My car is about to shake itself apart!

[jkoebel]

I went on a relatively long drive today to go mountain biking in Plant City, from Orlando.

Coming down the Interstate (I-4 Westbound), I started to feel and hear an odd vibration coming from the differential area. I pulled off, peered under the car and didn't see anything amiss. Flex disk looked good, nothing leaking from anywhere, no holes in anything that I could see at first glance.

The noise was worst at high speed. If I let off the throttle and coasted, the noise went away entirely even if coasting at 60 mph.

As I continued driving another 100 miles, the noise got louder, became a much more noted vibration, and started moving downwards in speed. In lower speeds, 20-40 mph, it sounded like a squealing hinge or door or bearing or something.

The noise continued growing louder and a rhythmic thumping was introduced on the 100 mile return journey.

On the last leg of my trip back to my apartment from dropping everyone off, the noise sounded like BAM BAM BAM and my right rear wheel area sounded and felt like it was repeatedly being struck by something in time with the wheel rotating.

I crawled under again and other than the rear right half-shaft boot being pretty badly cracked, I don't see anything out of place at all. My rear suspension is pretty bad (sagging springs and probably dubious shocks, the rear sits about 3 inches lower than the front) but there's nothing stuck on the half-shaft that I can see.

What do you guys think, am I right in assuming it's the half-shaft? Or is it something worse?

I'm aware that I probably worsened whatever the problem is by driving hundreds of miles, but I didn't have much of a choice in the matter.

'83 240D Automatic.

edit:

Took it to my indie, replaced CV boots and regreased and we're all good.

[TheDon]

you passed right by me. ( Exit for US-27)

Is the crack superficial or all the way through

[jkoebel]

It looks pretty deep. I didn't poke at it to check, though. It looks to be about as wide as a pencil

[TheDon]

it might have been an existing issue and finally the cv joint failed.try and get it to do it again with someone else driving so you can narrow it down. It's easier to hunt down noises while someone else is driving. you know that whole watching the road thing you have to do while driving is in the way of hunting noise.

[Cr from Texas]

Sounds like what mine did a couple of years ago. I actually had it put on a tow flat bed and brought home the last 80 miles. I doubt you made it worse, it's got the be replaced anyway.

Bad half shaft.
Replaced both on the theory they were the same age and had the same PM history. Saved some labor that way.