SPL hard bushings for diff pumpkin = pronouned gear noise?
SPL hard bushings for diff pumpkin = pronouned gear noise?
I recently had a Quaife LSD installed along with 4.083 gearing and SPL hard bushings for the pumpkin and I'm hearing a lot of gear noise coming from the rear. The sound is a low pitched noise like the rear brake pads are dragging, to give you an idea of what it sounds like. At slow speeds (coming to a stop sign) there's almost a rhythm to it.
The shop that did the install is reputable, measured the backlash and installed the correct shims. However the noise still concerns me and I can't pinpoint the problem because I had 3 different things installed at once.
I had Quaife before (in my previous cars), and I know it doesn't make ANY noise...none...period! The gear shouldn't make any noise either..unless not shimmed correctly...which I'm hoping is not the issue here.
So the ONLY thing that could be making the noise is the SPL hard bushings (or so i'm hoping). That's why I'm here to ask fellow Z owners if anyone else had hard bushings installed and if noise was introduced.
thanks!
The shop that did the install is reputable, measured the backlash and installed the correct shims. However the noise still concerns me and I can't pinpoint the problem because I had 3 different things installed at once.
I had Quaife before (in my previous cars), and I know it doesn't make ANY noise...none...period! The gear shouldn't make any noise either..unless not shimmed correctly...which I'm hoping is not the issue here.
So the ONLY thing that could be making the noise is the SPL hard bushings (or so i'm hoping). That's why I'm here to ask fellow Z owners if anyone else had hard bushings installed and if noise was introduced.
thanks!
Last edited by 2fasst; Jan 7, 2010 at 08:44 AM.
I have the exact same setup as you and the same problem as well.
The SPL is not the issue since my car was dead silent the first couple hundred miles. Did you change out your bearings when you had it installed? My measurements at the install time were perfect, but after i told them about the noise they reopened and found that the pinion separated and damaged my new bearings. After my car is back and running I have to bring it back there for them to reinstall it.
The SPL is not the issue since my car was dead silent the first couple hundred miles. Did you change out your bearings when you had it installed? My measurements at the install time were perfect, but after i told them about the noise they reopened and found that the pinion separated and damaged my new bearings. After my car is back and running I have to bring it back there for them to reinstall it.
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I just spoke to the owner of the shop and he told me to bring it back and they'll open up the pumpkin and verify everything is correct.
I have over $2000 of parts in that pumpkin so I'm trying to catch this early before I create more damage. thanks guys..will keep everyone updated soon
I have over $2000 of parts in that pumpkin so I'm trying to catch this early before I create more damage. thanks guys..will keep everyone updated soon
The Quaife doesn't generate any noise. So would it be the gears, and if so...why???
Last edited by 2fasst; Jan 7, 2010 at 08:46 AM.
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Joined: Sep 2008
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From: pa
well i have a carbonetics diff with spl solid front and rear bushings with 4.08s and it whines. pretty much everyone who has put the 4.08s complain about the noise and the spl bushings dont help with the noise
I have a Kaaz lsd, 3.9 fd, and spl bushings. Same problem. Not too loud, but annoying. It is also speed/throttle dependent. I had my diff re-shimmed tighter to around .08 or so which is the tightest that 350evo recommends. The noise decreased a bit and the way it was delivered changed also. Like it makes the noise at different speeds than previously. No metal on the plug, and all new bearings/fasteners/seals/crush sleeve. It cost me $600!!!!!!!!!!!!!!!!!!!!!!!!!!! I was pissed!!!!!!!!!!!!!!!!!
So if I were you I'd change your diff oil often to see if theres any metal on the plug.
Unless the noise is excessive, then I would have it examined.
My diff requires regular oil changes so I can check it often. But as far as I'm concerned I wasted $600 that I didnt have!
So if I were you I'd change your diff oil often to see if theres any metal on the plug.
Unless the noise is excessive, then I would have it examined.
My diff requires regular oil changes so I can check it often. But as far as I'm concerned I wasted $600 that I didnt have!
Last edited by Wu-Watt; Jan 7, 2010 at 02:11 PM.
The fact of the matter is if your gears are noisy in of themselves then yes the noise will be more pronounced with the SPL bushings as opposed to the OEM fluid filled bushings by the sheer nature of the material they are composed of.
For those of you who have installed the gears at the same time as other differential upgrades it really is a crapshoot for anyone but someone physically working on your vehicle to try and diagnose what could be the cause of the noise. It could be the backlash, it could be the fluid your using or any number of reasons why you're hearing more noise from your rear-end.
For those of you who have installed the gears at the same time as other differential upgrades it really is a crapshoot for anyone but someone physically working on your vehicle to try and diagnose what could be the cause of the noise. It could be the backlash, it could be the fluid your using or any number of reasons why you're hearing more noise from your rear-end.
Last edited by Kwame; Jan 7, 2010 at 04:02 PM.
Such a noise, particularly when slowing down or going at lower speeds, is generally indicative of pinion bearings that do not have sufficient preload. Not always, but that's someplace to start. Pinion preload should be 24-28 inch pounds. Turning torque at the pinion should be 9-11 lbs inch. Remember, inch lbs, not ft lbs!
Backlash is another thing that can cause noise. It is generally described as a higher pitch type of noise (like a rining in your ear) and tends to be heard primarily under accel at any speed. Backlash should be in the 0.0039 - 0.0059 in range. Some like it a bit looser, as the rear will run cooler. Might be good for those full out race cars.
The side bearings caps are where there is a ton of preload. Factory specs call for 65-72 ft lbs. Ft lbs here, not inch lbs! This is pretty high considering the size of the components, but that's what Nissan calls for.
Not everyone who has gears installed get noises. There are alot of things that can cause noise, and there are lots of different noises which are indicative of different possible issues. It takes quite a bit of attention to detail to get things right, which is why some shops don't do this sort of work in the first place.
However, keep in mind, any solid bushing you have is going to take any noise already there, and magnify it. The factory soft rubber bushings are good and insulating some of these noises. There is always that give and take.
* edited per FSM
Backlash is another thing that can cause noise. It is generally described as a higher pitch type of noise (like a rining in your ear) and tends to be heard primarily under accel at any speed. Backlash should be in the 0.0039 - 0.0059 in range. Some like it a bit looser, as the rear will run cooler. Might be good for those full out race cars.
The side bearings caps are where there is a ton of preload. Factory specs call for 65-72 ft lbs. Ft lbs here, not inch lbs! This is pretty high considering the size of the components, but that's what Nissan calls for.
Not everyone who has gears installed get noises. There are alot of things that can cause noise, and there are lots of different noises which are indicative of different possible issues. It takes quite a bit of attention to detail to get things right, which is why some shops don't do this sort of work in the first place.
However, keep in mind, any solid bushing you have is going to take any noise already there, and magnify it. The factory soft rubber bushings are good and insulating some of these noises. There is always that give and take.
* edited per FSM
Last edited by Z1 Performance; Jan 8, 2010 at 07:19 AM.
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Joined: Aug 2002
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From: Australia
Such a noise, particularly when slowing down or going at lower speeds, is generally indicative of pinion bearings that do not have sufficient preload. Not always, but that's someplace to start. Front pinion preload is 9-11 inch lbs. Rear Pinion preload should be 24-28 inch pounds. Remember, inch lbs, not ft lbs!
Backlash is another thing that can cause noise. It is generally described as a higher pitch type of noise (like a rining in your ear) and tends to be heard primarily under accel at any speed. Backlash should be in the 0.0039 - 0.0059 in range. Some like it a bit looser, as the rear will run cooler. Might be good for those full out race cars.
The side bearings are where there is a ton of preload. Factory specs call for 65-72 ft lbs. Ft lbs here, not inch lbs! This is pretty high considering the size of the components, but that's what Nissan calls for.
Not everyone who has gears installed get noises. There are alot of things that can cause noise, and there are lots of different noises which are indicative of different possible issues. It takes quite a bit of attention to detail to get things right, which is why some shops don't do this sort of work in the first place.
However, keep in mind, any solid bushing you have is going to take any noise already there, and magnify it. The factory soft rubber bushings are good and insulating some of these noises. There is always that give and take.
Backlash is another thing that can cause noise. It is generally described as a higher pitch type of noise (like a rining in your ear) and tends to be heard primarily under accel at any speed. Backlash should be in the 0.0039 - 0.0059 in range. Some like it a bit looser, as the rear will run cooler. Might be good for those full out race cars.
The side bearings are where there is a ton of preload. Factory specs call for 65-72 ft lbs. Ft lbs here, not inch lbs! This is pretty high considering the size of the components, but that's what Nissan calls for.
Not everyone who has gears installed get noises. There are alot of things that can cause noise, and there are lots of different noises which are indicative of different possible issues. It takes quite a bit of attention to detail to get things right, which is why some shops don't do this sort of work in the first place.
However, keep in mind, any solid bushing you have is going to take any noise already there, and magnify it. The factory soft rubber bushings are good and insulating some of these noises. There is always that give and take.
The actual preload for the side bearings is 8 lb's measured pulling strength to turn ring gear assembly.
Also there is only one pinion preload setting & that is the 24 to 28 " lb's you mention. It is impossible to have different front & rear pinion bearing preload settings
The 9-11 " lbs is used to tension the pinion bearings when using the factory pinion hight setting tool. Once the pinion height is established the tool is removed.
Last edited by Nathan; Jan 7, 2010 at 05:27 PM.