At DCL Engineering, we recognise that no matter how clean the environment, impurities will enter the gearbox once opened. For that reason, we have instigated an oil filtering procedure.

Oil is circulated and filtered through the kidney machine prior to the commencement of load testing and continued throughout the load test procedure. This way, DCL ensures that you receive back a gearbox with the least possible impurities within the reducer.

Gearbox Load Testing

At DCL Engineering, we recognise the need to test the refurbished gearbox prior to returning to site. Our preference is to do a partial load test on your drive, checking many different data points. Bearing temperatures are recorded automatically at predetermined time frames, and the test is conducted until well after the bearing temperatures have stabilised. The normal option is to also record Vibration Analysis data from relevant points, which go with the bearing temperatures into our comprehensive report. Other data can be recorded, including noise levels, should you as our customer feel the need for them in your report. The flexibility and willingness of DCL Engineering to co-operate with your requirements shows how we put you, the customer, first.

Painting and Preparation for Dispatch

The Scope of Work agreed upon prior to work starting could also include the final painting of the gearbox prior to dispatch. DCL Engineering Group offer many painting options using in-house paint systems, plus we can cater for other systems should you require them. Please ask for details should you have specification requirements for painting.

DCL Engineering will also prepare the goods for dispatch according to your requirements. Packaging, wrapping and different forms of protection can all be catered for by our Dispatch Division, even to the point of using our own DCL Engineering transport services. That way, full control of your job is maintained right through until final delivery.

Strip KZA 320 Gearbox
Strip KZA 320 Gearbox

Co-ordinate Measurement Machine
Co-ordinate Measurement

Gear Bearing Removal
Gear Bearing Removal

Non-Destructive Testing - Fluorescent Magnetic Particle Testing
Non-Destructive Testing -
Fluorescent Magnetic Particle

Seal diameter metal sprayed and finished ground to prevent 'necking'
Seal diameter metal sprayed and finished ground to prevent 'necking'

Backlash and End Float
Backlash and End Float

Tooth Contact Witness Mark
Tooth Contact Witness Mark

Laser Alignment
Laser Alignment

Load Testing
Load Testing