Guide
Repair, recondition or exchange unit: which gearbox route to take
Updated
Three different jobs get called gearbox repair. Knowing which one you are buying is most of the battle when comparing quotes.
The three routes
- Repair
- Fix what failed and put it back together. Cheapest headline price, shortest workshop time. The risk is that adjacent components already part-worn are reused, so a second failure can follow.
- Recondition (rebuild)
- Strip to component level, renew all wear parts whether or not they have failed, machine what needs machining, rebuild to specification and test. Higher price, longer in the shop, and the route that gives a meaningful warranty.
- Exchange unit
- A reconditioned unit off the shelf swapped for yours, with your old unit going back as the core. Fastest by a long way where one exists, priced as a unit rather than as labour, and normally with a surcharge if the core is not returnable.
- Remanufacture
- A fourth word some suppliers use, and the strictest. Gearbox remanufacture to BSI's standard for the process, BS 8887-220, turns a used unit into an as-new one with at least the performance and warranty of a comparable new replacement (BSI: BS 8887-220). Ask a supplier using the word whether they work to it and what warranty follows.
How they compare
| Repair | Recondition | Exchange unit | |
|---|---|---|---|
| Headline price | Lowest | Highest of the three in most cases | Fixed and known up front |
| Downtime | Moderate | Longest | Shortest |
| Price certainty before strip | Poor | Poor until stripped, then firm | Good, it is a unit price |
| Typical warranty | Narrow, often on the parts fitted | Broadest, on the rebuilt unit | On the exchange unit |
| Risk of repeat failure | Highest, worn parts reused | Lowest | Low, but you get an unfamiliar unit |
| Availability | Always | Always | Only where a rebuilt unit exists for your model |
Choosing
- Work out the cost of downtime first. If a day down costs more than the difference between routes, the fast route is the cheap route.
- Ask what the strip found before choosing. If the case and shafts are sound and only bearings have gone, a repair is reasonable. If housings are worn or gears are pitted, a repair is a false economy.
- Compare warranties properly. Length, what is covered, and whether it covers labour and removal or only parts. A twelve-month warranty on parts only is a different product from twelve months on the unit.
- Check the core terms on exchange. What condition your old unit must be in to avoid a surcharge, and how long you have to return it.
- Ask about the same failure recurring. If a bearing failed because of misalignment or contaminated oil, fixing the gearbox without fixing the cause buys you the same job again.
On vehicles, an exchange gearbox is often the standard answer for common models and a rebuild is the only answer for rare ones. On industrial drives it depends entirely on whether anybody stocks a rebuilt unit for your maker and ratio. See industrial gearbox repair and car and van gearboxes.