Overdrive
 

Hey guys i am needing info on what to look at since the 1986 chevy factory tranny doesnt go into overdrive anymore. The only thing i changed was the carb. Not sure what controls it and thanks for any help.

Re: Overdrive
 

Changed the carb from what to what? The original quadra jet to an aftermarket 4 barrel? That's dangerous ground if you don't understand how the 700r4 works. Your TV cable is definitely out of adjustment either way. It's what most people would refer to as the "kickdown" cable, but it's much more than that. It controls everything inside the transmission, not just downshifting.

Whatever you do, don't drive it until you get it fixed. A bad TV cable adjustment will blow your transmission in less than 500 miles, easy.

Re: Overdrive
 

That's good advice. Don't drive it until you get it set up. If you're handy, you could try to get it in the ballpark. Do a google seach on TV cable adjustment on a 700r4.

Re: Overdrive
 

Best way to adjust TV cable is push the D button and push it towards the firewall as far as it will go. Then full throttle the carb and it will slide right where it needs to go.

All this with the motor off of course.

Re: Overdrive
 

I changed from the factory quadrajet to an edelbrock, the tranny is the original 350 with a lock up torque converter. I assume it has something to do with vacuum but i am not sure. Thanks

Re: Overdrive
 

That would have made a small difference in advice, knowing that to begin with. TH350's don't have an overdrive. Some have a lock-up torque converter that lowers your rpm's a little, but I don't know how the torque converter lock-up works on TH350's. I know 700r4's are electronic, and don't require vacuum to work, but TH350's do require vacuum to shift properly. Are you running your vacuum line on a ported vacuum port, or a full-time vacuum port? And is it on the carb or on the back of the intake? Try swapping the vacuum lines to the transmission and see if that does it.

Re: Overdrive
 

Never mind. That was 700R4 advice.