Just remembered one detail. Not sure if you need the extension wire or not. The last one I took apart had one, but it was a 1/2ton GMC longbed which would explain the need for the extension.
Also, the spring in this case went from the clevis on the middle rod joint back to the cross member.
The only reason for such a big diameter was that it is bent in the middle and putting torque on one end through the bend is actually quite a bit of stress - the big bar handles it fine.
