Pontiac Alley - Pontiac GTO Transmissions

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Pontiac Alley - Pontiac GTO Transmissions

1. Source Serial Number Code (Automatic & Manual)

These codes were stamped on the left side near the top forward of the housing. Manual transmissions were stamped on the case. From 1964-66 transmissions carried a source serial number, which consisted of a plant prefix letter, a production date and a day/night shift suffix. Example: R520N=Muncie,4 Speed built on May 20 during the night shift. In 1967 the serial number was changed, it consisted of a plant prefix letter, year number, and month produced (with a letter code instead of a number).

A-January	B-February	C-March
D-April	E-May	H-June
K-July	M-August	P-September
R-October	S-November	T-December

Example: N7C18=Muncie,4 Speed built on March 18.

Some late model 1967 and beginning in 1968, the car's last eight numbers of the VIN were stamped on the transmission. There are exceptions to the rule. Source Serial Number Code/Plant Prefix Letters

Prefix	Plant	Transmission Type
A	Cleveland	Manual Powerglide
B	Cleveland	Turbo Hydra-Matic
C	Cleveland	Powerglide
CA	Hydro-Matic	Turbo Hydra-Matic
D	Saginaw	Overdrive
E	McKinnon	Powerglide
H	Muncie	3 Speed
K	McKinnon	3 Speed
L	GM of Canada	Turbo Hydra-Matic
M	Muncie	3 Speed & Overdrive
N	Muncie	4 Speed
O	Saginaw	Overdrive
P	Warner Gear	3 & 4 Speed
P	Muncie	4 Speed
R	Muncie	4 Speed
R	Saginaw	4 Speed
S	Muncie	3 Speed
S	Saginaw	3 Speed
T	Toledo	Powerglide
X	Cleveland	Turbo Hydra-Matic
Y	Toledo	Turbo Hydra-Matic

2. Model Identification Code (Automatic)

These codes were stamped on a metal tag located on the right side of the transmission. Exceptions are 1965, they were stamped them either on a metal tag or the low servo cover and in 1966 they were stamped on the low servo cover.

1964

64=Model Year

30=V8 Engine Application

135=Built on the 135th day of the Year

1965

65=Model Year

40=GTO Application

135=Built on the 135th day of the Year

1966

66=Model Year

NA=GTO Application

135=Built on the 135th day of the Year