Rattling noise coming from rear end

[JDBronco77]

I’m trying to figure out what this noise is. I got off the freeway, and then started hearing this awful noise. I’ll take a look at it tomorrow, I didn’t have time today after limping it home at 5mph. From what I’ve seen, it could be the rear drum brake, something broke or went loose. Maybe transfer case as well, I’m hoping not. I’ll have more info tomorrow, but what’s your initial thoughts?

 

[DirtDonk]

You’re right, sounds great! :-(
Welcome to Classic JD. Good video. Sorry to hear your having trouble.
Lots of other noises too (I hope), but pretty good video of the sound nonetheless. Can’t say I’ve heard one just like it before, but a lot of odd noises seem to come from the double cardan joint setup.
You’re right that it could be something in the brakes, but it sure sounds loud and deep compared to other times I’ve heard brake stuff.
Any chance it’s something benign, such as a parking brake cable laying down and getting bounced around by the driveshaft?

What transmission are you running?
What transfer case? Could it be a rear output bearing in a transfer case?
What other modifications, such as lift, tire size, axle swaps, and all the usual suspects, etc.?

Good luck. Can’t wait to hear what you find upon closer inspection.

 

[Madgyver]

grab your driveshaft and check if any of the u-joints are compromised. On the CV end, also check if output bearing has any play. May 1st thought is drum brake parts came loose. Process of elimination.

 

[Tiko433]

The good news is the motor sounds awesome. Like mentioned above grab that drive shaft and try to turn it and push on it look at the U joints . Made sure the caps are tight and in place. Then I would jack up the rear put it in neutral and spin the drive shaft. I would like you would find the problem quick

 

[okie4570]

Sadly sounds very similar (same) as when one of the bearing caps came lose in the rear end of my 71', internals became out of tolerances and lost some teeth on the ring gear. Hopefully that's not what it is, but the sound is the same. Happened in the middle of an off road trail, limped out in front wheel drive only until we got to obstacles where I had to winch up because of no rear.

 

[Johnnyb]

I think you start by inspecting the driveshaft and external stuff.
Then take the drums off and see if one of the adjusters is rattling around,
Then see if there is ANY lateral play in the wheel bearings - also run the rear-end on jack stands to see if the noise is apparent.

Good luck!
-JB

 

[JDBronco77]

Still trying to diagnose the issue, it is coming from the rear driver, no play in the drive shaft, or wheel bearings, still haven't checked the bearing caps . I took the wheel off, inspected the drum, everything seems to be in place. I still think its coming from the drum, I'm waiting on a buddy so I can run it on the jack stands. I will keep you updated.

 

[DirtDonk]

Well, not that I've ever heard a rear wheel bearing make anything like your noise, but... Have the rear bearings ever been replaced? They have a finite life expectancy of approximately 100k miles, or 40 years. Hah!
Usually, they quietly die and leave you stranded with a wheel exiting the vehicle at the least opportune moment. Usually on a highway, or towing. Generally 55mph or above (heat buildup) or when hauling a load or towing a trailer. Again, heat buildup.

Since we've talked about them so often over the years here, I thought I'd bring it up just in case.
I know you said that there was no notable play in the axle, so that's a very good sign that the bearing is ok. But you can't be too careful with this part.
If you have never replaced them, or don't know if they have ever been replaced, and your Bronco fits either of the two criteria, it would not be a bad idea to do the extra work to pull the axle out and take a closer look-see.
When I found bad bearings on my '71, they were not making any noise, nor did they have what I thought of as a lot of movement. But when doing the brakes one day, I thought the bearing "sounded" a bit dry. Turned out the little bit of movement I felt was indeed too much!
And this was at just a little over 80k miles, if I remember. Certainly less than 90k.

Just a thought anyway.

Paul

 

[.94 OR]

Outside the box: does the noise change if you engage the transfer case to spin the front driveline? On the older rigs there is often enough drag in the transfer case to turn the front driveline slightly and I'm curious if you have an issue there that could be quickly ruled out.

 

[JDBronco77]

I pulled the driver side axel out, for sure need new bearings. The funny thing was, is when I pulled, pushed, and jiggled it while still attatched, there was very minimal play pushing in and out. I was surprised how bad it was when I pulled it out.

 

[okie4570]

I pulled the driver side axel out, for sure need new bearings. The funny thing was, is when I pulled, pushed, and jiggled it while still attatched, there was very minimal play pushing in and out. I was surprised how bad it was when I pulled it out.

Is that where the noise was coming from while it was up on jack stands?

 

[DirtDonk]

Same minimal play I had probably.
But yes, you have found a completely thrashed, old and tired, worn out, given up the ghost, given good service, wheel bearing.
When you get a new one, you will realize that any play is a bad thing. The bearings themselves have no perceptible play when they are new.
The only In-N-Out movement, you should see when the parts are fully assembled, is sometimes some space between the outer retainer and the outer race of the bearing itself.
But they’re really shouldn’t be any of that either in a perfect world.
No real play in the bearing that you will be able to detect.

And it will be smooth as glass and If you spin it by hand, it will not continue to spin. Instead, it will stop instantly as soon as you release.
Glad you found it. Looks like it’s time to do the other side as well!

And the other good news is, if you didn’t know already, now you will know whether you have a big bearing or a small bearing rear end.

 

[Johnnyb]

When I swapped my stock style axles for wild horses 31 spline, I was very pleased to notice that the bearings have the grease seal outside the bearing surface.
Unlike Ford factory-style bearings where the grease seal is inserted in the axle tube and the bearing itself is sealed.
Though I have few miles on the new bearings at this point, I have every expectation that this is a much better solution then factory style.

-JB

 

[gr8scott]

When I swapped my stock style axles for wild horses 31 spline, I was very pleased to notice that the bearings have the grease seal outside the bearing surface.

Same here. Good 'ol Set 20 tapered bearings.

Tapered Roller Axle Bearing, Set 20

Check out the deal on Tapered Roller Axle Bearing, Set 20 at WILD HORSES 4X4

www.wildhorses4x4.com

 

[DirtDonk]

Don’t get them confused though JD.
While the tapered roller Set-20’s were Ford’s heavy-duty answer for the 9-inch differential, they do not interchange with your sealed ball bearing equipped axle shafts.
The bearing has the same outside diameter as the “large” bearing housing ends, they don’t have the same inside diameter.
So they don’t fit the shaft, no matter what housing you have.
You need new shafts.

 

[JDBronco77]

Thanks for all the help and replies! I do have the big bearing, they arrived today, I replaced both sides. The passenger side had some in and out play. Went and rented a slide hammer and pulley to get the seal out. I haven’t replaced axel bearings before, and it wasn’t too bad! I ordered the rear wilwood brake kit also, I will have to take the axels out again to do it. Had to get my truck back up and running. Anyone have the wilwood rear brake kit? I have disc in the front, drum in the rear currently, my brake shoe is also cracked, I’m glad I ordered the brake kit.