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Strange "W" sounds at speed
https://slantsix.org/forum/viewtopic.php?t=6328		 Page 1 of 2
Author:  Paul [ Sat Jul 19, 2003 11:52 am ]
Post subject:  Strange "W" sounds at speed
I've owned a stock 1965 Dart 170 (trim level) 2 door sedan for the last 17 years. It currently has 204,000 miles on it. It is a slant 6 with 904 automatic and manual everything else. I love the Ruby Red metalic color (TT1 T paint code).

Its making some driveline/rear end noise that keeps me from driving it except around town. I would describe it as a big WW sound, at first it only happened above 65mph, but over time the starting speed has been dropping - its starts around 50mph anymore. Frequently, the sound gets briefly worse (with some vibration) if I release the throttle over 55mph. Over 60mph the sound overpowers the radio (well, I could crank the AM, but why?). It is accompanied with some vibration starting over 60mph, below that its just an annoying sound. Turning or breaking seem to have no effect on the racket, though I don't do much of either over 60mph.

My first thought was the ball and trunion was bad, letting the driveshaft flop around a bit. The boot broke near the small end at about 180,000 miles. So I pulled the driveshaft out and did find the rear u-joint was going again (bearings breaking, but not yet scaring up the cross or cups). The B&T seems to be fine. I tested it by spiking the other end into my lawn and then twisting the B&T and sliding it up and down. It feels real smooth and tight, plus I can hear the grease inside. I think the claning in my driveline (rolling backwards slowly, drop into drive) is just the output splines of the 904 automatic which have quite noticeable play. I know if I smash the throttle at lower speeds next to a cement wall I can hear some clicking at times, kinda why my first thought was the driveshaft.

Any ideas on what is really wrong? Can a stock driveshaft go out of ballance? Can the B&T feel good by hand and be trash inside? Does this sound more like the rear axle bearings? Thanx for the help, 'cause this car has been so reliable that I don't know alot about diagnosing problems.

Paul G.
Author:  Dennis Weaver [ Sat Jul 19, 2003 12:34 pm ]
Post subject: 
Could be your rear wheel bearings, but my money's on the carrier bearings.

"DW"
Author:  slantzilla [ Sat Jul 19, 2003 3:54 pm ]
Post subject: 
I'd pull the axles and look at the wheel bearings. :shock:
Author:  Doctor Dodge [ Sat Jul 19, 2003 10:32 pm ]
Post subject: 
Is the gear oil up to level in the rearend?
Has the cover ever been off the rearend?
You may want to get a gasket and some new gear lube and pull the cover for a look.
DD
Author:  Paul [ Sat Jul 19, 2003 11:44 pm ]
Post subject:  RE: strange W sounds
Wow, this list is quick with responces!

The rear cover has been off, at about 160,000 miles. It was done by a reputable local shop when the front seal was also replaced - that didn't look like a job I wanted.

I will check the oil level again, once I get the driveshaft back in and the rear level. However, it has not been a problem on previous checks and no leakage is evident. The problem has been creaping up on me for about 4 years. The front seal and gear oil change was about 8 years ago.

I'm not at all sure what is inside a rear end, but the whole idea of bad carrier bearings doesn't sound good. Any good sources for the B&T boot?

Thanx,
Paul G.
Author:  bud L. [ Sun Jul 20, 2003 9:29 am ]
Post subject:  ?
After you've confirmed the rear axle has the correct lube level, and the axle bearings are good and greased sufficiently, make sure the pinion nut hasn't backed off.
Author:  Paul [ Sun Jul 20, 2003 2:48 pm ]
Post subject:  RE: strange W sounds
I have confirmed that there is oil in the rear axle. Right full and looks good.

The pinion nut is tight as far as I could determine. That is to say I can't budge it with my 3/8 inch rachet and 1 1/8 inch socket. I'm not really sure how this nut is supposed to be properly tightened, I set the parking brake and had at it. I did notice that there is a little play in the input, and with my wrench pushing on the nut I could get a little clunk.

Axle bearing greased?? I've never been past the backing plates, but thought they where running in the gear oil. I would bet they have all 204,000 miles on them and if they are greased that would not be good (I could dig through the folder full of reciepts to know for sure). Both rear wheels have a little in and out play, not much but I can feel it with the tires on the car (perhaps 30 thou). Can't feel anything by rotating them in the air, slight brake drag, spins smooth.

Any tips on how to tell a carrier bearing from an axle bearing?

You people are great,
Paul G.
- in Everett WA
Author:  Jopapa [ Sun Jul 20, 2003 4:31 pm ]
Post subject: 
Hey Paul where in Everett do you live? The Dart I'm working on is up north about 14th Ave. I'll likely have to rebuild the axle also (got a real chunky sounding growl/grind at 35MPH and over) and if I can time it right and you also have to do yours, perhaps we could do both on the same day so we can help each other out.

I'll even provide a 6 pack. You like Henry's? :D
Author:  slantzilla [ Sun Jul 20, 2003 5:02 pm ]
Post subject: 
The axle bearings in my 7-1/4 were sealed ball bearings. :shock:
Author:  bud L. [ Sun Jul 20, 2003 6:55 pm ]
Post subject:  ?
you're probably right, Dennis. I've never worked much on 7 1/4's, I usually swapped them out for bigger rear axles.
If you have much rotational slop in the pinion, and it doesn't move in or out, or up and down, it could mean excessive backlash.
Author:  Dennis Weaver [ Sun Jul 20, 2003 10:37 pm ]
Post subject: 
With the 7.25, sometimes it's easier just to find another cheap complete rear end and swap the whole thing.

I usually swap in some axles with known good bearings to troubleshoot if I've pulled the axles and the bearing(s) is not obviously shot. I realize that you may not have the luxury of having a stack of 7.25 rearends, though ;)

Usually side loading a bad axle bearing (swerving, going through a curve, e.g.) changes the level or quality of the sound, but a bad carrier bearing should stay constant under those conditions.

"DW"
Author:  Charrlie_S [ Wed Jul 23, 2003 5:21 am ]
Post subject: 
To check the B&T joint, try this. Unbolt the joint from the trans. Iinstall two or three flat washers on each stud, and reinstall the shaft. This positions the rollers and shoes in a different position in the housing, where there is no wear. If the vibration goes away, the B&T is the problem, and needs to be replaced. If that is neccessary, I recommend converting to a spicer joint. Do not leave the washers on the studs, that is just a test method.
Author:  Jopapa [ Wed Jul 23, 2003 10:00 am ]
Post subject: 
Quote:
To check the B&T joint, try this. Unbolt the joint from the trans. Iinstall two or three flat washers on each stud, and reinstall the shaft. This positions the rollers and shoes in a different position in the housing, where there is no wear. If the vibration goes away, the B&T is the problem, and needs to be replaced. If that is neccessary, I recommend converting to a spicer joint. Do not leave the washers on the studs, that is just a test method.
This is a silly question, but what are B&T joints? :oops:
Author:  Dennis Weaver [ Wed Jul 23, 2003 10:39 am ]
Post subject: 
Ball and trunion joint. This preceded the crosshaft type u-joint and output shaft slip-spline at the front of the driveshaft to take up fore and aft movement on the early-to-mid-sixties cars and earlier... That is why the older trans have a flanged output. Good question.

"DW"
Author:  Paul [ Wed Jul 23, 2003 3:16 pm ]
Post subject:  Strange sounds gone!
Boy do I feel silly :oops:

The front B&T, though the boot is broken, is in very good shape. I greased it up (without disassembly) and will let it slide for now. Shops around here don't seem to want to rebuild it.

The source of all the noise was the rear universal joint. I'm not sure how, its only been in there 1/2 as long as the original one and was greaseable. The seals where good, the cups turned nicely, and when taken apart only a few needle bearing in each cup where broken. I've seen U joints chirp or grind (and get to the point where the cups don't come off politely). But never such low pitch noises, and the old one turned so nicely. I put the driveshaft in yesterday, but didn't know if the problem was fixed until I could get some speed on the freeway this morning.

On the bright side, I've learned a new failure mode for U joints :)

Paul G.
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