Eplebnista

En route to Sharks in Columbus I began to detect a low rumble from my left rear that kicked in about 45 mph and continued until it was drowned out by other sounds once I hit 80+. Checked wheels and tires and all seemed good, noise continued on the trip home. Got home, looked under the car wayward parts, shifted exhaust, loose heat shield etc. and found nothing. Swapped rear wheels and tires from one side to another and eventually went to this years "Little Mermaid" edition of Frenzy. The noise remained on the way and on the way home.

It is not loud and my nagravitor can barely hear it from the passenger seat. To me it sounds like a bomb group of B-17's headed to Regensburg or Schweinfurt of in the distance. It is not present at lower speeds and does not seem to change pitch on turns.

Over the winter I put in new upper dogbone bushings on the rear and new boge reds on all corners. To my recollection, the sound did not appear after doing that work. Pre-Columbus, I R&Red the steering rack, put in new motor mounts and replaced the oil pan gasket. The noise appeared after doing that.

This could be a bad rear wheel bearing and I could easily replace that, but the sound has now existed for hundreds of miles without change. Changing the bearing and not solving the problem would not make for a happy Otto. I have trans mounts sitting in a box on a shelf but my existing ones still have decent clearance. Trans mounts seems like a longshot.

Any and all musings, experiences, suggestions and random thoughts are welcome.

Thanks

Speedtoys

Does it change on accel -vs- decel? If it does, swap axle sizes, then it will growl the other direction than on the other side.

90% its an axle (CV joint).


Which ONE is it? Change both.

Mrmerlin

I would suggest that you tighten the shock struts use a gun an electronic gun works too
I had all kinds of strange noises coming from the back of my car until I tighten them and I just put new shocks in The center strut nuts were slightly loose

Jerry Feather

We just went thru this in another recent thread, and what Stan calls out was the exact solution to that problem. On the other hand, what this sound like is bit like when I had a failure of one of my rear wheel bearings. However, that progressed very rapidly to a near total failure before I took it apart and replaced both of the rear bearings. I think Stan is correct for your situation.

Petza914

Wheel bearing?

drscottsmith

Mine was very much like yours and was the bearing.

NoVector

I had that noise 10 years ago. Like Jeff suggested, the first thing I did was swap the axles but the sound remained in the right rear. I didn't have the wherewithall, time, or tools to change the bearings so I took it to a shop. He put it up on a hoist and with someone in the vehicle hitting the gas while it was in drive he went around the backend with a stethoscope. Iscolated it to the bearings and replaced them.

Mrmerlin

check the shock struts first = Free
No Joy,
NUTZ...
Then replace the wheel bearings = Not free

Eplebnista

Thanks gents. I will employ my impact gun first. If that fails, Robin is already primed to drive the car while it is on the lift while I hunt with my stethoscope. I never thought I would regret replacing the cats with an X-pipe and doing the RMB.

I will provide updates on my progress and eventual resolution.

Jerry Feather

If you can drive your car around town and still hear the noise, I would suggest that you go drive around your neighborhood and make some aggressive right turns to see if the noise gets a bit louder or increases in any way. You might even take some left turns to see also if the noise lessens when the right bearing is loaded more.

If you can't hear the noise around town then you might try something similar and faster on your favorite winding mountain or canyon highway, if you have either.

Eplebnista

Gents:

Hit the shock nuts with my impact. No change.

Put the car up on the lift, started it and popped into 5th. As Gomer Pyle used to say "Surprise, surprise, surprise!" Pops and thunks and what looks like excessive movement from the passenger side axle at the outer joint.

Here is a video - https://drive.google.com/file/d/1uCl...ew?usp=sharing

Given the intermittent nature of the noise, I suspect my outer CV joint has gone south. As the boot is intact and my car has less than 50K on it, I am at a loss as to how this happened.

Given her decades of experience with Firestone, my lovely wife says she knows an outfit that can rebuild it. How I am not sure, as I understand the outer joint externals are welded together.

Thoughts and assistance are welcome.

Speedtoys

" I am at a loss as to how this happened."

Things wear.

50k miles
37 years old

Mrmerlin

just order a new half shaft

Speedtoys

..and change both. Just one of those things where driveline noises move around a lot, can be hard to absolutely nail down...and then you know both 37yr old shafts are new.

Jerry Feather

Whew! Dodged the Wheel Bearing Bullet!