First, I wouldn't put in in without adding an aftermarket oil cooler, the Vanagon weighs a lot more, and more torque slip means more heat.  The higher ratios will mean it will shift at a slightly lower speed than with the WBX tranny.  I always keep my '85 in second on any hill or when accelerating on to the freeway until 4000+ rpm anyway, which is about 55-60 rpm.  Since 2nd gear is about 3.44% higher in the  aircooled, 4000 rpm is only about 2 mph slower.  So, I don't think it's a significant difference.  Regarding the torque converter, if it was used on the 1.9 and the 2.1 is different, they likely have different stall speeds.  Someone else will have to answer that one though.  You might call German Transaxle and ask them.

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of kenneth wilford (Van-Again)
Sent: Wednesday, December 10, 2014 7:48 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Update, looking for Automatic transmission for 90 Vanagon

Since no one answered me yesterday about the Air Cooled Vanagon/Bus trans into a watercooled Vanagon I did some more research on it myself.  The late Bus and early Vanagon used the NG auto trans with a Z torque converter, no tranny cooler, and the same final drive ratio, but slightly different gear ratios for 1st, 2nd and (oddly) reverse.  Not sure how much of an effect the difference in the gear ratios would make but I am more concerned about the different Torque converter.  They did use the Z converter in Vanagons until 1985 according to Bentley but maybe I am just paranoid.
Here are the gear ratios:
Air Cooled trans: 1st 2.55, 2nd 1.45
Waterboxer trans: 1st 2.71, 2nd 1.50

Any ideas what this would do to the driveability of a 2.1l Vanagon?

If this isn't going to work then I am going to have to track down a good used Automatic transmission for a later van.  Anyone have one of those?
Anyone looking for a good used Air Cooled Auto trans?

--
Thanks,
Ken Wilford
John 3:16
www.vanagain.com