1969 L89 with automatic

[Ralph S.]

Re: 1969 L89 with automatic

I have some figures from someone that worked at the Tonawanda plant showing 272 L71 M40 engines produced & 46 L89 M40 engines

[Terry M.]

Re: 1969 L89 with automatic

There are more differences in the CY TH400 than the torque convertor and the additional friction plates. The case is thicker as well as other differences. I remember a story in The Restorer about the CY transmission. Those of you with interest and a more accessible Restorer collection might wish to look it up. CY was not the only TH400 HD transmission that was produced over the years. Some pick-up trucks got a version as well.

Ralph -- those numbers you have are for engines produced, not necessarily cars built. They always produced more engines than cars built in order to account for damage along the way. You should also know that the source those numbers came from said the 1969 numbers (and 1970 numbers) are not accurate because of the lengthily 1969 model year. They counted engines built after August 1969 as 1970 engines even though they were for 1969 Corvette or Camaro production. At that time the other engines they were building, except for Corvette or Camaro, were for 1970 production. That is why I have not posted those numbers -- they are meaningless and only serve to confuse.

[Dick W.]

Re: 1969 L89 with automatic

There are more differences in the CY TH400 than the torque convertor and the additional friction plates. The case is thicker as well as other differences. I remember a story in The Restorer about the CY transmission. Those of you with interest and a more accessible Restorer collection might wish to look it up. CY was not the only TH400 HD transmission that was produced over the years. Some pick-up trucks got a version as well.

Ralph -- those numbers you have are for engines produced, not necessarily cars built. They always produced more engines than cars built in order to account for damage along the way. You should also know that the source those numbers came from said the 1969 numbers (and 1970 numbers) are not accurate because of the lengthily 1969 model year. They counted engines built after August 1969 as 1970 engines even though they were for 1969 Corvette or Camaro production. At that time the other engines they were building, except for Corvette or Camaro, were for 1970 production. That is why I have not posted those numbers -- they are meaningless and only serve to confuse.

And remember all the ZL-1 M-40 engines that were on that list? Agree that it would not compute if you were trying to figure out how many cars were built using the engines.

[John S.]

Re: 1969 L89 with automatic

Thank for all the info on these CY automatic cars.
The car I am checking out to buy is an early build roadster. S705XXX.

Does anyone know an NCRS inspection contact for the Memphis area to inspect the car for me?

I am in AZ. Will fly to check it out personally, but would like to have an expert check it for me too.
Thanks,
John

[Patrick H.]

Re: 1969 L89 with automatic

Thank for all the info on these CY automatic cars.
The car I am checking out to buy is an early build roadster. S705XXX.

Does anyone know an NCRS inspection contact for the Memphis area to inspect the car for me?

I am in AZ. Will fly to check it out personally, but would like to have an expert check it for me too.
Thanks,
John

Mark Donnally is in northern Kentucky and may be able to help. If it were me I'd be calling him.

[Chris H.]

Re: 1969 L89 with automatic

I once drove an LS6 which I believe used the same trans. I was skeptical prior to driving it. On the highway at 60 mph, I floored it, the thing down shifted with a bang and I swear chirped the tires. That motor tranny combo was awesome. That thing shifted faster than any human with a 4 speed. One of the reasons drag racers use automatics and not 4 speeds.....

[Steve B.]

Re: 1969 L89 with automatic

Mark Donnally is in northern Kentucky and may be able to help. If it were me I'd be calling him.

I agree 100% with Patrick. Marks inspections are first rate.

[Ralph E.]

Re: 1969 L89 with automatic

John,
FWIW back in July 1969 Car Life Magazine did an article "Five Ways to Go with the Fabled 427" They compared all types of combo with engines and transmission. If you can find the article it is very good and informative. As for the THM400 they rav about it. Said "if you can overcome the mystiques of a four speed you are in for a surprise" They state the THM is perfect for the L88/L89.
I wonder how it was to drive an automatic L88 with an idle speed of 2000 rpm.

[Richard M.]

Re: 1969 L89 with automatic

Speaking of CY transmissions, I am looking for a speedometer drive gear for mine anyone out there
have a lead on a 16 T, orange gear, p/n 8623311.
Please let me know.
Richard

[Joe L.]

Re: 1969 L89 with automatic

Speaking of CY transmissions, I am looking for a speedometer drive gear for mine anyone out there
have a lead on a 16 T, orange gear, p/n 8623311.
Please let me know.
Richard

Richard-----


GM #8623311 was only fairly recently discontinued. I would think there would still be some "around".

[Ronald R.]

Re: 1969 L89 with automatic

I have several of these cars or CY trannys, years ago it was reported there were 255 of the corvettes built in 69. I did a guesstimate by serial number and date and that looks to be close for corvetts. I bought a crate CY trans from a drag guy in Denver, I have only seen 2 other loose tranys and bought both. They all have a 6 bolt torque converter and the material on the case is slightly different ( looks like magnesium?) . The oil pan is also different. I went thru this drill many years ago and can dig up other facts if important. These yellow tag CY's were only available in SHP cars or across the counter.
thanks RDR

[Richard M.]

Re: 1969 L89 with automatic

My CY case looks like magnesium too. Here is some CY information that I found interesting:
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.


I believe the CX trans was used in Chevelles, Camaros, Novas and Impalas.

[Ronald R.]

Re: 1969 L89 with automatic

There was a detailed discussion years ago witha survey of CY trannys and SN/date relationship, If anyone is smart enough to retreive this info! I believe the consensus was around 300 total production thanks RDR

[Kenneth B.]

Re: 1969 L89 with automatic

I had a 1969 Camaro 396/375 HP auto. The heavy duty transmission was mandatory When you drive one there is no doubt that its a different one than the standard. Damn thing was scary the way it shifted. I assume the Corvette used the same one.

[Ronald R.]

Re: 1969 L89 with automatic

yes all SHP GM cars with auto would have the CY