Operation CHARM: Car repair manuals for everyone.

Transmission Identification

Transmission ID:




Transmission Identification Label: 3T40


The 3T40 transmission has several variations of electronic control system types. Refer to transmission name plate for specific two letter model and third letter, transmission identification reference. See "Automatic Transmission 3T40 Wiring Diagram" under "Computers and Control Systems"


Automatic Transmissions:
MD9 [1] 3T40 Models
Transmission Control System [2] TCC and computer feedback.






[1] Regular Production Option (RPO) is the Model code stamped on the transmission identification label and the RPO label. (Located on the rear trunk lid.)

[2] Torque Converter Clutch (TCC) is electronic torque converter lockup.


Hydramatic 3T40 models used: BUC, BYC, CHC, KDC, KKC, KNC, LFC, LJC, LLC, AJC, AKC, AZC, LUC, LZC, PDC, PJC, PNC, PRC, PTC, PXC, & TRC.