Gregory,

I get the same symptom on my Vanagon; when it happens it is always at the
top of a long hill.  Like you said, it comes on when I upshift to 4th, and I
can make it go away when again downshifting to 3rd.

I think it has to do with oil foaming as I recall either reading or writing
about it here on the list some years ago.  Not completely sure, but I think
when the engine is slanted to the rear, the oil level is higher for the 2
rear cylinders thus creating more agitation.  The light/buzzer comes on
because the oil is less dense and therefore the oil pressure is lower.

I think the solution is to always keep the oil level slightly underfilled.
I have noticed that when I keep the oil level of the lower side of the
acceptable range this doesn't happen very much.

Now why it happens in the first place I can't really explain.  I seems the
design of the WBX should certainly have accounted for situations where the
oil level is in the higher part of the acceptable range and Vans might drive
uphill for a while.  So maybe it means that our oil pumps are a bit worn,
but that is just a guess.

I am sure other more experienced WBXers will reply also to provide some
info.

Roland

On Mon, Mar 30, 2009 at 10:49 AM, Gregory S. Morrison <
gsm@gregorysmorrison.com> wrote:

> Dear Vanagon Gurus: While driving on the interstate this weekend the oil
> light came on and buzzed when driving in 4th gear as we came to the top of
> a
> grade. It would go out and stop buzzing if I shifted down to 3rd.
>
> This has never happened before this weekend.
>
> I checked the oil level and it was normal.
>
> When the transmission was rebuilt several years ago we had a taller 4th
> gear
> installed for less engine strain and better gas mileage at freeway speeds.
>
> Thanks,
> Greg
> 86 Syncro Westy
>