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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 Hydramatic |
M - Muncie
H - Muncie H.D.
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 |
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| 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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