As you both have the 722.6xx you have two choices of fluids; the MB fluid for the 722.6 or the newer fluid used in the 722.9xx.

http://www.peachparts.com/shopforum/showthread.php?t=163343&highlight=722.6+fluid

When I change mine I intend to use the newer product.

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)