One of the joys of owning a classic car is enjoying the analog engineering and aesthetics of the particular decade for which it was designed. 

When our classic Mercedes were initially sold, they came with a paper data card. The vast majority of these data cards have been lost to the river of time, and models before 1981 did not have their data digitally recorded by Mercedes-Benz. This article is a basic guide to finding the various codes on your vehicle to help you know exactly what you have in your car, which will allow you to be a more informed owner, making your parts shopping experience that much easier!

Where is my Vehicle Identification Number (VIN)?

Generally on a Mercedes after 1961, the VIN can be found a plate on the driver's door jamb. This is the most reliable location to check:

Some chassis have the VIN stamped into the firewall:

Some chassis have an additional VIN plate on the driver's side A pillar, which can be viewed through the windshield:

Models before 1961 are a bit trickier and were a tad less consistent in their placement of the VIN. Additionally, the VINs are 12 or 13 characters, not 14. Check out the diagram of plate placement on a W121 190SL!


The VIN is NOT located on the chassis info plate located near the hood latch on many models. This plate has very little relevant information on it. (Coming soon: how to de-code the numbers on your Mercedes).

Where is my engine code?

The engine code is a 14 digit string of numbers etched (not cast) into the engine block, just below the head. The numbers are about 1 centimeter in height. Be prepared to do some cleaning and make sure you have a strong flashlight!

On inline motors, this number located on the non-manifold side of the engine (USA/Germany Driver's side) as seen below:

On V8 engines, the code is behind the left cylinder head, facing upward. (Left means USA/Germany Driver's side).

Where is my transmission code?

This is a very important one, as it is not uncommon for a transmission to have been replaced since the car left the factory.
On automatic transmissions after the mid-70s, it is not to hard to find your six digit transmission code (which you will need to purchase parts from MBZ Parts). It is located on the right hand side of the transmission, at the seam of the oil pan. The 6-digit transmission code will always start with a 7.

Some automatic transmissions from the early-mid 70s will not have the transmission code stamped here— only the 10 digit part number. In this case, you will need to bring that 10 digit part number to us and we can decode it using our software. (see below)

Most manual transmissions, and Early automatic transmissions from the 1960s had different (and less consistent) systems. This is currently beyond the scope of this article!

Where is the gear ratio on my differential?

Beginning in the late 60s with the W114/W115 chassis and the introduction of CV joints, the differential ratio was stamped on a a corner tab of the differential as shown in the photo below. The last three digits on the tab are generally the gear ratio (for example, 3.69).

On 1960s and early 1970s chassis with the rigid differential-and-axle assembly, the ratio is stamped on the left side of the differential housing forward of the axles.