Allison Transmission Serial Number Lookup _top_ -

: Denotes ratio coverage (0–3 for close ratio; 7–9 for deep ratio).

If a transmission was rebuilt by a third-party shop (not Allison certified), they may have swapped the housing but left the old data plate. Your serial number lookup will tell you the transmission is a 2005 model, but internally, it might have 2020 parts. In this case, trust the internal TCM data via DOC, not the plate. Allison Transmission Serial Number Lookup

If you have access to software (dealers/repair shops): : Denotes ratio coverage (0–3 for close ratio;