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8.8 making a odd noise

1K views 14 replies 4 participants last post by  tman1020 
#1 ·
OK I need some opinions. I just switched out my 7.5 rear end on my 06 V6 to a used 2007 GT 8.8 rear end with Limited slip and 3:55 gears.
It is great except for one thing, when I am down shifting hard I get a weird clunk. And then when I apply power after a hard downshift I also get the clunk.
During normal driving or hard acceleration there is no problem whatsoever. Only on a hard aggressive downshift and on the first acceleration there after. Any thoughts???
I did change the pinion flange and it was the first time I ever did this so that could have something to do with it but I'm pretty sure it's tight enough.
All the fluid is brand-new and I used the limited slip additive. I have triple checked the tightness of all the links and shocks. I had no problems before the swap so I'm assuming something in the rear end. Thanks in advance.


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#2 ·
Took it to the local driveshaft and rear end specialist and he really didn't know either. Said maybe the clutches in the Limited slip. I'm wondering if maybe the rubber inside the top link could be slightly worn and making that noise. I did stress it a little bit when I did the axle swap.


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#4 ·
Possibly you did not adjust the new flange correctly. I know of some that got it too tight and it caused problems like clunking right up until it seized.

Did you check to make sure that all the bolts to the driveshaft are properly seated and torqued?
 
#5 ·
Thanks for the reply. Yes I don't think the driveshaft bolts are the problem I removed them and reset them once already. I think it's very likely that pinion flange.
Never swapped one over before so I'm sure I could have either not gotten it tight enough or it's too tight. I would've thought if it was too tight I would've heard a growl though not a clunk. First thing I tried after I realized there was the problem was tightening the flange a bit. I actually put my impact on it and gave it all it had. Still no difference.
Now I'm starting to wonder if maybe my driveshaft could be the culprit. Seems odd though because I had no problems before the swap. Maybe the lower gear ratio was enough to expose an underlying problem with the driveshaft I didn't know I had.
Sure would be nice to figure this one out.


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#6 ·
Not sure which flange you're talking about, hope it wasn't the pinion that you tightened.
Have you checked your UCA bushings...not sure how many miles you have on the car but they do start cracking and splitting and if it does it could cause the rear end to move forward and backward causing a clunking. Also, your LCA's have the OE bushings and are prone to cracking and coming apart. Just a thought.
 
#13 ·
Definitely a possibility. Do you or anyone else Reading this happen to know if it is too tight if it would be causing the trouble I'm describing?

I would have thought it would've been some bearing noise that I heard or some type of a Growl if I got it too tight Very limited info online about this that I can find.




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#15 ·
I visually inspected the rear one. But did not inspect the front one. I didn't have any reason to when I did the swap. But I will definitely check them both out thoroughly.


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---------- Post added at 07:41 PM ---------- Previous post was at 07:40 PM ----------

I visually inspected the rear one. But did not inspect the front one. I didn't have any reason to when I did the swap. But I will definitely check them both out thoroughly.


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Thanks


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