new tranny or overdrive...

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Jan 23, 2007 | 10:39 PM

#21

mrvette

Team Owner

Joined: Jul 1999

Posts: 65,492

Likes: 230

From: Orange Park Florida

Quote:

Originally Posted by markdtn

I have a 700R4 and 3.7 gears. first gear is useless. I would recommend 3.36 or even 3.08 with a 700R4. That would be the best of both worlds.

HELL, I had a 700 in there, and with my 336 , it's first gear WAS totally useless, lasted about 2 seconds, even at relatively heavy throttle, then the 2nd gear would wind forever...shift kit and all....

the C4 of similar weight/gearing had mostly 273 or 308 rears, and they did fine with the 700, for long as it lasted....

HELL, for that matter with any automatic a 273 rear is plenty, if I could smoke hell outta posi273 rears and wide tires with a 5500 lbs GRANDVILLE Pontiac.... I suspect a car weighing a ton less could get up and GO, and it wasn't a 700 either with that silly first gear, it was a 400 turbo....

every automatic I heard of has similar gearing to a 200 4r....same as 350/400 turbo, the rest, Ford, Mopar....whoever...

5-8 speed automatics are for diesel trucks....

Jan 24, 2007 | 10:26 AM

#22

markdtn

Le Mans Master

Joined: Aug 2003

Posts: 7,720

Likes: 12

From: Chattanooga TN

Quote:

Originally Posted by kaiserbud

Markdtn - 1st is useless? - can you give more info?

Crash80 - hmmm - I didn''t realize that.

I have a complete Tuned Port out of a '90 C4 in my car. It has all the low end torque you could want in a cruiser street car. With the low 3.7 gears when you stomp it, it just smokes the street tires and the rpm at 70 is higher that it has to be (tach is broke and I haven't fixed it yet). Also, when you come off a light up a slight grade, you are in 4th gear so fast that the converter locks and it lugs the engine unless you give it some throttle or shift down to 3rd at every light. To me, a 3.36 or 3.08 would be better. I would have less rpm up top, and I don't need the gear down low for my application.

Jan 24, 2007 | 10:45 AM

#23

76custompaint

Racer

Joined: Oct 2004

Posts: 379

Likes: 0

From: Thief River Falls Minnesota

Yep if you want to go the gear vendors route be prepared for some major tranny tunnel hacking, take it from a guy who knows. =) We went with a 700-R4 and a Gear vendors unit, to cut down on that big drop from 1st to 2nd in RPM's.

76CustomPaint

Feb 6, 2007 | 11:26 AM

#24

davewsr

Cruising

Joined: Jun 2006

Posts: 12

Likes: 0

overdrive

So I have a 1980 C3 with the same problem.
What transmission can be directly bolted into the car? and what do you
do about the gear shift?
Is this transmission used in any other Chevrolets. For example I have a
1985 Suburban with the overdrive tranny and a blown engine. The transmission is very recent overhaul. Is it the same or could it be??

Feb 6, 2007 | 11:54 AM

#25

sly vette

Safety Car

Joined: Oct 2005

Posts: 3,570

Likes: 1

From: Algonac Michigan

http://forums.corvetteforum.com/show....php?t=1611105
I am just in the begining of this thread and for those of you considering a T5 swap I am going to detail as much as poss and I will also help with a auto to manual swap! As much as I can, BerniesVette will be the guy with most of those answers, he did the auto to manual swap.

Feb 6, 2007 | 12:13 PM

#26

rj8806

Melting Slicks

Joined: May 2005

Posts: 2,826

Likes: 3

From: Tennessee

Heck, we all know swapping a 5 speed into an automatic car can be pricey

but if you follow sly vette or BerniesVette you can swap a T-5 into it relatively cheap. Once you go 5 speed you will wonder why you didn't go that route sooner.

If I can answer any questions, please let me know.

Richard
Tech Support
Keisler Engineering

Feb 6, 2007 | 12:38 PM

#27

75coupered

Instructor

Joined: Sep 2006

Posts: 192

Likes: 0

From: Fort Lauderdale FL

Quote:

Originally Posted by Shirley1978

this might be way out of your budget but when i swaped my automatic to a TKO-600 from keisler i didnt recognize the car... it was sooooooo much better

it was a butt load of money but in my opinion itle pay for itself in gas with todays prices..(might take a while though

)

i have zero regrets
jonny

Depends on what you want to get out of your car and how you drive it but a 5 speed will transform the car completely in every respect, performance and economy. In my case I had a TH400 with 2.88 rear and got 14.5 sec quarter with it and about 18 mpg 3000 rpm at 80mph.
Then a TKO with the 0.68 OD, switched rear to 3.54, now get 12.5 sec quarter, 31mpg at cruise 1800rpm at 80mph. Performance way up, economy almost double and fun factor up X10, but then again I like to row through the gears. In the city, I just throw it into 3rd and nevery have to change

Feb 6, 2007 | 02:05 PM

#28

ESU

Drifting

Joined: Jun 2004

Posts: 1,881

Likes: 9

From: staten island ny

With a 3.73 rear you should go with the 2004r tranny. Lower than that, 3.08, 3.36 go with the 700r. The gearing matches up better that way. Go to bowtie overdrives website, very informative on whats needed.
ESU