Well, my seat of the pants intuition proved right. I figured this out one day shortly after my last post. I was driving, and remembered that there was a brake drum style emergency brake on the Discos,....and that it appeared loose when I pulled the driveshafts for rebuilding,.....had me wondering if that brake drum might now be off center due to wallered out mounting holes from it having been loose. I reasoned that if it was,.....a light lift on the e-brake lever would exhibit a vibration in the lever and truck at roughly the same frequency of the vibration I was feeling in the seat of my pants.

I lifted the brake lever at about 25 mph,....................and THERE IT WAS...............THAT PESKY VIBRATION!!!!!!!!!!!!!!!!!

The following Sunday, I pulled my rear shaft down, removed the e-brake drum, used stacked washers to replicate the thickness of the brake drum,.....and bolted the shaft back up to the output shaft stub.

Took it out for a quick test drive,.......................and my constantly vibrating truck...........NO LONGER VIBRATED!!!!!!!! WOOOOHOOOOO!

Now just gotta find a new (to me) drum and fasteners,...so I can pass my state inspection in October.

Now if I can just figure out why my EVAP System Leak code keeps popping up,.....I'll be golden.

Brian in Austin

Udate on the update: , the drum must just be warped from someone having left the ebrake partially on,....as the center of the drum fits around a raised shoulder on the output shaft.'

I may just have this drum turned down since its just an e-brake.