Knocking noise

[Bryan C. Robertson]

My 66 Riviera makes a knocking noise beginning around 10 mph increasing with speed and stops around 45 mph.  Does the same in reverse order when slowing down. I suspect it's the drive shaft, what do you gentlemen think.

[Str8-8-Dave]

Might well be a U-joint.  Rusty ones go ricky      ricky   ricky rickyrickyicky   as they speed up.  The poor old guy from Pennsylvania a few doors down the street from my teenage home had a 64 Ford Galaxie and I noted each day with a pencil mark on our garage door jamb each time it went by the house as he drove to his job at Kelsey Hayes.  One fine morning it went out under its own power then about 45 minutes later came back dangling from a local tow truck which deposited the car, driveshaft hanging, in his driveway.  I crawled under it and fished the driveshaft out of it and replaced front and rear U-joints for him in his driveway.  No more ricky    ricky  ricky rickyrickyicky after that...

Edited September 18, 2022 by Str8-8-Dave (see edit history)

[EmTee]

The center bearing or its mount is another possibility.

[John348]

I found that a lot of times if it is drive shaft related the noise will go away as you ease off the throttle and coast with the vehicle in neutral unloading the driveshaft of engine torque. I always found a vibration was associated with center bearing problems, but that was on 58-64 X frame Chevy's where I am certain that was a different design. You need to isolate the location of the sound, front, back, or center.  

[Graham Man]

U joints are easy to swap out and cheap, when were they greased last?  Take it for a little ride just a few miles, if it is a u joint, it will be hot when you get home.

 

 

Is this what your drive shaft looks like?  Looks like a carrier bearing and 5? U joints? Interesting center joint, looks like they sell replacement driveshafts also.