Need help with C4 not wanting to shift into 3rd?

[65stang289]

I dont have a clue what this is at all. It was doing good first and second gear shift just fine but cant get third. I try to feather it in and some times it will go. Now when I fight to get it in third it runs and then down shifts its self in second. Anything help woud be good. Its a streetfighter C4

 

[10secgoal]

try adjusting the band, and checking to make sure the vacuum modulator is getting vacuum.

 

[MaresMotorsport]

sorry this is an older post, but my 66 is doing the same.

how do you adjust the band?

 

[rbohm]

to adjust the bands follow this procedure;

the adjusting points for the bands are external,one front,one back on opposites sides of the trans,tighten the front one to 10-12ft/lb and back off 1-1.5 turns,tighten the rear one to 10-12ft/lb and back off 2 turns.