4 speed to maybe 5 ??
Thread Starter
4th Gear
Joined: Sep 2010
Posts: 4
Likes: 0
4 speed to maybe 5 ??
just bought a 71 corvette 454 with 4 speed, i knew when i bought the car it had a problem with the transmission. The car pops out of 4th gear usually when letting of the gas if i hold the gear shifter it will stay in gear. . I dont know a good mechanic in the Denver area , I also dont the cost for the work that needs to be done.Now heres the question do i rebuild the transmission currently in the car or put the money towards a 5 speed ? looking for some advice, thanks
Melting Slicks
Joined: Sep 2004
Posts: 2,655
Likes: 19
Figure out what you're going to use your car for, hiway, long cruises, weekends just around town, weekend drags, etc. Then figure how your engine is setup, ie high rpm, big cam, etc, then figure what your rear end ratio is and how that works with your driving habits.
For me, I wanted the best in all situations, I went with a Richmond overdrive 6 speed. Pretty much a direct replacement for the muncie, works with your mechanical linkage, and you can chose gear ratios to work with your rear end ratio.
For me, I wanted the best in all situations, I went with a Richmond overdrive 6 speed. Pretty much a direct replacement for the muncie, works with your mechanical linkage, and you can chose gear ratios to work with your rear end ratio.
Melting Slicks
Joined: May 2004
Posts: 2,743
Likes: 845
From: Gulf of America
2023 C7 of the Year Finalist - Unmodified
2018 C3 of Year Finalist
For the exception of my new motor, the Tremec TKO-600 was the best thing I have done to my car. The OD really makes the car enjoyable to drive. Depends on what you plan to do with your car.
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
5 speed. No need to put a non overdive trans into the car unless yo uare inot NCRS. It makes the car much more fun to drive, quieter on the highway. I liked the 5 speed so much after a few years I went to a 6 speed now. 
Le Mans Master
Joined: Oct 2006
Posts: 7,123
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From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
What shifter is in the car- original stock or a Hurst? It could be as simple as bushings being worn and not getting it into 4th all the way, or even the stops on the Hurst shifter not being adjusted correctly. I'd check those first- it's away cheaper fix that either a rebuild or a 5-6 speed swap.
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
It certainly was not a bolt in. I used a T56 6 speed from an 06 GTO. It required major surgery to the crossmember. I had already made mine removeable when I changed over the the 5 speed but it required a large section to be removed and I welded in a piece and had to fab it up for the 6 speed. It was not an easy task but well worth it. The T56 is a real nice shifting trans and the GTO gear ratios are real nice.
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Burning Brakes
Joined: Oct 2002
Posts: 914
Likes: 14
From: Aberdeen, Scotland
6 speed vs. 5 ...
Gordonm,
I figured that with the torque of our cars a six speed would be not required; alot of shifting when you could "ride" the wave of torque
Now this is based really on nothing. I have driven a '66 vert with a 502 and a 5 speed. I must admit not being overly impressed with the transmission. That was a TKO. I did like the long leggedish of the car however.
With my "new" engine complete I would like to go with a 5 speed, I liked the Classic Chevy kit. Can you give any details why you like the 6 over the 5?
What is the deal with the Richmond 6 speed? Almost a direct swap? If so why don't people use them the Richmond transmissions vs. the TKO.
Carbster
I figured that with the torque of our cars a six speed would be not required; alot of shifting when you could "ride" the wave of torque
Now this is based really on nothing. I have driven a '66 vert with a 502 and a 5 speed. I must admit not being overly impressed with the transmission. That was a TKO. I did like the long leggedish of the car however.
With my "new" engine complete I would like to go with a 5 speed, I liked the Classic Chevy kit. Can you give any details why you like the 6 over the 5?
What is the deal with the Richmond 6 speed? Almost a direct swap? If so why don't people use them the Richmond transmissions vs. the TKO.
Carbster
Melting Slicks
Joined: Sep 2004
Posts: 2,655
Likes: 19
Good question on the Richmond. They dont sell a "kit", probably because you dont need one.
I liked it because of the availability of dozens of different gear ratios. With a newly rebuilt 3.08 rear end, I was worried a 0.64 would be too high of a gear. The Richmond was available with a 0.76 OD.
There are 3 modifications to use it in your vette.
1) Trans mount needs to be moved back and down. I cut mine shorter and made a new rubber mount that was 1/2" lower.
2) Output yoke (th400) might bind on speedo gear, although mine did not. They recomend cutting it shorter.
3) Shifter; it comes with the Long shifter. If you want it to look like the original 4 speed, buy a 67 Hurts t shifter handle. It bolts directly to the Long shifter
Bolts to your bell housing, uses the same clutch linkage, mechanical speedo screws in, shifter in stock location, no drive shaft mods....
Price of a ROD (about $3k) is about the same as a $2k TKO with the $1k mods you need to get it to work in a vette.
Pick your input spline count and gear ratios.
http://www.richmondgear.com/07pdfs/RG21.pdf
I liked it because of the availability of dozens of different gear ratios. With a newly rebuilt 3.08 rear end, I was worried a 0.64 would be too high of a gear. The Richmond was available with a 0.76 OD.
There are 3 modifications to use it in your vette.
1) Trans mount needs to be moved back and down. I cut mine shorter and made a new rubber mount that was 1/2" lower.
2) Output yoke (th400) might bind on speedo gear, although mine did not. They recomend cutting it shorter.
3) Shifter; it comes with the Long shifter. If you want it to look like the original 4 speed, buy a 67 Hurts t shifter handle. It bolts directly to the Long shifter
Bolts to your bell housing, uses the same clutch linkage, mechanical speedo screws in, shifter in stock location, no drive shaft mods....
Price of a ROD (about $3k) is about the same as a $2k TKO with the $1k mods you need to get it to work in a vette.
Pick your input spline count and gear ratios.
http://www.richmondgear.com/07pdfs/RG21.pdf
Last edited by Garys 68; Sep 27, 2010 at 08:38 AM.
Race Director
Joined: Apr 2000
Posts: 17,676
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
I was wondering about that Richmond 6 speed, says it's a repacement for the 4x3 trannys in the C4's also only comes in
fine spline input shaft ?
I have a 3.08 rear gear and TKO 600 .64 OD. The torque of my previous 406ci and my current 427ci small block make cruising on the highway a pleasure, especially when a new car comes up fast behind you thinking you you are a stock C3.
You can also get a higher .87(?) OD gear too
1700 RPM @ 70 mph or 1900 @ 80mph I got 24 mpg on the highway with the 406ci @ 80mph and you put your foot into it and no hiccup or hesitation it takes off.
I am doing a test right now with 427ci, first city mileage then I am going to see what I get on the highway. The 427ci is over 600HP and I bet I get over 20mpg on the highway, I am going to cruise at 70-80mph and I would not be surprised to see the same or better milage than the 406ci
fine spline input shaft ?
I have a 3.08 rear gear and TKO 600 .64 OD. The torque of my previous 406ci and my current 427ci small block make cruising on the highway a pleasure, especially when a new car comes up fast behind you thinking you you are a stock C3.
You can also get a higher .87(?) OD gear too
1700 RPM @ 70 mph or 1900 @ 80mph I got 24 mpg on the highway with the 406ci @ 80mph and you put your foot into it and no hiccup or hesitation it takes off.
I am doing a test right now with 427ci, first city mileage then I am going to see what I get on the highway. The 427ci is over 600HP and I bet I get over 20mpg on the highway, I am going to cruise at 70-80mph and I would not be surprised to see the same or better milage than the 406ci
Last edited by MotorHead; Sep 27, 2010 at 06:51 AM.
Burning Brakes
Joined: Oct 2002
Posts: 914
Likes: 14
From: Aberdeen, Scotland
Richmond!
Gary,
You nearly have me convinced. I will do a little research. No kit sounds good. As I am currently out of the country working until I return I need to have a decent shop do mine! I am still looking for the shop. I "thought" I had a guy, but really anything a little out of the box he really did not want to do and the hour rate which looked "good" merely meant more hours were "needed". I like the idea of the different ratios as well.
Back years ago when I had a '78 Trans AM with built 400 and a 4 speed I lusted after a Richmond OD!
Carbster
You nearly have me convinced. I will do a little research. No kit sounds good. As I am currently out of the country working until I return I need to have a decent shop do mine! I am still looking for the shop. I "thought" I had a guy, but really anything a little out of the box he really did not want to do and the hour rate which looked "good" merely meant more hours were "needed". I like the idea of the different ratios as well.
Back years ago when I had a '78 Trans AM with built 400 and a 4 speed I lusted after a Richmond OD!
Carbster
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
If you do a lot of highway driving, an overdrive transmission might be necessary. Otherwise, a 4-speed is plenty good for any other situation. If you are going to be road racing the car, maybe 5 or 6 speeds might be better...but I don't think that's your situation.
If you don't really need the overdrive ratio in the 5/6 speed trannies, just replace the links and bushings on the shifter/tranny. If that doesn't fix it, get the 4-speed rebuilt. Lots less expensive....and it already fits!
If you don't really need the overdrive ratio in the 5/6 speed trannies, just replace the links and bushings on the shifter/tranny. If that doesn't fix it, get the 4-speed rebuilt. Lots less expensive....and it already fits!