Diagnosing a new rear-end "popping" noise

[sapote]

Well, I couldn't resist taking a quick look since the car was already on jackstands. A little simple green and.... yikes

The cracks or floor seams separation in the photos are still in the early stage, and so I wonder if the squeaking noise could be from other areas that have longer cracks to cause the panels flexing more. I'm interested of what you will find more when the diff/subframe are removed
Listening the video a few more times and it became more clear now that this is a multiple squeaking noise as opposed to a single clunk of the Diff when the torque changed direction.

[Thoglan]

Now I'm worried, I'm pretty sure I've heard a similar noise from the rear end of mine (slight clink or pop under acceleration) and I've had topside and underside reinforcement, already had my wheel arch seams welded once... I had assumed it was an RTAB, guess I'll have to go have a look now :P

[eisen]

Exactly. This is the impetus you needed to bring it to the next level. Pretty much out of your hands at this point. Great looking car. It will only get better when done. Good luck!

Now that's the positivity I need right about now -- cheers!

[Mayan-Viking]

Seriously,
Appreciate everybody for chiming in. I’ll have to evaluate my next steps - was planning to put a half cage in at some point so this might be the time to knock everything out.

Exactly. This is the impetus you needed to bring it to the next level. Pretty much out of your hands at this point. Great looking car. It will only get better when done. Good luck!

[eisen]

Seriously, Vince - can’t believe you pinpointed it just from a short video and some symptoms. Clearly you’ve seen one or two of these! Haha.

Appreciate everybody for chiming in. I’ll have to evaluate my next steps - was planning to put a half cage in at some point so this might be the time to knock everything out.

[Mayan-Viking]

Damn, That sux. Damn, great call Vince.

[eisen]

This is what I was hinting at in my previous post.
My guess would be the panel separation in the left wheel well due to popped spot welds.

Please have a look at these videos for some insight on the underlying issue, where to look for damage, and how the VinceBar kit addresses said design issue:

https://youtube.com/playlist?list=PLg2TArrteKd4ttsu_Nr1SznnEw9N81cN7

Sent from my iPhone using Tapatalk

Well, I couldn't resist taking a quick look since the car was already on jackstands. A little simple green and.... yikes 😬

[eisen]

This is what I was hinting at in my previous post.
My guess would be the panel separation in the left wheel well due to popped spot welds.

Please have a look at these videos for some insight on the underlying issue, where to look for damage, and how the VinceBar kit addresses said design issue:

https://youtube.com/playlist?list=PLg2TArrteKd4ttsu_Nr1SznnEw9N81cN7

Sent from my iPhone using Tapatalk

Thanks, Vince - I appreciate it! I'll queue up the videos tonight and hopefully have some time to give the car a thorough check this weekend. I'll report back with what I find.

[VinceSE2]

It's very hard to tell from a video clip, but to me it sounds like sheet metal panels creaking against each other and popping from one side to another as the load shifts.


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This has also been floating around in the back of my mind and scares me.... The plates were done a long time ago and the bushings done by a shop the previous owner used so I can't be sure how thorough they were. I should probably do an inspection just in case.

Also a guess here, but I assume the subframe was inspected on last bushing replacement? ...but possiblly racp has cracked and it's metal moving around/rubbing on the tear (i know you said plates were installed)

This is what I was hinting at in my previous post.
My guess would be the panel separation in the left wheel well due to popped spot welds.

Please have a look at these videos for some insight on the underlying issue, where to look for damage, and how the VinceBar kit addresses said design issue:

https://youtube.com/playlist?list=PLg2TArrteKd4ttsu_Nr1SznnEw9N81cN7

Sent from my iPhone using Tapatalk

[fattycharged]

Double post

[fattycharged]

Yes, but only to an extent…I've currently two in front of me to compare and one is not like the other


Sent from my iPad using Tapatalk Pro

[bigjae46]

I'd have to lean towards this as well. I doubt I can recreate this exact sound with the diff on the ground, but mine has a lot of play and creates that "TINK" noise with the change in fwd/reverse load even when loading it by hand

That is normal. The ring and pinion gear in the diff has lash or play.

[fattycharged]

From the symptom, I don't think bad CV joint as the noise should be there after rolling but continue acceleration.

Noise when acc from stop and during rapid throttle lifting is the sign of Diff clunk as the torque reverse direction previous moment (decelerate to stop then accelerate, and acc before lifting throttle).

I'd have to lean towards this as well. I doubt I can recreate this exact sound with the diff on the ground, but mine has a lot of play and creates that "TINK" noise with the change in fwd/reverse load even when loading it by hand

[fattycharged]

Check your diff bushings, at your mileage, I'm going to guess they are shot. They just disintegrate.

EDIT: re-read your post, maybe this isn't the issue, but I'd check anyway.

on this note, I learned I have actually been running the e36 bushings for a loooong time now, easily 60k+ miles and didn't notice till I just dropped the diff. They look great btw, no cracking of the rubber, seem to have close to the same deflection as the new set I was planning on pressing in and trying them out....so FWIW I wouldn't hesitate to run them again and plan on it.

[eisen]

From the symptom, I don't think bad CV joint as the noise should be there after rolling but continue acceleration.

Noise when acc from stop and during rapid throttle lifting is the sign of Diff clunk as the torque reverse direction previous moment (decelerate to stop then accelerate, and acc before lifting throttle).

Thanks sapote - that's what throws me off too. I know next to nothing about diff internals (much less how to add shims), but I'll do some more research. As it's a new noise, could it just be part of the diff "breaking in"?