I cannot specifically help you as the E-brake "should" hold the truck the same uphill or downhill. But if you do not have the service manual to your truck here is a link: http://chevy.tocmp.com/1948_51truckshop/index.htm
Somebody on this site will have better trouble-shooting skills and lead you in the right direction.


Always get a 2nd opinion, especially if I am the source of the 1st opinion.