GMC 4000...? or 5000 series....Pictures...it's about time...

[A.T. RockDriller]

Back to what factorystock said about the " Slippery/Dry " Road selector..
It sure is what he said.....
At first I mistakenly thought it worked with the rear diff.....but no...
I had seen where the airlines from the switch dissappeared into the maze of airlines on the firewall....an then gave up and moved on..

Today....driving on a real wet, oily stretch of frontage rd near a Flying J.....
Did a couple panic stops ...with and without the selector engaged...
It seemed really effective....like a 60/40 valve on a tractor.

Kinda like early ABS...

Thanks for straightenin me out on that.