clunk/thump sounds after spl bushings installed
 

i have a question/problem for all the members that has all these spl parts installed on their car..

-spl front lower impact bushing
-spl front lower arm bushing
-spl solid rear diff bushings
-spl rear subframe bushings
-spl FKS rear knuckle monoball bushing set

so i have all these spl bushings installed recently.. and now i have this clunking/thump sound from the rear section.. i never heard these sound before the install.. and yes i know to expect tons of vibrations, squeaking, whining, more chatter from the clutch, etc...but i dont think this is normal..

the clucking/thumping sound happens when i engage the clutch AND release it (usually 1st and 2nd gear.. sometimes 3rd)... it also happens and sounds much louder and rapidly during wheel hop in the rain (i did it on purpose in a empty parking lot to see if that will trigger the clunking/thumping sound ) .. again.. all these sounds comes from the rear section of the car.. and u can feel it when its makes the sound..

dont know if this helps but for the spl sub frame bushing.. i told my mechanic that i want it to be oem spec which on the instruction, it listed 1 big and 1 small shim for the front and no shims for the rear...
but my mechanic told me that they tried that but without the extra shim in the rear.. the subframe will not have contact with the chassie and will leave a gap..
i dont think the sound is caused by the control arm and knuckle bushings..

any help will be appreciated.. i am putting my car on the lift tomorrow to see if everything was tightened up.. and maybe even change the trans and diff fluid..

Just curious you have a 2013 Z why change all the bushings?

You planning to transform your Z to a track car?

I heard the solid diff bushing will cause some of this vibration and clucking sound.

Man with all that suspension upgrade I can feel your Z is solid as a rock and you feel every little bumps?

this is not my daily car.. slowly trying to turn it to a fun track car..
i do expect all these bushings to make unnormal sounds but this just doesnt feel or sound normal to me..

with all these bushings.. its actually not bad at all.. the car still on stock nismo suspension and i dont feel it much harsher driving after the install.. but i can tell u i can hear alot of different sounds from squeaking noise to whining sounds lol

Let as know what you find out what's causing this abnormal sounds. Maybe it needs more drive miles to make everything settle in.

I'm considering of changing my transmission mounts but I would use the Z1 polyurethane one.

For one there's are a lot of plastics/ foams, heat shields that vibrate in the trunk after I switched to coilovers, had to use dynamat to cover all my trunk, heat shield, license plate bracket, stuffed the rear bumper foams with rug towels from vibrating, reinforce my exhaust hangers and bushing.

The price we pay for upgrading our suspension system.:icon17:

But the car handles so good on the twisties. :driving:

i will update this page as what i tried or did to fix this problem..
i have a pair of whiteline poly diff bushings at home but then after i purchase all the other spl solid bushing and motor/trans mounts.. i might as well go all out right? haha so i ended up with the spl solid diff bushings ..
dam and thats just from coilovers? i cant wait to put mine on!

yea i no know lol functional parts aint cheap .. u should see the labor on these bushings.. it cost more than the parts itself lol

I have whitelines sways bars too.. You said it right labor cost is a killer that is why I invested the money instead in buying quality tools little by little and do the job myself or ask fellow members to help for a cost of a pizza and beer!:tup:

IMO suspension upgrades and quality tires are worth the investment rather than doing any engine hp gains. Your in the right direction If you do plan to track your Z.

Sounds normal for solid mounts. That is why I will stay away form them on a street car. Been there, done that before.

i mean i dont mind any of the weird sounds and vibrations as long as its normal.. i just dont want to ignore it incase it is a problem and will damage other parts that will cost me thats all

I have replaced pretty much all my suspension with spl bushing, the diff bushing is Whiteline. I have not done the sub frame bushings though. I had some clucking when going over ruts and bumps in the road. Tony at Fast Intentions checked it out for me while my car was at his shop before ZDayZ. He couldn't find anything wrong so I thought okay one more sound to the other 101 sounds associated with the car. Then I went to ZDayZ and drove the car like I stole it and now I have no more clunking. It may need to be whipped and spurred to get things to settle. I love the upgraded suspension, stock Nismo is not bad at all, but now the suspension is definitely better than its driver.:)

thanks for letting me know! i will drive it like i stole it after i check with my mechanic and inspect everything..
i just did alot of research within the past few hrs and im thinking its either something to do with the driveshaft, differencial, or sub frame bushing spacers.. will update yall in a bit.. heading there now

so i just got my diff and trans fluid flush with red line fluids.. still makes the sounds.. putted the car back on the lift and and started the car and did 1st - 3rd 2500-3500k slow shifts and the sound seems to be coming from between the driveshaft and the transmission... hmm no clue whats wrong at this point.. when they were under the car they said it makes the sound when clutch engages when the shaft stops and go.. also got the solid z1 motor mounts installed and dont no if that have anything to do with it either...

Attachment 105719

its the area that i circled in red that makes the clunk sound

Sounds like the driveshaft may be binding, if the subframe changed height that could have caused it.


The DS input could be hitting the tailshaft under load. Look for marks on either.

My car has been clunky since I got my hp upgrade. It is very noticeable when I leave her in fist, step on the gas then let go. It clunk hard when the drive train is loaded then quickly unloaded. I have stock nismo suspension other than urathane motor mounts and rear diff. The clunk does not feel right to me either.

YzGyz

WOW you went full retard on sound dentoning. I don't notice it until my wife tells me its annoying. But I would rather maintain the weight of my car and deal with the noise than put all that extra weight in.



For OP I sent you a PM back. From what I can tell its possibly the tranny mounts or sub-frame bushings. But now seeing what you have the only other possibility is the tranny mounts. Other manufactures use a bushing in between the tranny and the drive shaft that when torn makes a clunk sound but ours do not have that. So by process of elimination the only to spots are the motor mounts and tranny and you have the motor mounts too. But before you spend more dough, take it into a speed shop and see if their tech has any recommendations. Because to make that clunk noise it has to be a big heavy component between something malleable and a relatively large change. A smaller component with little play would make a rattle noise, vibration.

Is it possible the lock nut on your rear coil over came a little loose?

we checked and there was no signs of anything hitting..

seems we have the same problem.. what brand rear diff bushings are u using.. and did it make the sound before it was installed? update me if u find out anything please

i already had transmission mount installed before any of these and it never made the sound. yea ill probably bring it to a speed shop soon when i have time

still on stock oem suspensions and its tight

I had swapped my rear dif. bushing to Whilelines one. I added my DIY vids. install tot he DIY that was already posted. I never really noticed the minor clunk until after my turbo install. I think It might of always been there but I never noticed it. The other thing is that my clutch/flywheel might play a roll in the clunk too. It has a more on/off engagement than the OEM one. I suspect that this quick loading and unloading of the drive train made the cluck more prominent and noticeable.

Anyhoo, I was just under the car inspecting and trying to figure the cluck out.

It turns out to be a 2mm or 3mm free play of rotation in the drive shaft and rear differential. I held the rear tires still and I manually turned the drive shaft by hand. The drive shaft is able to turn about 2mm or 3mm before it locks in the other direction.

Basically, as you load then unload the drive train, the car will drag (you are off the pedal and friction and the weight of the car will slow) and will make a cluck as the 2mm of free play is used up and the car loads the opposite end of the rear diff. This is like a 1 ton hammer with only 2mm swing tapping the back or front of your car every time you get on and off the gas really fast.

I have the OEM tranny mounts but it's on my to buy and install list.

YzGyz

yes.. i also notice the free play on the drive shaft few days ago when my car was on the lift. but i never heard of it clunk before i had all my bushings and mounts installed..
so is the play and clunk normal? because if it is.. wont everyone will have this sound on their z?
also when my car was on the lift.. the sound came from the where the trans meet the driveshaft area... but when driving it sounds like from the rear..

It appears to be normal to me. It's actually free play in the rear diff itself. I can't do anything about it so I'm leaving it alone.

YzGyz

I have the same issue. I installed the Z1 tranny mount and now hear this clunk and weird noises that sound like it's coming from the diff. Put the car on the lift and there is some play in the diff. I also have a PST CF Driveshaft. So is this play normal in the diff? I also had a shop install some 4.08 gears about 4 years ago. So any info would be great. It's just weird I did not hear it until the tranny mount but the sound is annoying.

My theory is that this clunking was not notice or present until the drive train was stiffened. The 3mm rotational free play was absorbed and dampened by all the OEM rubber. The clucking is more noticeable now that everything is more rigid, transferring the energy and sound to the diver more, hence we now notice it.

YzGyz

the clunk is alot louder and clunks rapidly during wheel hop.. does yours do the same thing too? YzGyz? and usually clunks at lower rpm shifting (under 3500 rpm)?

Im not sure if I missed it, but does it clunk more/louder over bumps? Or only under accel and decel?

doesnt clunk on bumps such as bumpy roads or speed bumps... but it does clunk louder and rapidly during wheel hops.. and clunks when clutch is engaged and released in 1st and 2nd gear on lower rpm and sometimes 3rd gear.. or when pressing throttle and letting go causing that jerking motion..

It's there during wheel hop, and of and on throttle in first gear, and some in second. Again my theory =hop loads and unloads the drive train as tires grip and let go causing clunking.

YzGyz

i wonder does all z has that much play on their driveshaft or we r just the very few that has it..

There is always going to be some play in gears by design or they would not mesh right. But Like everything there is a certain tolerance that I do not know off hand. I'm sure the service man has it. But from what I have noticed it's a lateral clunk and not a rotational clunk. I've also noticed when I let off the gas only in high gears my shifter moves back and forth. Since I have been looking into this more I notice more things as the days pass and my OCD on noises have kicked into high gear. I am a sound analyst so when stuff bothers me I wig out. Hopefully we can solve this together.

Only on load and unload. Bumps and such don't make any abnormal sounds

YzGyz

update! so as for the shifting clunk.. it is not as loud anymore and seems to b normal to make sound when releasing the clutch or pressing the clutch too fast..

the rear sub frame is confirmed by spl that even tho the instruction said 2 shims on the front and 0 shim in the rear for oem spec... 2 shims front and 1 shim rear is ok too and there would not b a problem..

now i have a new problem... front driver side lower rear impact bushing is creaking/squeaking when turning slow or driving slow or coming to stops.. basically when there is load to the front... im sure its the bushing and not the endlinks or sway bar bushings and all the bolts is tight... did anyone grease any of the spl bushings? it started making the sounds after a month of install and its getting louder and louder.. very noticeable..

Does it look like there is movement in the bearing? Like are the surfaces smooth or rough? Could be binding due to a weird angle of force?

I have put some white Lithium on mine in the past, not sure if that is correct or not though.


-Daelen

my mechanic said there is no movement what so ever and everything seems to be tight.. i can probably snap some pics of it this weekend.. not sure what surface you are talking about..
why did u put white lithium on your bushing before? was it making sounds or u just want to put grease in there to prevent sounds?

I got all the SPL solid bushings installed except for the subframe ones. I'm thinking about it as I was told it will become noisy by a good margin.

just got off the phone with mike from spl... great customer service by the way... anyways.. he had suggest that i use use tri-flow superior lubbricant for squeaky bushings as that is their go to lube for their bushings.. i will try that and update yall

Op do you still have this problem? I have a big thumping noise from the rear as well after my track event. I had spl installed in the rear couple weeks back as well.

I had the same issue on my 350z. Exactly as the OP described it. My diff was moving up and down in the hole where it bolts to the subframe. Just very minor up and down movement that was making a lot of noise. I stuck a washer in there and tightend the bolt back up and it went away. I discovered it by letting a friend drive around a parking lot and I was sitting in the back of the Z with the hatch open, hanging over the rear looking at the suspension while we were moving lol.

yup i still have that sound.

hmm.. when i brought it to a lift.. me and my friend was trying to move everything to check if anything was loose including the diff.. but everything seems like its tight.. maybe ill check again in the spring time when i install my exhaust...

were u able to wiggle your diff by hand?

I don't think so. I think it would move when I jacked the car up by the diff, but I can't say for certain that it did. I'm thinking that the torque while driving was making it move though. You could always do what I did lol.

Another place to check Are the rear hangers for the muffler. When my mechanic installed my diff bushings he had to remove the muffler for clearance and didn't put all the bolts back on the hangers (only 1 per side) and the hangers worked itself loose due to movements in the exhaust system, this is where I discovered where my "clunk" had been coming from. I originally thought it was my rear sway bars endlinks had gone bad and bought new end links to replace it but it was the damn muffler hangers!:rolleyes:

hmm i will do that when my car comes back out the storage.. thanks for the advice! haha

i will b replacing my exhaust next season so i will check up on that too.. it will b nice if it was that tho lol but i doult it since it doesnt clunk on bumps.. just when im shifting or releasing the clutch fast..