I've had my '87 Camaro for about a year and a half. I don't think the CC worked when I got the car and I didn't even try it until this spring. I've replaced the servo and the multiswitch. The servo is getting great vacuum even after the car is off so the back flow valve is working too. Brake vacuum and electrical switches are working correctly. The only two things left are the module and the speed sender in the speedometer. Am I wrong? What the odds of it being either of those parts? Any suggestions?

Thanks

Your assumptions are correct. However, if the speed sender (& buffer box) isn't working then the ECM won't turn on the lockup as you get up to speed. So if the lockup works then only the CC box (& wiring) remains.

I think the torque converter lockup worked when I bought it, but I switched engines and use a manual lockup switch now. Is the "buffer box" part of the cluster and therefore removeable from it, or does the whole cluster have to be replaced, and is the buffer box even a posible problem. I know there isn't a DRAC on the ECM bracket. I don't know how to proceed from here.

Thanks

I'm not sure about the maro, but on my Olds the buffer is separate from the cluster - hooked to the speedo sensor w a 3-wire (10-15") cable. It feeds the speed signal to the ECM on a brown wire, and the CC on a red wire. In the Monte the ECM also gets it on a brown wire, but the CC gets it on a yellow wire.
If you find a yellow wire on the CC-box you can try to monitor it w a voltmeter. It should jump up & down (12V/0V) as you slowly move the car.

the speed buffer box is down next to your ecm under the passenger side dash, read my title (wiring) in the electronics threads i just went through problems with my speedometer and it may have touched on somethings you may need to know, there are wiring diagrams and some pictures for you to lookover that may help you. GOOD LUCK!