Changing 3 speed to 4 speed

[k belknap]

My '81 Vette came stock with 3 speed. I absolutely hate it. I would like to change to a 4 speed. Can anyone tell me if a 4 speed transmission and a stock Corvette 4 speed shifter will work with little or no modification? Any tips you can give me would be greatly appreciated!

Thanks,

Kevin

[Patrick H.]

Re: Changing 3 speed to 4 speed

K,

This may sound funny, but are you talking automatic or manual shift transmissions? Since no 1981 MY cars came with 3 speed manual transmissions, I assume you are talking automatic.

Yes, it is possible to swap, as they put a 4 speed auto in the 1982 Corvette as the only transmission. I believe that several articles have been written about this type of swap in the magazines such as Corvette Fever, Vette, etc. I believe that some modifications to both the shifter assemblies and the transmissions mounts need to be made. Anyway, I would suggest even calling Corvette Fever and ask when they last ran such an article. Hope this helps.

Patrick Hulst

[Patrick H.]

Re: Changing 3 speed to 4 speed

K,

This may sound funny, but are you talking automatic or manual shift transmissions? Since no 1981 MY cars came with 3 speed manual transmissions, I assume you are talking automatic.

Yes, it is possible to swap, as they put a 4 speed auto in the 1982 Corvette as the only transmission. I believe that several articles have been written about this type of swap in the magazines such as Corvette Fever, Vette, etc. I believe that some modifications to both the shifter assemblies and the transmissions mounts need to be made. Anyway, I would suggest even calling Corvette Fever and ask when they last ran such an article. Hope this helps.

Patrick Hulst

[Patrick H.]

Re: Changing 3 speed to 4 speed addendum

By the way, its probably cheaper and easier to buy an 82 than to modify your 81...

Patrick

[Patrick H.]

Re: Changing 3 speed to 4 speed addendum

By the way, its probably cheaper and easier to buy an 82 than to modify your 81...

Patrick

[Joe L.]

Re: Changing 3 speed to 4 speed

Patrick----

Yes, my thoughts exactly. If Kevin has an original '81 3 speed manual, he better not change it; he's got the only one in existence. It would be a shame to destroy such a "rare bird".

[Joe L.]

Re: Changing 3 speed to 4 speed

Patrick----

Yes, my thoughts exactly. If Kevin has an original '81 3 speed manual, he better not change it; he's got the only one in existence. It would be a shame to destroy such a "rare bird".

[k belknap]

Re: Changing 3 speed to 4 speed

It is an automatic :)

[k belknap]

Re: Changing 3 speed to 4 speed

It is an automatic :)

[Patrick H.]

P.S. Another question for you, k

K,

So what is so bad about the 3 speed THM? Just want to make sure that there isn't something else that could be fixed other than replacement.

By the way, in the 4 speed manual vs. auto argument, an automatic of the THM variety will make a Corvette feel SIGNIFICANTLY different than a manual trans version. One of my friends had the same MY Vette as me, with the only difference in running gear being the trans, his being an auto. They were as different in character as you could expect! And it was he who also had headers, not me! The difference in response and "Corvette feel" was amazing. The auto felt like it really HAD a "slush box" in there.

Patrick

[Patrick H.]

P.S. Another question for you, k

K,

So what is so bad about the 3 speed THM? Just want to make sure that there isn't something else that could be fixed other than replacement.

By the way, in the 4 speed manual vs. auto argument, an automatic of the THM variety will make a Corvette feel SIGNIFICANTLY different than a manual trans version. One of my friends had the same MY Vette as me, with the only difference in running gear being the trans, his being an auto. They were as different in character as you could expect! And it was he who also had headers, not me! The difference in response and "Corvette feel" was amazing. The auto felt like it really HAD a "slush box" in there.

Patrick

[George Daina]

Re: Changing 3 speed to 4 speed

The biggest obstacle in this change would be to mound the clutch pedal. Another dilema facing this swap is the bracket for the Z bar. If you don't have it, you will have to get it welded in place. You won't be able to buy the bracket, so fabrication is your only option, or, cutting one off from a manual trans frame. To do this, you may have to take your own torch to the scrap yard. You may have to play with the console and floor board opening if the shifter does not come up in the stock location.

These are some of the problem areas to ponder.

[George Daina]

Re: Changing 3 speed to 4 speed

The biggest obstacle in this change would be to mound the clutch pedal. Another dilema facing this swap is the bracket for the Z bar. If you don't have it, you will have to get it welded in place. You won't be able to buy the bracket, so fabrication is your only option, or, cutting one off from a manual trans frame. To do this, you may have to take your own torch to the scrap yard. You may have to play with the console and floor board opening if the shifter does not come up in the stock location.

These are some of the problem areas to ponder.

[k belknap]

Re: P.S. Another question for you, k

There's only one thing I don't like about the 3-speed. It runs the rpms too high!! I'm running between 3,500 and 3,600 rpm at 70 mph. I'd prefer to get that down to about 2,500. Speaking of this transmission, when I go from park to 3rd (drive), the back end of the car actually dips down, like the cars raring to go. Also, this transmission shifts HARD when going into second!! It actually spins the tires for just a moment. Does this sound normal?

Thanks for the help!

K

[k belknap]

Re: P.S. Another question for you, k

There's only one thing I don't like about the 3-speed. It runs the rpms too high!! I'm running between 3,500 and 3,600 rpm at 70 mph. I'd prefer to get that down to about 2,500. Speaking of this transmission, when I go from park to 3rd (drive), the back end of the car actually dips down, like the cars raring to go. Also, this transmission shifts HARD when going into second!! It actually spins the tires for just a moment. Does this sound normal?

Thanks for the help!

K