Hello, I am restoring a 69 convertible and need help with the wiper motor transmission. I have been working n the car for several years but have never used the wipers. While testing things out the other day I found the wipers will not rotate though a full cycle. After removing cal I found that the motor was not able to rotate due to the transmission arm being to long and binding. I looked and found no adjustments. The motor is a 40-140 model and when unhooked will spin completely around. I was afraid that maybe the previous owner may have swapped out transmission arms for one that had concealed wipers. Does anyone know the length differences in the concealed and non-concealed wiper transmission. Thanks for your help.