Im not sure if I understand correctly, but if you are refering to the shaft the flywheel is mounted on, this is one of the output shafts on your crank assembly. Its not really a drive axel, although I suppose it could be if you really, really wanted it to be. On the crank shaft your flywheel is on, there is a "groove" , a key way. There is also one on your flywheel as you have stated. If you are saying the "guide rail" is smashed, I am going to assume you mean the "key". This is a small peice of metal that fits into the key ways to ensure the flywheel mates correctly to the crankshaft so timing is on. Now, if you key is sheared, but the keyways are fine, jsut get yourself another woodrow key and put it in and presto. Dont try to use a substitue for the key, they are softer metal and designed to shear instead of your shaft. I hope this helps, Im not 100% sure if this is what you mean. BTW, let me know if you need parts and I can look in my shop, theres been a ton of those around here. Cheers