Some of us have drive line vibration and the most common causes are:
- unbalanced tires.
- brake drum lost its balancing weight.
- dented unbalanced drive shaft
- sloppy transmission mounting
- universal joint problems
- rear wheel bearings
- wear in the rear differential.
I have checked all these items, everything was OK, but I still had a little vibration above 60mph.
This year before the yearly inspection I wanted to give the emergency brake cables a good grease job.
I dismantled the rear brakes and noticed that, after removing the three little retainer screws, the drums were hard to remove.
This is caused by the brake shoes: there is wear inside the drums, but a small rusty "ridge" of material is left and
the drum is "clamping" over the brake shoes. To make removing the drums easier next time, I removed the ridge with a course round file.
After assembly I took it for a test ride and the driveline vibration is gone!
My theory is that the brake shoes are normally scraping this "ridge" , turning it into a vibration above 60mph.
I just wanted to share this information.