What gearbox is in my car? How to identify your automatic (ZF, Aisin, Mercedes)

The quickest way to find out what gearbox is in your car is the gearbox code or type number on the transmission itself, on a plate or sticker on the gearbox casing. If you cannot reach it, a dealer can look up the factory gearbox from your VIN, or a specialist can read the transmission control unit. Make, model and year only give a direction.

That last point is exactly where it goes wrong. The same model from the same year often left the factory with two or three different automatics, depending on the engine, the drive layout and the trim. And if the gearbox was ever replaced, there may be something quite different in the car from what the factory fitted. Below you will read where to find the code, why your registration number alone is not enough, and how to recognise the automatics we see most often in our workshop in Montfoort.

How to find out what gearbox is in your car

Work through these steps in this order and in most cases you will have your answer:

1. Look for the identification plate on the gearbox. The transmission casing carries a sticker, an etched plate or a stamped number with the gearbox type and serial number. This is the only source that tells you what is actually in the car now.
2. Check the vehicle data sticker. Many makes print the transmission code next to the engine code on a sticker in the boot, near the spare wheel well, or in the service book.
3. Have the factory data looked up from your VIN. A main dealer or specialist can see from your chassis number which gearbox was fitted at the factory. That is reliable, unless a different gearbox has been fitted since.
4. Have the gearbox read out. Professional diagnostic equipment reads the transmission control unit, which stores its identification. A simple fault code reader usually does not show this information.
5. Count the gears as support, not as proof. Five, six, seven or eight speeds rule out a lot, but several gearboxes share the same number. Use it to check, not to conclude.

Not sure whether you have a conventional automatic or a dual-clutch gearbox at all? If you drive a Volkswagen, Audi, SEAT or Škoda, start with which DSG gearbox do I have. For the bigger picture of the different types (manual, automatic, DSG, CVT), see our guide to gearbox types. And if you want to know how a conventional automatic with planetary gear sets and a torque converter actually works, read how an automatic gearbox works.

Can you find the gearbox by registration number?

Not completely. In the Netherlands, the RDW’s public vehicle check (kentekencheck) shows the registered vehicle data, but in our experience not the gearbox code or the transmission type number. Commercial registration lookup sites and parts finders, in the Netherlands as well as the UK “gearbox code by reg” tools, link your registration number to a parts catalogue and then show a list of possible gearboxes. That is a direction, not proof.

The problem is the step in between. A catalogue works with a version of the model, not with your specific car. If a second-hand gearbox from another model was fitted, or the factory switched versions halfway through the model year, the catalogue no longer matches. When you order oil or parts, that is not a detail. You often only notice the wrong oil months later, when the damage is already done.

Which automatic gearboxes are most common?

A handful of families covers a large part of the automatics in cars built over the past thirty years. ZF supplies longitudinal gearboxes for rear-wheel and four-wheel drive cars, Aisin and Aisin AW supply transverse gearboxes for front-wheel drive cars, and Mercedes builds its own 722 series. The overview below shows, per gearbox, where it is fitted and the complaints we typically see.

ZF 8HP and 8HP45

The ZF 8HP has become the standard automatic for cars with a longitudinal engine. ZF introduced it in 2008 in the BMW 7 Series (760Li), more than 15 million had been built by 2023, and more than twenty brands use it. The number in the name indicates the torque the gearbox is designed for: a ZF 8HP45 handles about 450 Nm, the 8HP70 about 700 Nm.

In our experience, complaints on this gearbox rarely come from weak gears. They are almost always about the fluid and what contaminated fluid does in the mechatronic unit. Friction material from the torque converter’s lock-up clutch ends up in the oil, the narrow valve bores in the valve body wear, oil pressure drops, and you get jolts or slipping. There is more about this family on our page about the ZF 8HP.

ZF 5HP19

The ZF 5HP19 is the five-speed automatic ZF introduced in the mid-1990s. If you see ZF5HP19 or 5HP19 on a parts list, be careful: there are several variants that are not interchangeable. There is a base version for rear-wheel drive BMWs (where BMW calls it A5S 325Z), the 5HP19FL for Audi and Volkswagen with front-wheel drive (known there as 01V), the 5HP19FLA for quattro and 4motion, and the 5HP19HL and HLA for Porsche.

These gearboxes are now twenty years old or more. What we find is rarely a design flaw and almost always age: fluid that was never changed, a torque converter at the end of its friction lining, and valve body wear that makes shift pressure drop.

Aisin TF-80SC

The Aisin TF-80SC is the six-speed transverse gearbox you find under a long list of front-wheel drive cars. Volvo calls it TF-80SC, Opel uses AF40-6, Ford AWF21 and Peugeot and Citroën AM6. Different names, essentially the same gearbox.

The typical picture: for the first few minutes after a cold start it shifts harshly or jerkily, and later in the day it is better. In our experience that usually points to wear in the bores in which the valves of the valve body move. Fluid then leaks past the valves and the shift pressure is no longer right. A second common thread is the torque converter, which leaves its friction material in the fluid and so contaminates the rest of the gearbox.

Aisin AW55-50SN and AW55-51SN

The AW55-50SN is the five-speed predecessor of the TF-80SC and sits transversely in front-wheel drive models. This Aisin AW gearbox also carries a different name depending on the make: AF23 and AF33-5 at GM and Opel, RE5F22A at Nissan. On parts lists you will see both AW55-50SN and AW55-51SN; they are closely related versions of the same design.

Complaints here usually start with slipping or irregular shifting, and in our workshop the cause is often in the valve body and the solenoids. Here too, contaminated fluid is the driving force.

Getrag 260

Watch out, because this is where people regularly go wrong: the Getrag 260 is not an automatic. It is a five-speed manual gearbox, used among others in BMW models such as the E28, E30 and E34. If you find that code on your gearbox, you know straight away that you do not need to look for it among the automatics.

What you do find on a gearbox like this is classic wear: synchro rings that wear out and bearing play that you hear as a hum that rises with road speed. We rebuild manual gearboxes too.

Mercedes 722.6 and 722.9

Mercedes uses its own type numbers. The 722.6 is the five-speed 5G-Tronic from 1996, which went into almost every model and, as NAG1, also appeared at Chrysler, Dodge, Jeep, Jaguar and SsangYong. The 722.9 is the seven-speed 7G-Tronic from 2003, the first seven-speed automatic used in a production passenger car. It started behind V8 engines and later went into many six-cylinder models.

Both gearboxes share a weak spot in our experience: the conductor plate, the electrical module inside that controls the solenoids. On the 722.6, oil also tends to leak through the electrical connector, out of the gearbox or along the wiring towards the control unit. If your car with a 722.9 jerks or goes into limp mode, the conductor plate and valve body are the first place to look.

Why it matters which automatic gearbox you have

The gearbox type decides three things you cannot simply choose yourself:

• The type and amount of fluid. Every gearbox has its own specification, and they are not interchangeable. A ZF 8HP needs a different fluid from an Aisin TF-80SC, and even within one family it differs per version. See gearbox oil types.
• What happens at a fluid service. One gearbox has a replaceable filter in the oil pan, another does not. Some need the level set at a specified temperature with the engine running, because otherwise you only reach part of the fluid or fill it wrongly. Read more in changing gearbox oil.
• What is technically possible after damage. On one gearbox a targeted repair of the valve body or the torque converter is realistic, on another a complete automatic gearbox rebuild makes more sense.

That is why we always ask for the gearbox type first, before anything is drained or ordered. If you do not know it, we determine it. We would rather spend a few minutes identifying the gearbox than order the wrong part on the strength of a catalogue.

Frequently asked questions about identifying your gearbox

How can I find out my transmission code?

Look for the plate or sticker on the gearbox casing first, then the vehicle data sticker in the boot or the service book. If neither works, a dealer can look up the factory gearbox from your VIN, or a specialist can read the transmission control unit. Only the plate on the gearbox itself shows what is in the car now.

What gearbox is in my car by VIN?

The VIN tells a main dealer or specialist which gearbox the car had when it left the factory. That is reliable for an original car. If the gearbox has ever been replaced, for example with a used unit from another model, the VIN data no longer match, so check the plate on the gearbox as well.

How do I find out what gearbox I have without lifting the car?

Start with the vehicle data sticker with the transmission code, often in the boot or the service book. If there is nothing there, a dealer or specialist can look up the factory data from your VIN or read the gearbox with diagnostic equipment. Only the plate on the gearbox itself shows what is really in the car.

Is the gearbox type in my car’s owner’s manual?

Usually not. Owner’s manuals explain how to use the automatic, not which type is fitted. Workshop documentation and the factory data on the VIN do give it. So do not spend too long searching the handbook; go straight to the sticker or the plate.

Can an OBD2 reader tell me what transmission I have?

Usually not. A basic OBD2 reader shows fault codes, which are something different from the gearbox code. The transmission’s identification is stored in its own control unit and needs professional diagnostic equipment to read. If you are looking for what a fault code means, see our overview of transmission fault codes.

Is a five-speed automatic less reliable than an eight-speed?

Not by definition. A five-speed gearbox such as the ZF 5HP19 or the 722.6 has a simpler layout; an eight-speed ZF 8HP shifts more smoothly and economically but has a more complex mechatronic unit. In both cases maintenance decides the lifespan more than the number of gears.

My automatic jerks. Does the gearbox type say anything about the cause?

Yes, it gives a direction. In our workshop, jerking after a cold start on an Aisin TF-80SC often points to the valve body, vibration at steady speed on a ZF 8HP to the torque converter lock-up, and limp mode on a 722.9 to the conductor plate. Only reading out and inspecting gives certainty. Find out what your symptom could mean.

What does an automatic gearbox rebuild cost?

That depends on the gearbox type, the damage and whether parts such as the torque converter or the mechatronic unit need to be included. We always start with a diagnosis. What drives the price is explained in automatic gearbox rebuild costs. Contact us for a price indication based on your registration number and complaint.

Not sure which automatic gearbox you have?

Send us your registration number. We determine the gearbox type, read the gearbox if needed and tell you which maintenance or repair belongs to it, with a price indication before we do anything. ATR Transmissies in Montfoort rebuilds automatic and manual gearboxes from makers such as ZF, Aisin, Aisin AW, Getrag and the Mercedes 722 series, for private drivers and for garages across the Netherlands.

Book your car in or send your question with your registration number. You can read more about how we work and the parts we make ourselves on our about ATR page (in Dutch).

For garages: not sure which gearbox a customer’s car has, or what is wrong with it? With ATR Remote we read the transmission remotely, so you know the gearbox type and the fault before you order parts or send the car on.