okay, so i have a c4 automatic tranny in my '66 coupe...and i had the transmission fixed, or atleast i think so. supposeddly its a 3 speed with the low, overdrive, and drive modes, but it will only shift once, and i've taken it up to 100 mph, and it doesnt shift again...is it really a 2 speed, or is that just the way it is?

 

do you have a shift kit? if its a 3 speed something may be off

 

not that i know of...but when it says "3 speed" what EXACTLY does that mean?

 

3 Drive gears, and a reverse.

 

The C4 has 3 speeds. Final drive gear (3rd gear) is usually not an overdrive gear (unless it's been changed).

Did you install the vacuum line for the modulator? W/o the modulator hooked up, it probably won't shift very well.

Dave

 

oops. nvm

 

If it is the original 66 trans it probably is a "Green Dot" 3 speed. I have this exact trans.
If you put it in neutral and pull the shifter as far back without touching the button it will hit the detent for a1-2-3 shift. If you just put it in the "normal" drive position that we are all used to, just back from neutral,it will shift 2-3. So basicly there are 2 "Drive" positions.

I seriously doubt you got to 100 mph in "second gear" so try the above and see if that solves the problem.

 

+1 The first drive position behind nuetral is only 2-3. Then if you drop it down one you will shift 1st through 3rd. Then you have Low. No problem with your tranny as long as you are sure that you had it in the first drive selection behind nuetral.

 

Wow can't believe I didn't know that about the c4's. No wonder why mine has been bogging down from take off.

 

well, i know that the vacuum line is hooked up, i had a tranny specialist do that, and he also service it too. so i know its not that, and i dont know really what a modulator is