Transmission, automatic, 4 speed, 4T60-E, electronic

Years 1991, 1993–96, 1998–99 Models 5 Factory citations 9

Also described as Automatic transaxle, 4-speed overdrive, electronically controlled (4T60-E)Transmission, automatic, 4 speed, 4T60-E

Also documented for Chevrolet Oldsmobile Pontiac

Documented applications

Century — A-body (1982–1996)

1994–1996 Confirmed

1996: standard on the wagon, optional on the sedan

Century — W-body (1997–2005)

1998–1999 Factory-verified

shared W-body code, Chevrolet Lumina kit (page prints the code beside "Transmission-Four Speed Auto")

GM Heritage factory kit — 1997 Chevrolet Lumina, p.70.
GM factory document — 1998 buick century rpo code list, p.1.
GM factory document — 1999 buick century rpo code list, p.1.

Reatta — E-body derivative (1988–1991)

1991 Single-source

the Reatta Owners Journal prints "M13 - Transmission (only found on '91 cars)", the dating remark; Wikipedia's infobox gives the 4T60-E for 1991 but prints no code, so the unit match is by meaning

Regal — W-body (1988–1996)

1993, 1995–1996 Single-source

matched to the unit by meaning: Wikipedia gives the Regal the electronically controlled 4T60-E for 1993–1996 but prints no code; 1994 is left out because no listed 1994 kit page prints the code; the kit pages word it a four speed automatic, HMD; the description follows the merged regal-w-body-1997, century-w-body and lumina-gen2 docs, while the merged lumina-gen1 doc reads M13 as Transaxle, 4 speed automatic, HMD; shared W-body code; cited from the Chevrolet Lumina kit

GM Heritage factory kit — 1993 Chevrolet Lumina, p.73.
GM Heritage factory kit — 1995 Chevrolet Lumina, p.53.
GM Heritage factory kit — 1996 Chevrolet Lumina, p.104.

Regal — W-body (1997–2004)

1998–1999 Factory-verified

shared W-body code, Chevrolet Lumina kit (page prints the code beside "Transmission-Four Speed Auto")

GM Heritage factory kit — 1997 Chevrolet Lumina, p.70.
GM factory document — 1998 buick regal rpo code list, p.1.
GM factory document — 1999 buick regal rpo code list, p.1.

This page aggregates every documented appearance of M13 in the Buick reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.