What you propose is not quite as easy as just unbolting all the auto
stuff and adding the manual stuff. The '81 ratios are close enough to
not be a major concern but the mounting and linkage parts for the '81 4
speed are different than waterboxer 4 speed stuff.  Use a tranny and
everything from an 83.5 or newer waterboxer and it will be simpler as
everything will bolt right up. The 80-83 aircooled tranny and engine
mount closer to the front of the vehicle. You will have to either move
the '81 tranny back and extend the shift linkage or move the engine
forward and deal with the various lines. Don't forget that you need a
waterboxer flywheel and clutch.

Mark

ok artguy wrote:
>
> I perused the archives on the Vanagon page, but I couldn't find any
> definitive answers from someone who's attempted this. I have a '90 with a
> 2.1 and a bad auto trans, and an '81 with a good 4spd trans. I know the
> ratios are different from aircooled to watercooled, but can this trans still
> be used? Can I just transfer the trans and linkage from the '81 directly to
> the '90? And help/insight would be much appreciated. Thanks-
>
> Jon
>