Transmission

[74blackvette]

Has anyone (and I’m sure they have) swapped thier 3 speed auto for a od trans? If so what trans would bolt right in and what additional parts are needed.I talked to a local trans shop and they want 6000 to do the od trans and 12000 to put a 4 speed standard....I thought these prices were both foolish

 

[gdh]

Ridiculous, seems he didn’t want to do the work. If you decide to move to a std go with a 5 or 6 sp. A US company, Silver Sport modifies the Tremec 5 & 6 speeds to fit our C3’s. You’d need a new bell housing.

 

[taylorsk8]

I could be wrong...but:

700R4 Go in pretty easy, not direct bolt in but close. Many people upgrade them before they install in their cars.

I think a 200R4 would go in too but not sure how they would handle the power (i am not real familiar with them)

Tremec 5 or 6 speed will go in but takes more parts. Many companies sell kits for this

T

 

[rfh928]

Has anyone (and I’m sure they have) swapped thier 3 speed auto for a od trans? If so what trans would bolt right in and what additional parts are needed.I talked to a local trans shop and they want 6000 to do the od trans and 12000 to put a 4 speed standard....I thought these prices were both foolish

I used to have a 78 4-speed, but a neighbour of mine had the same year auto...and he swapped it out back in the early 2000's for a 4-spd o/d auto. No idea of the details, but I know he wouldn't have done it unless it was reasonably priced.

 

[Sergio79]

A few years ago I was offered a rebuilt 700R4 for $1500, plus installation, plus other possible surprises. The guy was a Corvette mechanic but he was clearly not interested. His price was without changing the shifter i.e 3 speeds shifter with a 4 speed tran. From surfing the forums, it seems that there is different quality of rebuilt and different versions of 700R4. The more recent versions have some improvements the older ones don’t have. Go to a good transmission guy and plan for $2500 minimum. Good luck.

 

[Tourmax]

700r4 will bolt up and is a mechanical 4speed/od transmission.

you will need to work out your linkages and a way to mount the TV cable to the carb. TV cable is essential, without it (or installed incorrectly) will result in bad shifting or (worse case) destroy the transmission. 700r4 is probably the easiest and least expensive option (assuming you 74 is an auto already). 700t4 will also have a mechanical speedo drive. Thats a plus for your car.

4l60e is just (essentially) an electronic 700r4 and will also bolt up. You still would need to work out linkages and have to add a standalone controller. Some sensors (like a tps) are also needed.

big bonus of the 4l60e (or any electronically controlled trans) is you have total control over when and how it shifts and it opens up the possibilities of things like paddle shift, etc.

Standard opens a whole other kettle O’ fish. Get something out of a sbc so the bellhousing/flywheel/pressure plate/etc all match. Then you need to hang the third pedal and assorted cables and switches.

Driveshaft is likely to need altering no matter which way you go.

I’m up annapolis valley way. You?

 

[74blackvette]

700r4 will bolt up and is a mechanical 4speed/od transmission.

you will need to work out your linkages and a way to mount the TV cable to the carb. TV cable is essential, without it (or installed incorrectly) will result in bad shifting or (worse case) destroy the transmission. 700r4 is probably the easiest and least expensive option (assuming you 74 is an auto already). 700t4 will also have a mechanical speedo drive. Thats a plus for your car.

4l60e is just (essentially) an electronic 700r4 and will also bolt up. You still would need to work out linkages and have to add a standalone controller. Some sensors (like a tps) are also needed.

big bonus of the 4l60e (or any electronically controlled trans) is you have total control over when and how it shifts and it opens up the possibilities of things like paddle shift, etc.

Standard opens a whole other kettle O’ fish. Get something out of a sbc so the bellhousing/flywheel/pressure plate/etc all match. Then you need to hang the third pedal and assorted cables and switches.

Driveshaft is likely to need altering no matter which way you go.

I’m up annapolis valley way. You?

im in the digby area,a lot of good info! Reason I was looking to go with the 200r4 is I’ve been told that will just go in no modifying anything which sounds easy ha ha,I would love to go manual transmission but the cost is more than I’m willing to spend. My 74 is my first vette but I hope to get a newer one aswell within a couple years so I’m trying to not to tooo overboard with this (though I’ve already put 25k in it)

 

[Tourmax]

im in the digby area,a lot of good info! Reason I was looking to go with the 200r4 is I’ve been told that will just go in no modifying anything which sounds easy ha ha,I would love to go manual transmission but the cost is more than I’m willing to spend. My 74 is my first vette but I hope to get a newer one aswell within a couple years so I’m trying to not to tooo overboard with this (though I’ve already put 25k in it)

Just outside kentville here.

About the only place the 200r4 will have it over a 700r4 is it's the same (or similar) length as a th350. So if you're putting in a car that had a TH350, you can reuse the driveshaft.

BUt a 200R4 is going to be hard to come by compared to a 700R4. The 200 wasn't offered in a lot of models, where the 700r4 came in just about everything from economy cars to full size trucks. The 200 gearing is closer to the stock TH350 than the 700r4. The 700 has a little deeper lower gears and the overdrive isn't quite as high as a 700.

Other than that, you will have the same concerns like the TV cable and such.

200-4R vs. 700R4 Transmissions: A Comparison - Gearstar Performance

200-4R vs. 700R4 are the two four-speed automatic transmissions always being compared side-by-side for their similarities, yet unique differences. Read on!

gearstar.com

 

[grumpyfellow]

My 74 has a turbo 400

 

[74blackvette]

Mine currently has the turbo 400 aswell.im going to switch to a od trans once I get the car back from paint...but now I hear there’s also an issue with my vacuum advance...put a cam intake heads and holly carb but apparently I have an issue somewhere so I’ll have to get that addressed first

 

[Tristan69]

HD Turbo 400 with shift kit and high stall. Depending where you are you may get lucky finding what you want at a salvage yard. Cheap to rebuild any trans yourself. The prices you were quoted are crazy talk

 

[Tristan69]

And now with gas prices so low just enjoy the ride

 

[grumpyfellow]

That’s a good fix for the effect. Shift kit and higher stall. Do you want the over driver for highway cruising. Because you could change reared gear to do that as well.

 

[Tourmax]

TH350/400 are interchangeable. Both the 4L60E and 700R4 will bolt right up. At least to the back of hte engine. the rest is a bit more involved. Do-able, but more involved.

Interesting trivia:

4l60E grew out of the 4L60, which grew from the 700R4, which has it's roots in theTH350.

4L85E grew out of the 4L80E, which grew out of the TH400.

The th350 line was meant to deal with the power output of the SBC, the TH400 was meant to handle higher torque engines, which is why it ended up in trucks a lot. It's also why it's more difficult to get a 4L80E in place where a 4L60E used to live. It's physically bigger in almost every dimension.....