Rear end whine after LCAs, 3rd link, panhard, and aluminum DS
10-26-2011, 08:35 AM
#12
Yeah, I meant stock 5.0s.
Anyway, I didn't have time yesterday to loosen up the LCAs to see if that would affect the whine at all. Only had time to adjust the panhard and align the rear end to the driver's side about 1/4" or so.
I took a ride with a buddy in his 2011 5.0, and his whine was barely audible relative to my car (he even had his back seat out). He has the same Steeda 3rd link, but a different brand of LCAs (BMR?) and a stock panhard bar. So that should just about rule out the 3rd link, unless my rear just has more whine to it, they're all different.
My club (NVMC) has a private drag racing event this Sat, so I'm not going to mess with anything else until after. I should be able to get dozens of runs, woot!
Anyway, I didn't have time yesterday to loosen up the LCAs to see if that would affect the whine at all. Only had time to adjust the panhard and align the rear end to the driver's side about 1/4" or so.
I took a ride with a buddy in his 2011 5.0, and his whine was barely audible relative to my car (he even had his back seat out). He has the same Steeda 3rd link, but a different brand of LCAs (BMR?) and a stock panhard bar. So that should just about rule out the 3rd link, unless my rear just has more whine to it, they're all different.
My club (NVMC) has a private drag racing event this Sat, so I'm not going to mess with anything else until after. I should be able to get dozens of runs, woot!
10-26-2011, 08:47 AM
#13
2nd Gear Member
Join Date: May 2008
Location: OH
Posts: 317
10-28-2011, 09:24 AM
#15
Yes, the DS came with CV joints on both ends. Anything's possible, but the whine is only heard upon deceleration while in gear -- would that point to the driveshaft? While accelerating, there's no whine and no noise coming from the rear. It really sounds like the rear end is connected to the chassis of the car via some metal, and the sounds I hear are being transmitted via that link and not dampened properly like when I had the stock parts in there with the soft rubber bushings.
The DS came with a new pinion flange, but can't see how we could have messed that up -- we removed the pinion nut, pulled off the old flange, installed the new flange, tightened the nut all the way, then backed it off, applied thread locker, and finally torqued to ~ 140 ft-lbs.
I'll double-check the pinion flange/rear end angle versus the transmission angle to make sure they're parallel -- I read somewhere they should be the same angle, usually parallel with the ground. So either the angles are off, or something was over-tightened, or the gears are just noisy during in-gear deceleration. I need to spend some more time under my car
The DS came with a new pinion flange, but can't see how we could have messed that up -- we removed the pinion nut, pulled off the old flange, installed the new flange, tightened the nut all the way, then backed it off, applied thread locker, and finally torqued to ~ 140 ft-lbs.
I'll double-check the pinion flange/rear end angle versus the transmission angle to make sure they're parallel -- I read somewhere they should be the same angle, usually parallel with the ground. So either the angles are off, or something was over-tightened, or the gears are just noisy during in-gear deceleration. I need to spend some more time under my car
10-29-2011, 01:24 AM
#16
Join Date: Aug 2011
Location: Michigan
Posts: 21
that should be good.. i just saw a 2013 boss prototype carbon DS today.. what I saw was a one piece with a CV on either end, no clue if its for production or not but your setup with 2 cv should keep it quiet and smooth. fyi that same boss also had 15" brembo's with 2 piece rotors! it was leather bra clad to the max.
is your rear diff OK? do you have any fluid leaking? as i said before my car makes crazy whine noises since i put that steeda shifter bracket on there.
is your rear diff OK? do you have any fluid leaking? as i said before my car makes crazy whine noises since i put that steeda shifter bracket on there.
Yes, the DS came with CV joints on both ends. Anything's possible, but the whine is only heard upon deceleration while in gear -- would that point to the driveshaft? While accelerating, there's no whine and no noise coming from the rear. It really sounds like the rear end is connected to the chassis of the car via some metal, and the sounds I hear are being transmitted via that link and not dampened properly like when I had the stock parts in there with the soft rubber bushings.
The DS came with a new pinion flange, but can't see how we could have messed that up -- we removed the pinion nut, pulled off the old flange, installed the new flange, tightened the nut all the way, then backed it off, applied thread locker, and finally torqued to ~ 140 ft-lbs.
I'll double-check the pinion flange/rear end angle versus the transmission angle to make sure they're parallel -- I read somewhere they should be the same angle, usually parallel with the ground. So either the angles are off, or something was over-tightened, or the gears are just noisy during in-gear deceleration. I need to spend some more time under my car
The DS came with a new pinion flange, but can't see how we could have messed that up -- we removed the pinion nut, pulled off the old flange, installed the new flange, tightened the nut all the way, then backed it off, applied thread locker, and finally torqued to ~ 140 ft-lbs.
I'll double-check the pinion flange/rear end angle versus the transmission angle to make sure they're parallel -- I read somewhere they should be the same angle, usually parallel with the ground. So either the angles are off, or something was over-tightened, or the gears are just noisy during in-gear deceleration. I need to spend some more time under my car
10-30-2011, 10:59 AM
#17
There is some gear oil on the driver's side axle around the vent thingie -- not enough to drip onto the ground, but enough to be visible on the axle. I thought this was normal since we did tilt the rear up before removing the OE pinion flange to make sure we didn't spill anything. Other than that, no leaks. We thought this was normal so I didn't mention it before...
Cold weather hit, snowed yesterday here in VA and drag racing was cancelled. It may be some time until I can get her up on jack stands
Cold weather hit, snowed yesterday here in VA and drag racing was cancelled. It may be some time until I can get her up on jack stands
11-11-2011, 03:25 PM
#18
Join Date: Sep 2011
Location: Illinois
Posts: 1
Don't know if the newer rear ends still use a crush collar between the pinon bearing and the housing if thats the case removing and reistalling the pinon nut theres a chance the backlash changed between the ring and pinon and thats why you now have a noise.Backlash needs to be checked with a dial indacator.
11-14-2011, 01:21 PM
#19
I'm starting to lean toward my driveshaft as being the cause of the noise. I really need to get under my car and check the angles, should have time later this week or next week, taking some time off from work.
11-16-2011, 06:59 PM
#20
Former Sponsor
Join Date: Sep 2007
Posts: 1,936
Likely answer... all of it is adding some noise, totaling the noise you have.
Think this through. You now have boxed or tubular arms that act as sound tubes. You have much harder bushings or joints than the stock rubber that sucked up some noise and vibration. You have a longer, lighter driveshaft that no longer has the carrier bearing in the middle to damp vibration. Honestly IMHO the least likely culprit is the UCA, but still being bolted to the axle and body it's contributing as well.
I don't know what you are really doing with the car, but from a performance standpoint the driveshaft would be something I'd want to keep more than LCA's most of the time. Kind of depends on how much wheelhop you had to start with, some are bad, others aren't at all.
Solution: Start swapping out parts for stock to see what doesn't annoy you. Depending on what kind of control arms it's possible we might be able to stay aftermarket but have less racket (like billet lowers instead of tubular or boxed ones, as that helps with noise a bit).
Think this through. You now have boxed or tubular arms that act as sound tubes. You have much harder bushings or joints than the stock rubber that sucked up some noise and vibration. You have a longer, lighter driveshaft that no longer has the carrier bearing in the middle to damp vibration. Honestly IMHO the least likely culprit is the UCA, but still being bolted to the axle and body it's contributing as well.
I don't know what you are really doing with the car, but from a performance standpoint the driveshaft would be something I'd want to keep more than LCA's most of the time. Kind of depends on how much wheelhop you had to start with, some are bad, others aren't at all.
Solution: Start swapping out parts for stock to see what doesn't annoy you. Depending on what kind of control arms it's possible we might be able to stay aftermarket but have less racket (like billet lowers instead of tubular or boxed ones, as that helps with noise a bit).