I wish you the best of luck, the 3.90:1 r180 was (supposedly) only used for 6 months on the front of the 720 4x4 pickup.
I have one that came with my car as a spare that I'm told is an R180, but it may really be an R190, which I'm told is more common, or even an R160. Without taking it apart I don't know how to tell the difference. It looks like it will bolt to a R180 moustache bar, if that helps. If you have any insight here let me know, I'll check for you. The ring gear is stamped 39:10 so it is definitely a 3.90:1. It is not an R200, those are easy to spot.
Anyway, I'm in New Mexico, email me if you're interested. I don't mind shipping.
x-ring(at-sign)zcar(dot)com
Ty
Edited for fat fingers.
[This message has been edited by x-ring (edited September 20, 2003).]