How to check a used gearbox before you buy

Before buying a used gearbox, do three things: match the gearbox code to your exact engine and not just the model, check the mileage and how the unit was removed, and confirm there is a clear return policy. A gearbox is a high-value part, so the checks matter, but a used unit from a properly run breaker is a sensible buy that saves you hundreds against a new or reconditioned box.

Here is exactly what to look at, in the order that matters.

Why is the gearbox code so important?

The same car can have several different gearboxes depending on the engine, the power output and whether it is manual, automatic or a twin-clutch. The model name is not enough. Every gearbox carries a code, stamped on the casing, that ties it to the right engine and ratios. Match that code, or give us your registration and we will identify the correct box, and you remove almost all the risk of buying one that will not bolt up or talk to your car.

What mileage and history should I ask for?

Ask for the mileage of the donor car and how the gearbox was removed. A box taken from a low-mileage car that was broken for a body or electrical fault is a very different prospect from one pulled because the transmission failed. A good breaker knows the donor's story and tells you. Lower mileage and a clean removal reason are what you want.

What can actually be checked on a removed gearbox?

More than people expect. The input shaft should turn smoothly with no grinding or notchiness. The casing should be free of cracks and heavy oil leaks. On a manual, the selector should move through its range. On an automatic or twin-clutch, the breaker should confirm the unit turned over and was not the reason the car was scrapped. If something cannot be confirmed off the car, an honest seller says so rather than guessing.

Does it come with what I need to fit it?

Check whether the box includes the bits you need: the mounting bracket, the bellhousing, and for automatics the torque converter. Clarify before you buy so the fit goes smoothly and you are not chasing a missing part afterwards. It is also worth budgeting for a new clutch on a manual and fresh oil on an automatic, since fitting those at the same time is cheap insurance.

What protects me if it is not right?

A return policy. At Partsworth every order is covered by our 30 day returns policy, so if the gearbox does not match or does not perform as described, you are covered. On a part this size, that safety net is what lets you buy used with confidence.

Where to start

Browse our engines and transmission parts, or the wider transmission and drivetrain collection. Every unit is inspected before it is listed, ships with free tracked UK delivery, and is backed by 30 day returns. Send us your registration and we will match the right gearbox to your car before you buy. Parts worth your trust.