CY & CX 400THM: differences & similarities
 

Using a 1969 "Hydra-matic Production Parts" list, I charted the differences and similarities between the "CY" & "CX" automatic transmissions, as well the difference between the "CY" & "CX" and the standard 400 automatic transmission.

https://www.yenko.net/attachments/400THM.jpg

Re: CY & CX 400THM: differences & similarities
 

That's Real Nice work Rob. https://www.yenko.net/ubbthreads/imag...iggthumpup.gif

Re: CY & CX 400THM: differences & similarities
 

Very nice Rob and very helpful!

Re: CY & CX 400THM: differences & similarities
 

Rob, To help the inept, like myself which vechicles used a CY or CW and what is diff between them (CW/CY). My ORIGINAL 70 Z-28 (bought NEW) with column shifted T-400......may I assume this had either of the two???
Thanks, Chuck

Re: CY & CX 400THM: differences & similarities
 

For the year 1970:
*TH400 CY Trans. was coded for the LS6 Chevelle,& Corvette LS5.
Higher-shift point and stronger bands & springs.I believe a thicker shaft as well?
*TH400 CW Trans. was coded for the L78 Chevelle-Nova-Camaro,& LT-1 Camaro-Nova.
*TH400 CR & CS Trans. was coded for the LS5 Chevelle-Monte Carlo,& Corvette w/Transitorizied Ignition.
*TH400 CF Trans. was coded for the L34 Chevelle-Camaro-Nova.
*TH400 CK Trans. was coded for the 300HP 350cid Corvette.

Re: CY & CX 400THM: differences & similarities
 

Chuck, the comparison is between the CX vs. the CY, not the CW version. The CW was used in the L78's, LT1's etc...

Re: CY & CX 400THM: differences & similarities
 

Ray Morrison sent me some more 400-THM info. It was an application chart for 1969, so I went ahead and ran it through Excel so it's easier to digest...

https://www.yenko.net/attachments/118862-400RAY1.jpg

1968 CY Trans details
 

Here are some detailed pictures from a 1968 CY THM400 trans, courtesy of Tommy K and the Super Car Workshop...

https://www.yenko.net/attachments/132661-12.jpg

Re: 1968 CY Trans details
 

VIN...

https://www.yenko.net/attachments/132662-13.jpg

Re: 1968 CY Trans details
 

Writing...

https://www.yenko.net/attachments/132663-14.jpg

Re: 1968 CY Trans details
 

Stamp...

https://www.yenko.net/attachments/132664-15.jpg

Re: 1968 CY Trans details
 

Here are some detailed pictures from a 1969 CX THM400 trans, courtesy of the Super Car Workshop...

https://www.yenko.net/attachments/132923-CX1.jpg

Re: 1968 CY Trans details
 

6-lug convertor...

https://www.yenko.net/attachments/132924-CX3.jpg

Re: 1968 CY Trans details
 

Entire assembly...

https://www.yenko.net/attachments/132925-CX2.jpg

Re: 1968 CY Trans details
 

What Car is this trans going into,if I may ask?

Re: 1968 CY Trans details
 

Tommy K's blue Harrell nova https://www.yenko.net/ubbthreads/imag...ns/worship.gif https://www.yenko.net/ubbthreads/imag...ns/worship.gif https://www.yenko.net/ubbthreads/imag...lins/beers.gif

Re: 1968 CY Trans details
 

The 69 CX was from the 69 Dana Nova, the 68 is Tommy K's 68 Gibb/Harrell #44 Nova...BKH

Re: 1968 CY Trans details
 

That Yellow CX tag looks very nice.
Has it been restored,unrestored,or is it a new replacement that are available today?

Re: 1968 CY Trans details
 

100% original tag. Just cleaned...BKH

Re: 1968 CY Trans details
 

Where is the VIN located on this transmission.

Thanks

Re: 1968 CY Trans details
 

Forgot to ask if anyone has a source for speedometer drive gears for TH 400?


Thanks

Re: 1968 CY Trans details
 

I have compiled a list of speedometer gears.
What specifically are you wanting to know?
Color-Ratio-Part#?

Look for a CON VIN possibly stamped around the bell housing as well as into a recessed machined pad located were the Trans. oil pan meetes the trans. valve body.
It's behind the shift linkage rubber boot.
It is parallel to the head pipe,so you will have to look behind the head pipe,and wipe the pad clean to notice.

Re: 1968 CY Trans details
 

Mr70,

Thanks for the reply. I need the stock replacement gear for a TH400 with 3:55gears. Someone had changed it when they changed the tire size.

Re: 1968 CY Trans details
 

Gear Part #9780470,Gray in color with 44 teeth used on 3:55 ratio with F70X14,G70X14 tires on 1968 Chevelle-Elco-Camaro.

Re: 1968 CY Trans details
 

What are the shift points on the L78 th400 trans setup under full throttle application? If you just start out in "drive" and floor it, at what rpm will it shift fron 1-2 and then 2-3?? Trying to dial in the trans in one of my cars with th400 and 4.10 rear.

wilma

Re: 1968 CY Trans details
 

Any th400 experts have some feedback???

thanks, wilma

Re: 1968 CY Trans details
 

I want to say my L-78 TH400 Chevelle fitted w/4:10/F70X14 shifts from:
1-2 @ 10-15MPH.
2-3 @ 18-25MPH.
I can double check the RPM for you this week.. https://www.yenko.net/ubbthreads/imag...ns/burnout.gif

I see a 70 Nova L-78 w/3:55/E70X14 shifts from:
1-2 @ 7-12 MPH.
2-3 @ 18-35 MPH.

Re: 1968 CY Trans details
 

Wilma...look at the chart at the beginning of the thread, and grab the numbers for the governor parts...see if ya can't still get those parts (maybe even from GM)...if you can, problem solved... https://www.yenko.net/ubbthreads/imag...lins/beers.gif

Re: 1968 CY Trans details
 

The 1970 L-78 CW TH400 trans. used Governor #8626866.

Re: 1968 CY Trans details
 

I just found a CW turbo 400 trans with a 6 bolt converter-supposed to be out of a 70 Z28. How much are these going for? The guy wants a grand for it-is that out of line???

Re: 1968 CY Trans details
 

I'd buy it for that.
What's the VIN# stamped into the machined pad on the drivers side,just above the shift linkage behind the rubber boot?
Can you read the Pass. side aluminum tag as well?

Re: 1968 CY Trans details
 

rangelec
I wanted to reply to your question in the 6-lug convertor thread about this TH400,so I thought this topic was better.
The 1970 CW is a seldom seen scarce Transmission.
1970 CW TH400 was designed for specific Solid lifter BB & SB Applications.
They were:
*Chevelle-Nova-Camaro L-78 402/375HP.
*Camaro Z/28-Nova LT-1 350/360HP Yenko Deuce.
Not knowing it's overall condition,I'd say it's worth the 1K regardless.

Re: 1968 CY Trans details
 

I have the CW coded trans in my 70 Z28. What is different about this transmission over a CX or CY tranny and any other unique features. It also has the 6-bolt converter.

Paul

Re: 1968 CY Trans details
 

Hello everyone, I'm confused, which one would go in a 69 Camaro or Chevelle L-78, a CW, CY , CX or CC? , Thanks

Re: 1968 CY Trans details
 

1969 Camaro & Chevelle used the CX TH400,as well as other solid lifter applications.
1970 was new for the CW suffix TH400,in the L-78 & LT-1 Camaro-Nova-Chevelle.

Re: 1968 CY Trans details
 

To Wilmasboy:

My research has said that the design upshift speed at WOT of the 69 CY trans was 5900 to 6100. The high speed governor will help you up your shift points but also affecting shift timing are line pressure and accumulator springs and pistons. Also the trans was designed for hard use as all wavy shift plates from clutch packs were removed for harder as well as quicker shifts. Some other mods were the forward clutch drums have 2 oil bleed check balls instead of 1, this allows oil to dump faster to speed shift timing. The 6 lug convertors were first used in trucks so you can find trucks with the same convertor shell but everything inside is vastly different. Frank

Re: 1968 CY Trans details
 

Would you happen to have the list for the 68's

Re: 1968 CY Trans details
 

I believe it's gonna be the same...except the converter is different, which according to Ray Morrison flashes in the ~1800 rpm range...

Re: 1968 CY Trans details
 

Here's the tag on a "CY" in a neighbor's all-original '71 LS-6 Corvette:

http://img.villagephotos.com/p/2002-...TH400Plate.jpg

https://www.yenko.net/ubbthreads/imag...lins/beers.gif

Re: 1968 CY Trans details
 

[ QUOTE ]

The 6 lug convertors were first used in trucks so you can find trucks with the same convertor shell but everything inside is vastly different. Frank

[/ QUOTE ]

Frank,

I recently found a 69 CX THM400 out of an L/78 Nova. I now
need the correct 6-lug converter. I see them on eBay from
time to time, but you comment about the truck converter
being vastly different concerns me. How does one know if
you have a true SHP 6-lug converter? Or, are they still
available from GM with the proper internals for an L/78?
https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

BTW, were the SHP converters stamped or coded in any way?
Steve