I installed a new CMS tilt.trim on my boat and realized that I tore off the skeg last outing on the boat ramp due to low water. I decided to take the lower unit off to check for other damage. Need a new housing so ordered a complete one. However when I took off my old lower unit two pieces came falling out and I have no clue where they go. One is a yellow plastic sleeve with teeth inside but only on half of the inside (teeth match the drive shaft) and a rubber sleeve that is fatter on one end and has teeth on the inside as well. these teeth also match the drive shaft. Do these go on the upper shaft? And if so, which way and which order do they go? It is a 1979 2 cyl Mercury 40hp. I have looked through my manuals and online and can't even seem to find these pieces mentioned. Help would be greatly appreciated.