Popping noise from passenger side rear axle?

[Updated71]

I’ve never done anything with a rear end outside of changing axle fluid. I’m getting what I’d describe as a popping noise from the rear axle one the passenger side at the wheel. I believe my housing is original to the car but the gear set has been changed at some point. There is also a Wilwood disc brake setup that replaced the original drums. Everything there seems to be in order and tight. Nothing obvious is showing.

If anyone has any suggestions on what I can look for, I’d appreciate it.

The fluid was changed winter of 2022. The noise does not seem to be coming from the center section. 

[Wallington]

When does the noise happen? Over bumps or dips? Under braking? when going through tight turns? Backing up?

[Updated71]

I am going to confirm next dry day we have. My only day for a while and it’s going to rain.

It definitely happens when coming to a stop. I don’t recall hearing it on any turns.  I’ll have to pay attention to that. I have heard it as I accelerated from a stop but this was rare. 

Hoping to get that wheel off and recheck everything for again today.

[firebirdparts]

The brakes might have more ability to pop than other stuff.

[Updated71]

Took the brakes off. Nothing apparent there. Went over every bolt and nothing seems loose. My popping is gone but now I’m left with consistent metal thump thump thump. Not sure if this is what it progressed to or it was there and got progressively worse.  Nothing of note on the wheel and tire. Maybe axle bearing? It does get quieter when I apply the brakes but in my opinion it’s still present.

[scarebird]

How much does the axle shaft move in and out?

[Updated71]

How much does the axle shaft move in and out?

Hoping to check that today or tomorrow. Didn’t think to do so when I had the disc off.

[glenn911]

pinion bearing

[Updated71]

Had a bit to look today. The passenger side axle moves in and out but doesn’t seem excessive I know this isn’t much to go on but I don’t have a dial indicator handy.

I had it in the air with it in drives and could not say I heard the noise. No load so that’s the likely reason. Plus it’s not as quiet as I’d prefer these days.

Any suggestions on how to check the pinion bearing?

[5th T/A]

If you said it only made a popping noise going around a tight corner at low speeds, I would say it maybe it needs the gear oil additive required for a Posi rear end. But you said no noise going around corners.

Out of curiosity have you looked at the U-joints? If worn they can make noise. You might see some rust near the rubber seals on the cups. With the driveshaft removed you can carefully remove the two cups that fit in the differential yoke and see if the bearings are dry. If you pull the drive shaft you can rotate the cups and  move the joints around, they should be smooth in operation.

[81Blackbird]

Get the rear-end in the air put it in neural and spin the wheel by hand.  Grab the drive shaft and see if it has any place in it. 
I need a cigarette.

[Updated71]

Thanks for the suggestions. The driveshaft is aluminum. It’s roughly 3 years old. I did take a look at them but didn’t see anything apparent wrong. Tried by hand to see if there is any play at the u joints.  Nothing.

81 Blackbird…I’ll try that later today.

[70_71_78]

Inner pinion bearing check: Engine off, transmission in park if auto or in gear if manual, (stops drive shaft from turning), lift one rear wheel off the ground while making sure the other is fully planted, (keeps one wheel from turning). Now watch pinion end of the drive shaft carefully while trying to rotate the free wheel in both directions, (doesn't hurt to have someone else turn the wheel). First note that there should be very little range of rotation, a couple of degrees may exist due to the stack up of axle spline clearance, spider gear clearance and ring and pinion clearance. The motion at the input side of the pinion should be a very tiny amount of rotation and maybe an almost imperceptible front to back motion. When new those bearing are set up with a preload so larger amount of motion in those directions, (if the driveshaft rotates some check front U-joint and backlash stackup through transmission, some is normal), or motions in any other direction indicates bad bearings, (or improper installation if recently repaired or installed). I don't like to even attempt to reinstall gears after they have been through bad pinion or other bearing issues and am not sure I would use any other meshed parts after exposure to the metal in the gear lube. I am going through this now with my shop suv and the scarcity of used parts and overall poor condition of the body after 16 years of Wisconsin's winter road salt, I think it's done.
J

[Updated71]

Thank you for the advice!

A neighbor came by the other day and as I spun the drivers wheel, he would see the brake pad on the passenger side move. It did make a tap/pop noise but was very quiet likely due my inability to spin the wheel very fast.

I did pull the cover and then that axle. Found absolutely nothing. Rather clean fluid, no missing splines not teeth, bearing and seal did not show damage.

[Updated71]

Thank you for all of the suggestions. It does appear to be a brand issue. Still nothing apparent showing there either. Definitely glad nothing in the rear end.

Hope everyone has a great 4th.