Barry,    My mechanic also was prepared to lower the drive shaft to
replace my fuel sending unit.  Ron at the Bus Depot got me one cause my
VW dealer wanted $140.00.  As it turned out,  it was only the wires
(they missed this at the first diagnosis).  So be sure it is not the
wiring!   I was about to call Ron to see about a return but if you need
a sending unit I will sell you mine (brand new ) at the same price I
paid Ron ($125.00) and I will pay the shipping.
Marlin,   '87 Syncro GL