Auto trans not shifting to 3rd any ideas?

[13sec5.0]

Im going to pick up a 67 tomorrow and Im told that the trans (not original and Im not sure what exact type) will not shift to out of 2nd. I plan on changing all the fluid before trying anything. Anybody with any thoughts or info please let me know what you think.Will this be an easy fix or something more intensive. I would like to get on the road as soon as possible.

 

[JB66]

My easy guesses are...
1. Stuck downshift lever
2. Ruptured Vacuum modulator
3. Stuck governor
4. Something real internal is broke. oops!

 

[6stang8]

Hopefully it's just the vacuum hose going to the modulator valve, or the modulator valve itself.

 

[WORTH]

My easy guesses are...
1. Stuck downshift lever
2. Ruptured Vacuum modulator
3. Stuck governor
4. Something real internal is broke. oops!

Did they still use Blue Dot's in 67? If your shift indicator had a Blue dot beside one of the drive possitions it will start off in second and only shift once to third, which he might mistake for not going into 3rd.

 

[69Rcode_Mach1]

I don't know what kind of tranny you have, but on my friends c6 he had the same problem and we looked at it and it was just the vacuum advance. That usually causes the shift related problems.

 

[13sec5.0]

Alright Ill check all those things except the internal and if that dosent work then I guess Ill know it may be something internal. Thanks for your recomendations.