Date of Mfg. on Vin decal on drivers door jam.
Transmission serial on tag on passenger side of transmission.
2001-2003 and Mfg. dates prior to February 04 are LB7 transmission models. Even if truck has LLY engine.
2001 and 2002 have 3/4 threads on cooler fittings, 2003 and later have 7/8 threads.
Mfg. dates of February 04 and later begining with serial # Indianapolis 6310374684 & Baltimore 6320367833 have the late (LLY) style transmissions.

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