My 1990 Vanagon Multivan (automatic tranny) is having transmission
problems.  The few weeks ago, a family member was driving it down the
street when it started going slower while requiring more rpm.  We
pulled over right away.

Going in reverse works fine.  Going forward doesn't.  It makes a
slight whining sound while requiring excessive rpms to move forward
slowly.

We had it towed home and then let it sit for a few weeks while we
pondered the problem and looked into getting help.  Today, we started
it and it drove off just fine... for about a block, and then
exhibited the same symptoms.

A friend suggested that it might be a plugged filter, and that we
should remove the filter and see how it runs.

Does that sound plausable?  Is removing the filter something I can do
myself with a little courage and tools?

- Ken