The J-Series platform currently uses three different bellhousing designs. Generation 2 and Generation 3 bellhousings feature a noticeably rounder shape compared to the original Generation 1 design. For simplicity, this guide refers to them as G1, G2, and G3—representing Generation 1, Generation 2, and Generation 3 bellhousings. The G3 bellhousing was introduced with the DOHC J-Series engines, beginning with the J30AC used in the TLX Type S.

ENGINE	BELLHOUSING
J25A	G1
J30A1	G1
J30A4	G1
J30A5	G1
J30AC	G3
J32A1	G1
J32A2	G1
J32A3	G1 from 2004-2006, G2 from 2007-2008
J35A1	G1
J35A3	G1
J35A4	G1
J35A5	G2
J35A6	G1 & G2 Depending on Year
J35A7	G1
J35A8	G2
J35A9	G2
J35Y1	G2
J35Y2	G2
J35Y5	G2
J35Y6	G2
J35Z1	G2
J35Z2	G2
J35Z3	G2
J35Z4	G2
J35Z5	G2
J35Z6	G2
J35Z8	G2
J37A1	G2
J37A2	G2
J37A4	G2
J37A5	G2