How to find and read your gearbox number

Most transmissions are built by a handful of manufacturers and fitted across dozens of badges. A Volvo, a Ford, a Peugeot and a Land Rover can all be running the same Aisin unit. On classic cars the picture is worse, because sixty years of owners have swapped boxes between models, fitted ribcase units to smoothcase cars and put five-speed conversions in almost everything.

Give us the number and we can be certain. Give us the registration alone and we’re guessing.

• Casting numbers. Raised numbers cast into the main case, usually on the side or the underside. These identify the casting, not always the exact specification, but they narrow it down considerably.
• Stamped pads. Many classic boxes have a flat machined pad with numbers struck into it. Clean it with a rag and some solvent. Sixty years of oil and road dirt hide these completely.
• Identification plates. Riveted alloy or steel tags, often on the bellhousing or the top cover. Frequently missing.
• The tell-tale details. On some families the case itself tells you what you have: ribbed versus smooth casing on A-series boxes, removable versus integral bellhousing on Ford Type E units, the shape of the tailhousing. Photograph the whole box and we can usually tell.

• VW Group three-letter code. A three-letter code identifying the gearbox, usually on a sticker in the service book and stamped or on a label on the unit itself. This is the single most useful piece of information on a VW, Audi, Škoda or SEAT.
• ZF identification. A label or plate on the sump or the side of the case carrying the unit type and a serial number.
• Ford tags. A metal tag on the case, or a barcode label, giving the transmission code and build data.
• The VIN. Not conclusive on its own, but combined with photographs it usually gets us there.

Photographs beat descriptions every time. Send us:

• The whole gearbox from three angles, in reasonable light
• Any casting numbers, stamped pads or plates, close up and in focus
• The vehicle registration or the VIN
• What the car is, and what the gearbox is doing

Email them or send them through the quote form. We’ll come back to you the same working day with an identification and, where we can, a price.

They’re hard to read because they’re shallow, oily and in shadow. Two things help: clean the pad properly with solvent, and light it from the side rather than straight on so the stamping casts a shadow. A phone torch held at an angle by someone else works better than the camera flash.

If you’re buying a gearbox rather than rebuilding your own, send us the seller’s photographs before you pay. We’ve seen a lot of people buy the wrong ratio, the wrong input shaft length or the wrong bellhousing arrangement, and a wrongly bought box is usually a total loss. It costs you nothing to ask.