I had issue with leaks around same area. Turned out not to be the cover, but the case joint adjacent.

Story and pics of finding the solution here ( there are other posts on same subject where I was scratching my head)

https://shufti.wordpress.com/2011/07/01/vanagon-syncro-transmission-oil-change-with-complications-solved/

Alistair

> On Apr 16, 2016, at 2:10 PM, Gilles H Turmel <gilles.turmel@SYMPATICO.CA> wrote:
> 
> Hi, I have an 89 Westy Syncro and loosing oil from the reverse gear idler cover. I’ve emptied the thanny and redo the joint with a gasket maker, torque the bolt to 10 Nm. After 1 month of running oil leak again from the same place. I have Total Transmission Gear 7 (80W-90) syntec oil in the tranny. Is there a gasket maker I should be using?
> Best regards.