'69 Turbo 400 code?

[JoeC]

The 1969 hi po TH400 is CX code. Post the numbers on your trans tag on pass side and look for a vin no. on the vin pad on driver side just above oil pan.

[SS427]

I don't have the tag in front of me but, it has a large "C" screen printed in the left corner. Than there is a stamped 69-Y-xxx (date). On the right corner is a screen printed "Y". The tag is yellow in color. At the bottom is a stamped number which I am not sure what those stand for. The cars VIN number is indeed stamped on the drivers side so I feel it is an original tranny. This is the missing puzzle if I can just figure it out!

[Mr70]

On page 27 of the Sept./Oct.1969 Chevrolet Service News.
NEW CENTER SUPPORT AND SPACER RING-TURBO HYDRA-MATIC 400 TRANSMISSION.This change became effective with transmisson serial numbers and build date codes as follows:
CA-69-78912 date 464
CB-69-5477 date 465
CC-69-20716 date 464
CD-69-1309 date 472
CE-69-5693 date 471
CF-69-1057 date when built
CG-69-1403 date 472
CH-69-1011 date when built
CJ-69-12871 date 467
CK-69-4661 date 466
CL-69-1945 date 466
CP-69-5068 date 466
CQ-69-17771 date 465
CT-69-98319 date 465
CX-69-3312 date 479
CY-69-1723 date 478

This verifies that that trans.code is indeed legit in a 1969 Chevrolet car.I checked all the issues before and after this and it does not mention applications for these codes.But I would bet my eye teeth it is authentic for that SPECIAL Impala.

[Rowdy Rat]

"CY" coded transmissions were used in 1969 behind solid lifter Corvette applications - L71, L89, L88, and ZL1. This particular application is quite rare for Corvettes; I've been told the total number installed in 1969 was 255.

The specifications and internals of this transmission are identical to the "CX" transmissions.

Regards,

Stan Falenski

[SS427]

AHHH! I am getting closer, thank you Stan. It was my understanding that the Corvettes also used the CX transmission so that is a new one to me. Do you or anyone else have anything documentation pertaining to this Y code behind a Corvette or any other Chevrolet for that matter? Thanks again!!

[Rowdy Rat]

1969 Corvettes that were available with the THM 400 automatic transmission used one of three codes: CK for base engine applications (ZQ3), CL for hydraulic lifter 427 applications (L36 and L68), and the CY for solid lifter 427 applications (L71, L89, L88, and ZL1). To the best of my knowledge, the CY and CX coded THM 400s were practically identical... Revised valve body with higher shift points, fully welded torque convertor, six attaching bolts for the torque convertor, etc. In addition, Corvettes equipped with the CY automatic also received a special AX or CAX (depending upon when the car was built) code 3.36 to 1 ratio rear axle as the "performance ratio". I know of one L88/M40 that is said to have a 2.73 rear, but every other car that I have seen or know about has a 3.36. Nothing numerically higher was listed which is odd considering the fact that MANY Camaros and Chevelles with the CX transmission had 4.10s. For whatever reason, the automatic was never received well in the high horsepower Corvettes and as a result, very few were built. Resale on these 1969 cars is still substantially less than a comparable four speed car with the same engine and can be real bargains if you are able to find a nice one.

This CY transmission was also used behind 1971 LS6 Corvettes and was planned for use with the 1970 LS7 Corvette if it had been released for sale. As with the 1969 version, a 3.36 rear axle ratio was the highest numerical ratio listed.

I am not aware of any other application for the CY transmission... I guess that it would be possible, but I have not heard of any such usage outside of Corvettes.

What additional information were you looking for?

Regards,

Stan Falenski

[Mr70]

BINGO!!!
It took me a while,but I knew I had this.It is a 1969 Technicians Engineering Catalog.In house only.
It lists all the Engine,Trans.and rearend codes for the 1969 Chevrolet Carline.
It tells how to break down the Date codes as well.Even the transmission and rearends.In it it states:
CY-Coded TH400.
396/375HP Chevelle-Nova-Camaro
427/435HP Corvette
427/430HP Corvette
427/425HP CHEVROLET
All with High-shift point.
If you list all the numbers off of the tag,I can tell you the dates and other meanings as well.
By the way,I am curious as to the rearend suffix ratio.Do you know that as well?
Yes Yellow does mean Hi-Perf.

[Edited by mr70 (08-14-2001 at 05:56 PM).]