Hello..My name is Josh and I have a 1978 Corvette. When I had my engine rebuilt a while back, the 'vette mechanic mentioned to me that the transmission in my car is made out of cast iron. I got up under the car and checked it out and sure enough it is cast iron.

He also said that it being cast iron is a rare thing for the 1978 Corvettes. Something about there being a shortage of aluminum that year thus the usage of the cast iron for my 4 speed.

I am wondering if anyone here can tell me if that is in fact a rare transmission...or if all the 4 speeds in '78 were in fact cast iron.

Thanks,

Josh

 

Noone ever heard this before????

 

Sorry, not me.

 

Why the "winking"? lol

Is this a stupid question I am asking...like were all 1978 4 speeds cast iron or something?

 

if i am right in 78 gm put in 4 speed cast iron[ saginoff tranny ],not shure of the spelling, the m 21 and 22 are white metal, [aluminun] THE ROCK CRUSHER,I WOULD SAY THE MUNCY IS THE BETTER OF THE 4 TRANNYS THE CAST IRON IS GOOD BUT A GRAPY GEAR RATIOS.GM MAKES A T-10 ALUMINUM TRANY TO AND A LOT OF PEPOLE GET THEM MIXED UP FROM THE M 21 & 22 ... HOPR THIS HELPS, I HAVE REBUILT ALL 4 OF THOSE TRANNYS. SO IF YOU HAVE ANT QUESTIONS LET ME NO

 

OK, thanks for the info. The bad gear ratio must be why the car feels like it has a 4:50 gear in the rear end. LOL

Is there anyway to find out how many vettes were made with the cast iron tranny in 1978?

 

let me do some reserch for you and i will get back to you i will also find out what kind of ratios it has,if you could give me the numbers off the case e-mail to me wallacex2000@yahoo.com

 

OK, thanks. I have this number that was on the drivers side of the trans case. The numbers stamped were larger than your average codes...22127.....is that the number, or is it on the passenger side?

 

I believe these numbers were also stamped on the trans casing but smaller...GM6261888

 

Hello,

I have a '79 Corvette Coupe with a 4-speed. The engine rpm is at 3500 at 70 mph. Is there a better transmission w/overdrive that woulkd bolt in?
I'm thinking a Richmond 6-speed or would changing the rear end gear ratio do the trick?

Thanks,

Steve