I have owned and driven as my primary vehicle a 77 Bronco since 1980. During that time I have rebuilt or replaced many engine, drive train and body parts. When my transmission died recently, I purchased a rebuilt C4 and converter. The installation went as expected but when I put it gear the first time... nothing happened. There is no indication that the transmission is engaging in any gear. With the engine running I can hear a clicking or rattling sound under the bell housing.
Before installation I flushed the cooling lines, primed the converter with 2qts of ATF, and the vacuum modulator seems to be working.
I suspect perhaps the wrong input shaft for the converter? or maybe a bad torque converter?