Captbachus

I just bought a 1976 Corvette and have noticed that the car barely stays in 2nd gear before shifting to 3rd. I know the L-48 isn't going to be very fast but this shifting really seems to eat into the performance I should be getting. Has anyone else experienced this and if so, what did you do to fix it?

page62

I replaced it with a 200-4R overdrive transmission from Bowtie Overdrives. Within 3 months of buying my car. 2½ years ago. Haven't regretted it!

toadster

curious why you chose the 200R4 over the 700R4.

ElCid79

I chose the 700r4 personally... But the 200r4 is good because it is more or less a direct bolt on... less fabrication, and modification is necissary...

PigPen

Same setup on my '76. I've never really noticed any short shifts. Does it stay in longer with full throttle. Shift points should be low under low power, and have much higher shift points under full load. If not, it might just be your vacuum modulator. I recently put a shift kit in mine with an adjustable vacuum modulator - like it a lot. ~$50

aharte

You could shift it manually. That's what I do with mine.

There are adjustments to change the shift points, but I unfortunately can't help you with that.

page62

Both transmissions, when properly built -- not a junkyard warrior -- will provide good service in a Vette. However...

The 200-4R is a direct bolt-in replacement for the TH350. The crossmember does not have to be replaced, and the driveshaft doesn't have to be cut. Both of these things must be done in order to install a 700-R4.

Also, the 200-4R has gear ratios more similar to a TH350. The 700-R4 has a very tall first gear. Bottom line: with a 3.08 or lower rear gear, go for the 700R4; with 3.55 or higher, get a 200-4R.

Captain_Kaboom

I have a '77 L48 w/3 speed auto. I think I get into 3rd somewhere around 40 mph under moderate acceleration.

I added a Trans-Go shift kit, and manually pop it into 3rd when I feel like shifting!

tom102

Sounds like a bad modulator on the transmission, its an easy change though

Captbachus

Mine does shift more quickly at lower throttle, it barely stays in second gear for 2 seconds before shifting to third. My wife's boss at work had a 1976 that did the same thing. He told her we should have the modulator checked.

How involved is it to install a shift kit? I had a friend who used to own a 1969 Camaro with a shift kit and I remember it shifting very crisply from gear to gear. I haven't done any work on a car in about 15 years but would like to start doing some of the work myself.

Thanks for the response

Captbachus

My wife's boss said the same thing. Are modulators available at auto parts stores or through a dealership?

Thanks for the response.

tom102

I would get it from Chevrolet, it is not an expensive part. At least you will know it is the right part for your transmission.