I battled something similar, and it turned out to be my fault. The HB has a notch AND a bead. I was using the notch, and did not notice the bead until one day I had the truck up on my lift and just happened to see it! Doh!!!
__________________
-Don-
'66

C10 w/factory A/C
'77

Cheyenne K5 350/465/205
'80

Custom Deluxe K20 350/465/205
'04 Denali XL
'05 DMax CCLB 4x
Have a
Hickey Sidewinder Winch and need the owners/install manual? Send me a PM with your email address and I'll forward you a .pdf