Hi Neil,
from a D6, 4R-5R, Parts Book, as the D6 U P/Book, does not have all the gear tooth counts noted--it is 18 teeth on both the crank drive gear and the mag. drive gear, the idler gear is 44 teeth.
Cheers,
Eddie B.

It’s working now!
EBC your pictures did the trick.... Not only did I get the pony running but it was running better than ever, enough to start the 318 for the first time in nearly 4 years!!!! I have many things to do before using it, one problem is the oil for the turning levers, I loose it before long (I believe it’s 30W) also what kind of hydraulic oil does this use?
Thanks again!

The oil disappearing from the steering booster is usually leaking out the drive shaft seal and adding to the transmission/bevel gear oil.

It’s not a complicated fix, but you do have to take the seat tank off and remove the booster to flip it over and unbolt the sump/pump to replace the seal. Some have oil leaking out the front where the steering clutch levers linkage pushes the plungers. That is a bit more complicated but can be done as well if that’s part of your problem.

I sent you a pm.
I need to do this procedure and need help. Oil runs out as fast as I pour it

I just re-read this thread and almost gagged when I saw $400 for a mag rebuild. I recently had my Cat 22 mag (WICO) rebuilt by OLD CROAK MAGNETOS, and it was less than $150. They said it was in good shape and didnt need too many parts, but I had broken the cap, so I decided it was time for a rebuild. That included a new cap and changing the front bearing and seal. They were also very helpful with numerous emails back and forth explaining things. My 22 now starts easy and runs better. I will be sending them a pony motor mag from one of my other Cats for rebuild. Lots of people have mag problems, or create them like I did by breaking the cap and I think a reasonable cost overhaul is well worth it. Grant.