Rear Axle Noise - video included

[69 Rustang]

The rear axle in my ‘72 makes a clicking noise.  I tried to fix it years ago and pulled the center section—didn’t see anything wrong, changed the axle bearing (I am certain it was the left one, but it was a long time ago).  As you can see in the video, when I turn the left axle it is really loud.  The right side, not so much.  At this point I plan on pulling the diff out again and taking it somewhere.  It needs a new pinion seal anyway.  The original is a 2.75 or so open 9” carrier.  I do have another 9” center section, but the ratio is different at 3.25 and I would rather keep it stock.

Any experienced thoughts on what you hear?


View attachment 18F219E3-8D9F-450A-9214-8A16A21FC69A.MOV

 

[Fabrice]

Always tough to guess with sound only and no feel...

Don't you have any play if you try go up/down? Sounds as if the axle bearing behind the hub is done. Bits too clear sound (at least on recording) to be in middle.
You're just 4 bolts and a good pull away to find out, the axle has to come out anyway!

 

[Kilgon]

The rear axle in my ‘72 makes a clicking noise.  I tried to fix it years ago and pulled the center section—didn’t see anything wrong, changed the axle bearing (I am certain it was the left one, but it was a long time ago).  As you can see in the video, when I turn the left axle it is really loud.  The right side, not so much.  At this point I plan on pulling the diff out again and taking it somewhere.  It needs a new pinion seal anyway.  The original is a 2.75 or so open 9” carrier.  I do have another 9” center section, but the ratio is different at 3.25 and I would rather keep it stock.

Any experienced thoughts on what you hear?

View attachment 54220

Your link to the file is not working.  I would also agree with Fabrice in that it would only take a short time to pull the axles  and check the bearings.  Also, have you at least pulled your brake drums to see if something came loose or is broken there.   

 

[69 Rustang]

UPDATE:  my son helped me pull the axles tonight.  The bearings felt great and as I suspected, the left one looks brand new (the pressed on retaining ring is a slightly different color than the other side.  So we dropped the center section out next, then shoved an axle into the center section and turned it: click click click click…. Then we got the spare 9” center section out and tried that one…guess what…click click click click!  I had my son turn the axle while I used a flashlight to look at the spider gears and I couldn’t really see anything wrong.  No metal in the housing, it all looks good.  I think I am going to take the center section to a driveline shop and have someone look at it, I don’t recall any 9” doing this and I have 2 of them that do.  The clicking is only on the drivers side.

 

[69 Rustang]

The verdict:  worn bearings and internal carrier damage.  Need to replace the carrier and install new bearings.  Hope to have pictures in a few days of the damaged bits.

 

[Fabrice]

That's some bad & $$$ news...
How do you think this happen? Wrong or not enough oil? These bearings are not weak pieces usually.

 

[69 Rustang]

I learned this is not the original center section to this car—this one doesn’t have a fill plug so it was changed somewhere along the way during life for one of the same ratio.  If it was under filled, it happened before I got the car as it always had a clicking noise, but I never bothered with it as I haven’t put that many miles on this car to worry about it.  I did pull it years ago trying to figure it out and put it back—that was when I realized there was no fill plug and I had to fill through the axle tube.  I think I actually overfilled it as it leaked out and ruined the brakes on one side despite new seals.  The guy doing the rear now is swapping out cases for one with a plug for an extra $50.  

The worse news is I have a second 9” center section with 3.50’s that makes the same clicking noise only it sounds even worse than the one I pulled from the car.  So apparently I have two junk center sections!  At least this one will be right when it is done.

 

[Fabrice]

No chances for the second  one to be just the bearing?

For now try see the bright side: One on two is not that bad of a score :O
and you'll soon have it back in ready to roll again!

 

[c9zx]

Sorry for your bad luck but, it sounds like you'll be up and running soon. Chuck

 

[69 Rustang]

A few pictures of the damaged carrier, and a few pictures of the restored differential.  The first picture shows where a thrust washer used to be, it had worn away some time ago left behind is scoring and a huge ridge of worn material.  The second image is the gear that was wearing on the surface in the first picture.  The third picture is the other half of the carrier, notice the wear on the outer ring outside of where the spider gears are—it was grinding along here.  So the noise I heard was because of the play in the spider gear/carrier assembly due to the missing thrust washer.  All in all, I got lucky that my ring gear and pinion gear were not damaged.  

The other noteworthy comment is on the second picture.  The spider gear here has four sections where there are no splines, so the 28 spline axle is only connected to 24 splines in the carrier.  Notice the gap in splines visible at about the 12 o’clock and 3 o’clock positions. The guy doing the work for me said this is very common and almost always present in a 8” rear end, and it is uncommon but sometimes present in a 9”.  He installed gears with the full 28 splines when he put the new one together for me.

The last two pictures are the work of art I am going to install.  Included with the overhaul was a gasket, copper washers, new nuts, and gear oil.  Out the door for $420 including him swapping the differential case for one with a fill plug (which mine did not have due to someone changing it somewhere along the way).

 

[c9zx]

Looking good! Chuck

 

[Kilgon]

Glad to see you got it fixed.  Not to bad of a price considering the labor and parts for it.   

 

[Fabrice]

Amazed at the damage done. Considering all this was bathed in thick oil, I wonder how long it took to get to that point. Especially without noticing any sound.
I agree with Kligon, certainly not a bad price. I'd say that's a very good price.

Glad you'll be rolling soon with no clicks!

 

[69 Rustang]

All back together and first drive tonight—wow, the noise!  Where was it because there wasn’t any!  That is the quietest rear end I have ever had in a Mustang.  Whew, glad that’s done.  

Now its time to get the interior put together!