So I have a 65 Fastback, 289 engine, C4 transmission. The Problem is that it shifts late. It seems like it takes a lot to get it to shift to the next gear. For instance I have to go up to 3,000 rpm's before it will shift into 2nd gear. I checked the vaccum line and there is plently of suction coming from it. I've been told to try adjusting the modulator but is there anything else I can do or check? Also, I have an aftermarket edlebrook intake manifold and 4v 650 carb, roller rockers and crane cam shaft so the engine does have some power, but its not fast at all because it takes so long to shift through all the gears. Any ideas?
C4 Transmission Problem
- Thread starter LimeLight
- Start date
TOM B
20+ Year Stangneter 
Adjust the bands, its easy, sound like there loose.
The intermediate band provides a crisp shift from first to second,
This band is on the left, drivers side of trany, to adjust , loosen the locknut a full 2 turns while holding the adjustment screw steady, then tighten the adjustment screw using a torque wrench set to 10 foot pounds or a inch wrench set to 120 inch pounds. the back off the adjustment screw 1-3/4 turns. Then add a dab of silicone to the lock nut and tighten it while holding the adjustment screw steady. TEST BEAT TIME
The intermediate band provides a crisp shift from first to second,
This band is on the left, drivers side of trany, to adjust , loosen the locknut a full 2 turns while holding the adjustment screw steady, then tighten the adjustment screw using a torque wrench set to 10 foot pounds or a inch wrench set to 120 inch pounds. the back off the adjustment screw 1-3/4 turns. Then add a dab of silicone to the lock nut and tighten it while holding the adjustment screw steady. TEST BEAT TIME
