I have a 1986 FLTC Tour Glide and just got done with replacing the trasnmission main shaft oil seal. In fact, I had to do the job twice. The second time I realized that since the sleeve which the oil seal rides on wasn't mirror smooth, the leak continued. That sleeve which fits over the transmission main shaft has to be replaced if it doesn't have a chrome mirror dead smooth shine. Also, there is a spring on the inside of the oil seal that easily falls out of position when the sleeve in inserted into the oil seal. Here is a big hint: smear oil on the sleeve and the oil seal first, insert the sleeve into the oil seal, make sure that thin O-ring is in position on the shaft, and that the champhered end of that sleeve is pointed to the transmission and over the thin O-ring. If the spring on the oil seal came loose when you inserted the sleeve, you can reposition it before installing the oil seal. If you inserted the sleeve first, and the oil seal onto the sleeve, you wouldn't know if that oil seal spring came loose. Once the oil seal is on the sleeve, place the sleeve into position on the main shaft. If you don't have a special installation tool to set the seal, simply use a flat piece of anything you can use to place on the seal and and edge of the case and tap the seal into position with hammering on that flat piece to make sure the seal doesn't go beyond the edge of the case. Whatever you do, don't set the seal any deeper than the edge of the case. If you do that, the seal will be making contact with the face of the shaft bearing.