Hi new to this site, I have a 2004 chevy silverado 1500 4x4 extended cab that has a vibration at 55mph plus. I’ve replaced the rear driveshaft, rear axle seals and bearings and had the new driveshaft rebalanced at local driveline shop and still the vibration persists. Any help or knowledge would be appreciated.

 

Why did you not just have your original drive line rebalanced? Unless it was bent somehow, that's what I'd have done.

 

original was bent

 

Good enough for me.!

Do you know why or how it was bent?

 

Sounds like you got some excess play in your ring and pinion. I had a ranger with a vibration around 40-46. Replaced the rear end and made everything smooth. I could really tell when I had it up on the lift. I could rotate the pinion almost an inch before the wheels would turn. The new rotates about a 1/4 or less and the wheels turn.