Don't worry about it. These oils mix fine, but drain them out when you get home for long term service. 

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Don Hanson
Sent: Thursday, January 29, 2015 7:22 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Diff. Oil ?

Being on an extended trip with limited resources, I've had to top-up my transmission with a different gear oil than what's in there.  Before departure in Dec. I replaced one axle seal..the other wasn't leaking (then).  I filled with my preferred oil, Swepco.  After logging ~5000mi, so far, the other side seal has now began leaking.

   I have a 5sp manual transmission.  These seem to be rare and valuable, I know I value the way mine moves my inline VW motored van.  I added almost one quart of Lucas 80w-90w gear oil to bring the level back to the level plug...laying in the sand under the van in the Desert..Both these oils are dino-oil, and the same weight....the Lucas is/was significantly less expensive and it was available through Amazon Prime, as was an economy quart bottle pump to get it into the transmission, so I went with that.
The transmission took just short of one quart of the Lucas.
  So,  the question is:  Do the Oil Experts here think I've mixed-up a "bad" batch of gear oil that will harm my tranny during another month or two before I can get home, where I'm better equipped to replace the leaking seal and restore about $70 worth of pure Swepco?