Help diagnosing on throttle clunk after rear end refresh

[Nate047]

Gonna get back under there this weekend and check all
of this lol. Front diff mount bolt is high on the suspect list too.

[sapote]

This has been suggested a few times now, how will I know if the joint is toast? Play/slack? Guess I’ll be dropping the exhaust next.

video 2 & 3 look normal so I don't think it's the CV joints. But you can check this way: jack the wheels off ground, then rock one shaft and check for plays on the CV and should have zero.

For the long driveshaft, I think you can see the CV at the end of the heat-shield.

[fattycharged]

Did you grease the cv before you put it all back together?

[Nate047]

Driveshaft CV joint ?


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This has been suggested a few times now, how will I know if the joint is toast? Play/slack? Guess I’ll be dropping the exhaust next.

[Stilt]

Driveshaft CV joint ?


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[COVID-19]

Back when I did mine the M clunk increased when I went from oem to poly bushings.

[Nate047]

Could be just an old LSD with clunk. Place the camera under the diff then drive forward/backward to see if the diff moves too much. To verify if the diff really clunks: repeat the same drive as in 1st video but press the clutch pedal before let off the gas during slow down to avoid engine braking. If no clunk then I think it's the diff clutch slips and spiders hitting side gears clunk.

I’m sending the car away tomorrow for something unrelated, but when it’s back I will throw a GoPro under there. Good call.

[Nate047]

I did that, the clunking sounds are definitely originating from the diff/driveshaft. Checked what I can access without dropping the exhaust, all is tight. FWIW it’s not that bad or loud sounding under the car, it’s worse in the cabin while driving…

[sapote]

Could be just an old LSD with clunk. Place the camera under the diff then drive forward/backward to see if the diff moves too much. To verify if the diff really clunks: repeat the same drive as in 1st video but press the clutch pedal before let off the gas during slow down to avoid engine braking. If no clunk then I think it's the diff clutch slips and spiders hitting side gears clunk.

[mrgizmo04]

2nd and 3rd video look OK to me. 1st video almost sounds like the standard creaking/squeaking from poly to me...

Put it on jackstands and have someone put it in gear and see what is happening underneath and where exactly the sound is coming from.

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[Nate047]

Hey guys, I posted a few things about this in other threads, but I’m officially calling for help now.

Trying to diagnose some exaggerated on throttle clunking after a rear end and subframe refresh. The car is a work in progress and has solid CMP subframe mounts, PowerFlex front differential mount, ECS poly rear differential mounts. Rear wheel bearings are brand new.

I’m checking everything and I have not found anything loose underneath. I have not dropped the exhaust to check the driveshaft center but I know I torqued that stuff. I do have the rear interior removed, which I know contributes to NVH. However, I feel like this sound is maybe not just the poly diff mounts doing the thing they do.

First video is low speed driving around my neighborhood, you can hear the clunking as I go on it off throttle. Second and third videos are showing the amount of play and sounds I can hear when I’m under the car and moving the hubs around. Is this amount of play and these sounds normal? I feel like I might be missing something obvious and I could really use some help!

https://www.dropbox.com/scl/fi/myqqnybbfgaxx2598237s/IMG_1495.MOV?rlkey=6alx4240623b1s3x9nqcjaxjs&dl=0

https://www.dropbox.com/scl/fi/3bg39jfeak7euzo5zr21s/IMG_1541.MOV?rlkey=gvplcii61wrdi6h3adux0062j&dl=0

https://www.dropbox.com/scl/fi/duu5lfoi4px6mljcp7jzx/IMG_1542.MOV?rlkey=8zh5w9m9tz6d8nws2vw096wau&dl=0