Rubbing noise from differential/transmission area

[RichardA]

I have a 1967.5 Datsun 1600. Today, I heard an low sounding rumbling sound from the differential area when in gear at very low speed on level surface. It almost felt as if I the emergency brake was on (but it wasn’t)
No such noise when in reverse or driving up incline. Any thoughts as to the cause?
Could this be as simple as needing differential oil or as extensive as a new transmission/differential?

Thanks!!
Richard

[Nissanman]

If you have never attended to the diff oil or drive line uni joints, perhaps they are to blame.
All you can do is inspect and lubricate/replace each item as you go.
Leave the most expensive option, gearbox and diff removal until all other sources are serviced

[RichardA]

Thank you very much!!

[redroadster]

Axle bearing comes to mind or carrier B.
If it's constant noise & doesn't change much braking on vehicles setting for long periods and outside the upper part of the bearing can loose all lube and collect moisture with changing Temps
You know what noise a U joint going out makes right ?

[Bwk2000]

To narrow it down, try these steps:

1. Let the car roll down a small hill (engine off, in neutral, foot off the brake). Now repeat it with your foot gently on the brakes going down hill. If the noise is gone in BOTH tests, problem is likely in your transmission. If the noise comes back ONLY when lightly touching the brakes - well, it’s your brakes
2. If the noise is still present in both tests above, jack up BOTH of the rear tires (car on jackstands, in neutral, emergency brake off) and take turns spinning each wheel quickly in a forward motion direction. Is the “rumbling” noise (aka grinding) louder on one side of the car or does it sound about the same from both sides? If it’s about the same on both sides, it’s likely a carrier bearing or gear. If its noticeably louder on one side, it’s likely the axle bearing on that side.

P.S. Make sure your emergency brake is not sticking first - Seriously, it could be that simple.

[jrusso07]

I had a similar noise on my 70 running aftermarket wheels, just at low speed. I pulled the rear wheels and found the rear drum on the driver side wasn't seated. Reseated it and torqued down the wheel lugs and no more noise. I am not sure how it came unseated but the rear lugs were looser than on the passenger side. May have been movement typical of aluminum wheels. Tire shops want us to retorque lugs after 100 miles

[Bwk2000]

… I pulled the rear wheels and found the rear drum on the driver side wasn't seated … I am not sure how it came unseated but the rear lugs were looser than on the passenger side …

That must have been a bit disconcerting … especially if you were doing a lot of highway driving.

[Gregs672000]

To narrow it down, try these steps:

1. Let the car roll down a small hill (engine off, in neutral, foot off the brake). Now repeat it with your foot gently on the brakes going down hill. If the noise is gone in BOTH tests, problem is likely in your transmission. If the noise comes back ONLY when lightly touching the brakes - well, it’s your brakes
2. If the noise is still present in both tests above, jack up BOTH of the rear tires (car on jackstands, in neutral, emergency brake off) and take turns spinning each wheel quickly in a forward motion direction. Is the “rumbling” noise (aka grinding) louder on one side of the car or does it sound about the same from both sides? If it’s about the same on both sides, it’s likely a carrier bearing or gear. If its noticeably louder on one side, it’s likely the axle bearing on that side.

P.S. Make sure your emergency brake is not sticking first - Seriously, it could be that simple.

Really nice and useful info here... well done.

[spyder]

I had a rear outer bearing go bad. It made a swoosh swoosh noise. Perhaps you could elevate thje rear end and take off the tires than listen. Wiggle the axles for loosness.

[jrusso07]

… I pulled the rear wheels and found the rear drum on the driver side wasn't seated … I am not sure how it came unseated but the rear lugs were looser than on the passenger side …

That must have been a bit disconcerting … especially if you were doing a lot of highway driving.

When I first heard the noise, I was less than a mile from my house. I turned right around and pulled the rear wheels and found the loose drum.