1984 Westfalia manual transmission

Recently my Vanagon has started doing a weird thing. I'll start backing out
of my driveway (or backing up anywhere) and as soon as I push in the clutch
in the van will come to an immediate halt. Violently if I am backing up at a
a faster pace. The engine does not stall or act like it will and if I keep
the clutch engaged in all is fine, until I push it in.
I replaced the clutch master and slave about a year ago and didn't have this
problem then. Earlier this year I replaced the brakes but didn't notice any
problems then either. I must admit though it feels like the brakes are
grabbing the rear wheels but it only does this if I am coasting after having
been in reverse. Coasting in a foreword direction is fine, leading me to
believe the brakes are not the culprit.

Could this be a sign that my tranny is going bad?

--
Brien K Dews CC-AWCI
www.busesbythebeach.com
84 Wolfsburg Westfalia
89 Vanagon 'Bluestar'
74 Westfalia