Clutch Replacement Learnings

[Hladun]

Replaced the clutch on my78SC because of clutch spin/drag problems. Transmission shifts very easily now with no reverse gear crunch. Process went quite well, and here are some things I learned.

First, two floor jacks; one under the engine and one under the transmission mounts make removing the engine and transmission assembly very easy. You can hold up the trans as you lower the engine and not damage the shift rod. You can also use the second jack under the transmission when you separate it from the engine. I recommend taking engine/transmission out together.

My pressure plate spring had cracked and this caused the clutch spin/drag. It made shifting into first and second hard and reverse grind. I had posted a clutch drag question previously but only got “usual suspect” answers to adjust the clutch cable. I think a lot of the 915 hard shifting legends are probably the result of pressure plate spring problems.

There is a poor design in the clutch. The pilot bearing guide tube has the trans input seal in it. Don’t forget to change that seal! (If you buy a new guide tube from our host the seal is not in it. The seal’s hidden on the transmission page.) Any leakage past that seal has the trans fluid migrate down the guide tube into the heart of the clutch assembly. It mixes with the clutch dust to form a sticky black goo. I drilled a small hole just ahead of the seal so if I ever get leakage it will hopefully leak out behind the throw out bearing.