: On some 3000 and 4000 Product Families, the tag may be located on the driver's side (left side) near the bottom oil pan rail. Legacy and Off-Highway Models
Typically located on the passenger side, near the low-to-reverse clutch housing. Visual Identification
Using an ensures you get the exact specifications for your specific unit. This comprehensive guide covers how to find your serial number, how to decode it, and how to use it to keep your equipment running smoothly. Why the Serial Number Matters Allison Transmission Serial Number Lookup
For older cycling series (like the AT545, MT643) or massive off-highway hauling units:
"Need help identifying my Allison transmission — found this ID plate but not sure how to decode it. S/N: [paste full serial]. Truck: [year/make/model], VIN: [last 8 digits]. Any guidance on model family and compatible parts would be appreciated!" : On some 3000 and 4000 Product Families,
The seller had claimed a recent factory rebuild. But the serial number’s history showed something else. The last authorized software update was logged in 2020, and the transmission was still running the original OEM calibration from the truck’s first owner—a refuse fleet in Nevada. There was no record of a factory-certified rebuild, no updated calibration, no warranty transfer.
Do you have the 10-digit serial number, and are you trying to identify the correct fluid type, a replacement part, or the build date of the transmission? This comprehensive guide covers how to find your
Look on the passenger side of the transmission housing. It is often positioned on the lower rear face of the rear housing.
: By entering the serial number, users can access "historical build data," which includes the assembly part number and detailed configuration details. Warranty Status Check
Using the exact serial number prevents costly ordering mistakes. A visual inspection of the transmission is rarely enough because identical-looking models often feature different internal gear ratios, valve bodies, or torque converters.