Rear end noise
9/18/21, 10:33 AM
#1
Rear end noise
I have a 2008. GT with 22,000 miles 5 speed manual transmission. As of the last few weeks I have a strange noise coming from the rear diff when the car gets hot. This mainly happens when turning the car left and right, this has my mechanic stumped he has changed the fluids and additives in the rear with no change in the noise. With the research I have done I'm leaning towards the clutches in the rear but with only 22,00 miles that doesn't make sense to me. Anyone have an issue like this ! Help
9/18/21, 11:36 AM
#2
Legacy TMS Member
Welcome to the forums! 
There happens to be a TSB for this issue: https://latemodel.cachefly.net/downl...sb09-20-04.pdf
Basically there's a damper that can be installed to solve this problem, and if it doesn't, then the rear end must be rebuilt, with or without new parts depending.
It's entirely possible that the heating of the components in the back have caused a lash issue with the ring and pinion, and it's just been mis-shimmed from the factory. It's also possible that a rear wheel bearing is not happy and heat is part of that equation, because metal expansion and such, although it'd be worse turning one way than another in that case. Absolutely the clutches in there could be fried, although I'd think it'd be all the time and not temperature related, but what do I know.
And it's a mass produced car, so out of the factory a problem child does escape now and then. It's why they have warranties new.
Perhaps yours is one of those that had it been driven those 22,000 miles in the three (or was it five by then? 
) years of warranty it would have been heard and fixed for free. I mean, they're made to be driven. Not that I'm fussin' about you preserving it like you have (or the previous owners have, if that's the case), but if you don't drive these things strange oddities such as this can occur. And at 1700 miles per year average, the poor thing needs to be driven! I bet it's mint though. Pics! 
I'm not sure what all procedures your mechanic has done to determine anything, but I would get the car warmed up so that it's doing it, then get it immediately on a rack, someone in the car and 'drive' it on the rack. The person below can then absolutely identify where it's coming from, might need a long screwdriver, dowel, or mechanics stethoscope to be sure though. Once found for sure, a proper course of action can be taken. Turning shouldn't be part of the equation for this diagnostic, it's just you can hear it more in a turn when driving. On the rack, that thing should fairly announce itself no matter what.
One last thing: If you've upgraded suspension parts to harder bushings (Poly or hem joints) recently, then that will transmit noises that you won't like. Awesome has a rear end whine at high speed that's directly due to the fact I put in the upper LCA poly poly setup from BMR, as the old factory rubber ones had gone bye bye, and I'd already done the rest of the rear suspension that way. Just finished the job (and dang, that is NOT a job I really liked doin' on the ground... but it's done!) At first I was "WHAT the heck now?!" then I realized what I'd done. She's fine, she's just howlin' in the wind now.
Overall, I'd say if you can't find it... it ain't broke enough. Go drive it until it's obvious, then you can fix it!
Hope that helps in some way! Good luck!
There happens to be a TSB for this issue: https://latemodel.cachefly.net/downl...sb09-20-04.pdf
Basically there's a damper that can be installed to solve this problem, and if it doesn't, then the rear end must be rebuilt, with or without new parts depending.
It's entirely possible that the heating of the components in the back have caused a lash issue with the ring and pinion, and it's just been mis-shimmed from the factory. It's also possible that a rear wheel bearing is not happy and heat is part of that equation, because metal expansion and such, although it'd be worse turning one way than another in that case. Absolutely the clutches in there could be fried, although I'd think it'd be all the time and not temperature related, but what do I know.
And it's a mass produced car, so out of the factory a problem child does escape now and then. It's why they have warranties new.
Perhaps yours is one of those that had it been driven those 22,000 miles in the three (or was it five by then? ) years of warranty it would have been heard and fixed for free. I mean, they're made to be driven. Not that I'm fussin' about you preserving it like you have (or the previous owners have, if that's the case), but if you don't drive these things strange oddities such as this can occur. And at 1700 miles per year average, the poor thing needs to be driven! I bet it's mint though. Pics! I'm not sure what all procedures your mechanic has done to determine anything, but I would get the car warmed up so that it's doing it, then get it immediately on a rack, someone in the car and 'drive' it on the rack. The person below can then absolutely identify where it's coming from, might need a long screwdriver, dowel, or mechanics stethoscope to be sure though. Once found for sure, a proper course of action can be taken. Turning shouldn't be part of the equation for this diagnostic, it's just you can hear it more in a turn when driving. On the rack, that thing should fairly announce itself no matter what.
One last thing: If you've upgraded suspension parts to harder bushings (Poly or hem joints) recently, then that will transmit noises that you won't like. Awesome has a rear end whine at high speed that's directly due to the fact I put in the upper LCA poly poly setup from BMR, as the old factory rubber ones had gone bye bye, and I'd already done the rest of the rear suspension that way. Just finished the job (and dang, that is NOT a job I really liked doin' on the ground... but it's done!) At first I was "WHAT the heck now?!" then I realized what I'd done. She's fine, she's just howlin' in the wind now.
Overall, I'd say if you can't find it... it ain't broke enough. Go drive it until it's obvious, then you can fix it!
Hope that helps in some way! Good luck!
Last edited by houtex; 9/18/21 at 11:39 AM.
The following users liked this post:
acollins (9/18/21)
Thread
Thread Starter
Forum
Replies
Last Post