C4 has no 2nd gear

Hi All, I just bought a 72 Ford F100 with a C4 and I have no second gear while it shifts automaticaly. I can manually shift through the gears and everything works just fine but when in D it sounds like it slips for a quick second between 1st and second and the goes right into 3rd gear. Also the kickdown will not work since it uses 2nd gear. I checked the vacuum lines to the modulator, they are ok. Any help would be greatly appreciated.
Dave

Well after doing a little reading on this forum I adjusted the intermediate band, it did help some, instead of a split second slip it does go into 2nd for about a second before it shifts into 3rd, still seems like it is too quick of a shift though between second and third. Could this mean the intermediate band is worn? Also still will not downshift through the kickdown mode. Any suggestions that I might try? Thanks.
Dave

Check the adjustment of the downshift linkage first. Make sure you are getting wide open throttle when you press the throttle pedal to the floor.
Before going further I would need to know what your rear end ratio was and if the C4 is the one that came with your truck or has it been swapped for another.

Thanks for your reply Paul, the throttle is definitely opening all the way and the kickdown lever is at full travel. As far as I know the tranny is the original, it is a pretty unmolested truck with 81000 miles on it. The axle code is 17 on the data tag on the door.
Dave

Start with pulling the vacuum line at the modulator with the engine off. If there is oil there then replace the modulator. Be careful when replacing it because you don't want to lose the modulator pin. Buy a "Green Stripe" modulator. How did you adjust the front band? did you torque the adjusting screw to 10 foot pounds and then back it out 1 1/2 turns? If not try that. Be sure the lock nut is loose when torquing and that it is tight when you are done. If everything in these areas is OK then check the linkage adjustment. Put the lever in Drive with a rope or bunjie cord holding it in drive toward the second gear detent at the column or floor shifter. Go under the vehicle and loosen the lock nut on the linkage and shift the transmission manual lever dolidly into the Drive position. Tighten the locknut without letting the linkage slip one way or the other. Road test it and see if that fixed it. If none of the above fixes the problem then you will have to remove the valve body and check all the valves for free travel and no scoring. (this would be a good time to install a TransGo 40-2 kit in the valve body, It will add performance and years of life to your transmission.)
While you have the valve body out you check the operation of the second gear servo with 40 psi air. If it moves and you hear a clunk as you hit it with air then it is good. If your hear hissing then the seals are bad in the servo and you should replace them.

Thanks for all your help Paul, your a wealth of info. At least now I know where to go with it. I did adjust the band as advertised. After i did that it would actually shift into 2nd but not for very long, it only stays in second gear for about a second or two. I suspect I'll have to go the valve route that you described and again I am very thankful for all your help.
Dave