Quote Originally Posted by Dave Severson
Yup, figured it had to be something simple. I believe there are a couple different flexplates with different spacings to the converter.....Don't remember how to tell which is which, hopefully someone with a better memory will jump in here....
Pull up the TCI website for more info, but there are several flex plates
10.5 and 11.5 bolt patterns plus 157 and 164 tooth ring gears then the 50 in balance and 28 inch balance to add to the confusion. There is also a 0 balance one, but only for special cases.

My guess is that you didn't have the torque converter fully in place before you started drawing down the nuts - like Dave S. has said.

To install a C4 and probably every other tran, you put the converter in place first by putting it on the male spline and rotating it until it fully clunks in place, then the trans is bolted up to the vehicle.

Another problem area is the smaller inner splined (input) shaft - it is directional as well - the shorter splined end goes into the trans itself - if installed backwards, it can damage the converter .