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TRANSMISSION IDENTIFICATION
The transmission identification code will differ depending the type of
transmission - Manual, Powerglide or Turbo Hydra-Matic 400.
The manual and Powerglide will have a production code consisting of a
prefix letter designating the assembly plant, a production date (year/month
letter/day number) and a shift code for day or night shift if the assembly
plant was using two shifts.
The Turbo Hydra-Matic 400 was introduced in the 1967 Chevelle and coding
used a different format. This production code consists of a two-digit model
year (68) followed by an engine/model code letter and a three-digit production
date. The three-digit production date begins with the first day of
January, 1967. For example, a production date of 298 would be October 25,
1967 or, the 298th day. January 1 of 1968 would be number 366.
A Julian date
calendar can be found here to assist you. Remember, a production date
of 001 to 365 is calendar year 1967
and 366 or higher is calendar year
1968. If the production date is over 365, subtract 365 and find the corresponding
Julian date for 1968. It's not known when the last TH400 was installed
in a 1968 Chevelle, but assuming July 31 the last model build day, a date
of 577 should be the largest date. July 31, 1968 (577) is the 212th day
of 1968 (a leap year). Subtracting 365 from 577 gives you 212 - July
31, 1968.
A typical Muncie 4-speed would be dated such as P8K01 and will decode
as P (Muncie 4-speed), 8 (model year), K (month - July), 01 (calendar day
01).
| Manual and Powerglide Transmission Designations |
| 3-speed |
4-speed |
Powerglide |
Turbo Hydra-Matic |
M - Muncie
H - Heavy Duty Muncie
K - McKinnon Industries
S - Saginaw
O - Saginaw O.D.
W - Warner Gear |
N - Muncie
P - Muncie
R - Saginaw |
C - Cleveland
E - McKinnon Industries
*T - Toledo
|
X - Cleveland
B - Cleveland
Y - Toledo |
| The coding of the
Muncie 4-speed manual transmission continued the same as 1967. A
letter designated the month and the model year was included. For
example, P8A01 breaks down to P (Muncie), 8 (1968
model year), A (January), 01 (day). Any Muncie build in
calendar year 1967 for an August
through December built 1968 model
year would be dated with M through T (August through December) such
as P8R25 meaning the transmission was coded for a 1968 model year
Chevelle on October 25, (calendar year) 1967. |
| Year - 8 |
|
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| Calendar Month |
| M - August |
P - September |
R - October |
|
| S - November |
T - December |
A - January |
|
| B - February |
C - March |
D - April |
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| *E - May |
H - June |
K - July |
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Day Number
1...31 |
Powerglide Transmission
Variations have been found for Powerglide transmission designations.
Normal code would be the plant letter, model year, month/day such
as C8H21 for Cleveland (C), 1968 (8) June 21(H21) or C8C15 for Cleveland,
1968, March 15. However, plant variations have surfaced, particularly
Fremont, where nothing seems to make much sense. One Fremont plate
has TP08P07 while another has T8P01D. The first probably decodes
to Toledo Powerglide (TP), 1968 (08), September 07 (P07) where the
second is probably Toledo (T), 1968 (08), September 1 (P01), day
shift (D). |
Turbo Hydra-Matic Transmission
A sample TH400 code would be 68C298 where "C" indicates
a Chevelle or Camaro w/396 engine and 298 indicates October 25,
1967.
The 3rd character (letter) is designated as follows:
A - 396 cid
C - 396 cid
D - 327 cid
E - 396 cid
H - 396 cid |
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