Saturday, August 28, 2010


You are looking at the front of another customer's Saab V4 transmission, mounted in my factory transmission press. The gear with the large teeth is the pinion gear. Above and to the left of that gear is a screwed-up input shaft hub. Inside that hub is the freewheel unit. The pulley-looking thing sticking out of the hub is whats called a "dog clutch" gear. Someone with probably good intentions had welded on half washers to hold the dog clutch engaged, rendering the freewheel inoperative, or as we call it,"neutered".

The problem with this neutering method is that it throws the main shaft out of balance, and makes it impossible to ever revert to freewheeling again. This is really not a good way to neuter the freewheel.

Here is the main shaft after I removed it from the transmission. You can clearly see the dog clutch piece dangling from the freewheel hub of the main shaft. Hmmmm.....what to do to save the expensive main shaft and dog clutch....hmmmm....

I put the sucker in my lathe and began to cut off the half washers, by cutting through the welds. This is the cutter set-up on the carriage fixture on my lathe. I have made the first cut in this picture.

This is the second and final lathe set-up. The cut has gone through the welds and is into the half washers. My hope--at this point--was that the welding had not screwed up the freewheel hub. If it had, the mainshaft was junk.

VOILA! The cut is completed. The owner got lucky. The main shaft, the dog clutch and even the freewheel parts inside the hub were all still good. All I had to do from this point was to use the lathe cutter to clean up the end of the freewheel hub.
The point of this? There is a right way and many wrong ways to do something. This was one of the wrong ways that I managed to correct. I WILL neuter the freewheel, but do it the right way, so nothing is out of balance, and should the owner [or subsequent owner] ever get soft in the head and want to make the freewheel function again, he [or they] can do so.

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.