The gear is attached to the starter shaft with a one way or overrunning
clutch. This is often referred to as a "Bendix". This prevents the armature
from being over run and destroyed during the brief moment when the engine
starts and the solenoid is released. Most likely it is bad.

Dennis

>From: William Greenamyer <greenamyer@YAHOO.COM>
>Reply-To: William Greenamyer <greenamyer@YAHOO.COM>
>To: vanagon@GERRY.VANAGON.COM
>Subject: Starter won't engage ring gear when sit for a while
>Date: Fri, 7 Sep 2007 06:59:20 -0400
>
>I have a problem where if I let the van sit for a period of time (say a
>week
>for example), when I first try to start it, the starter will not engage the
>ring gear.  The starter works but it acts like there is a flat spot on the
>ring gear or the starter gear is hitting the ring gear rather than the
>teeth
>on the ring gear.  If I go back and turn the engine slightly, sometimes it
>will then engage but not always.  In looking at the ring gear, there
>doesn't
>appear to be much of any wear on the teeth so I am guessing that there is a
>starter problem or there is some kind of an alignment problem somewhere.
>In
>the past, the problem that caused this was a worn trans housing bushing
>(the
>copper bushing that goes on the end of the starter shaft) or one of the
>trans to engine bolts was not tight.  Even with that, there didn't appear
>to
>be any real wear on the starter gear or ring gear.  Once I get the starter
>to engage, it is usually fine for the rest of the day.  I need some ideas
>on
>this.  How much edge wear on the ring gear can cause this?  Is the starter
>lubrication at fault?  Is there another alignment problem that I have not
>considered?
>
>William