Funny new noise from rear on Pearl ( 72 -450)

[meltedpanda]

Been nice so been running Pearl about , top up of course.
Last few days sounds from rear that sound like gears grinding, I am sure it is in the rear, but cannot localize, other than Differential , what else is there??

[Graham]

Originally Posted by meltedpanda

Been nice so been running Pearl about , top up of course.
Last few days sounds from rear that sound like gears grinding, I am sure it is in the rear, but cannot localize, other than Differential , what else is there??

You might first check your flex disks and the mid shaft bearing because these things can be dangerous if the fail. Hard to see it, but I got good pic by shooting blindly with my little Canon!

Other possibilities
- Brake caliper sticking
- sway bar link undone and leaning against a rotating part.
- diff or axle bearings (hope not)

If it's the diff, you might be able to tell by jacking car up and running car in gear.

BTW - I once was sure I had a noise from rear and it turned out to be front wheel bearing! And another time, I was sure front brake was binding and it turned out to be rear! Keep an open mind

[meltedpanda]

thanks , I will back her up on some ramps, It has a fairly new ( old) diff from the previous rebuild , so I am leaning away from that. The sound comes and goes, so I will check all you mention. I'll park her for now and find some time to investigate. I will et you know what I find. I know how to check flex disc , not sure about mid shaft bearing, would it just be loose?

[have mercy]

Have you greased all fitting [center bearing]. there should be a littleback lash, jack up 1 side of the rear move tire back and forth , lission for noise. then do it to other side. also with car on stands grab a hold of drive shaff see if there is any play.

[meltedpanda]

no have not , sounds like that is where I will start - thanks

[meltedpanda]

well got her up today , one wheel at a time and could not reproduce noise that way. The flex discs look good front and back. It was hard to visualize the center carrier bearing but I could not get it to make noise there either.
HOWEVER ,got in the car accelerating - no noise, let off gas and starting around 30 to stop a definite gear type sound, remians if I am in drive or nuetral , about 90% sure it is not related to brakes. I did isolate to passeger side, midship and back, that is as far as I got with the light I had. This one is strange, my gut tells me it may be carrier center bearing , I could not see it well , and I did not see a grease fitting, looks like I would have to drop the muffler pipes to get to the access hole. Its not the rear diff.
I may have to take it where i can put it on a lift and run her up to speed and back. Any other suggestions?
Classic signs of bad center bearing are...?
Old cars , gotta love em...

[Graham]

Originally Posted by meltedpanda

Classic signs of bad center bearing are...?
Old cars , gotta love em...

When I had that bearing go on my 300D, it made a roaring sound that vibrated through the entire car. It did this at certain speeds only - forget exactly, but something like 35-55mph. Definitely not a gear sound.

There is no grease fitting on that bearing. It is just an skf ballrace that sits in a rubber housing. If you have a digital camera, you can hold it through the opening just behind the tranny and get a picture. Too bad I am not closer by - I bought one of those video snakes that lets you see around corners.

It could also be that the noise is from a universal joint. There is also a spline sliding joint that possibly could be loose? And two centering sleeves. This diagram may help, but the driveshaft is covered in section 41 of chassis manual:

[meltedpanda]

wish you did too Graham, I think we could get along well!
I think I will see if I can get her up on a rack

[meltedpanda]

Ok the noise disappeared for most of the summer, now cold and its back , only noticible on deceleration in gear , if I put it into neutral the noise dissapears. back in and it returns, but as before not always there. Definetly from the rear and sound like a card on bicycle spokes. This is strange ......

[nobby]

Only going straight? Only in turns?

Do you have a speedo cable?

Center prop shaft bearing will set the whole car shaking at certain speeds.

[meltedpanda]

straight or turns, but mostly straight, always on deceleration.
Im leaning to the center shaft bearing. I put her up today on rack and could not reproduce it in the air. I did grab hold of drive shaft and felt some play , not sure that is normal , but felt like the play was in the center area , not by the differential

[meltedpanda]

up on racks, carrier brearing looks good, nothing else loose, nothing , nothing I could see, one sway bar link is pretty trashed , could that make this noise???

no sound with moving of wheels

[meltedpanda]

it is worse , decelerating up a hill and in 3 as opposed to drive ( its an auto)
if that means anything, which right now I am clueless. The guy that had it up on his rack is quite experienced in wrenching , he was scratching his head as well

[rowdie]

Clicking noise sounds like maybe one of the rear axle joints or maybe like Nobby suggested on the speedo cable. Is the speedo erratic. How about the axle boots on each side. Any signs of cracking or leaking? They are not CV joints like on U.S. cars of the 80s the noise sounds like that.

[meltedpanda]

speedo cable is good, speedo is smooth, the axle boots are in tact and appear new(ish), no play , no slop,
I guess I could peel em back for a better look