driveline clunk

[pufferfish]

JJ, you will not reduce noise with ANY aftermarket components. if you want to remove axle hop, the UCA will do that. it will also transmit MORE gear noise into the cabin. if you replace the panhard for a stronger one, it will transmit more road noise, which may include clunking. if you want to minimize the additional noise you will get, steer clear of heim jointed components.

ford worked hard to cover up a poorly engineered drivetrain. all of those soft bushings are to reduce the NVH, not cause it.

that said, I have owned all sorts of 79-95 mustangs before stepping up to this car. I have had 3.08's to 3.73's. traction locks and open diffs, worn out factory bushed to heim jointed control arms, torque arms, panhards, 1 piece aluminum driveshafts, little to no insulation, little to no interior, manual and auto transmissions. the rear is essentially unchanged from its introduction in 1986 (aside from length, mounting points and spline count) and I have never experienced the driveline noise I get now. I believe ford screwed something up royally in their quest to increase straight line and lateral traction.

The crazy thing is that there doesn't seem to be any consistency. some people get the whine. some don't. some get the clunk. some don't. some get the death rattle I experience. most don't. how does ford manage to make a largely homogeneous vehicle act so differently from car to car? it defies logic!

anywho, good luck in your quest for silence.

 

[jjgi5150]

Thanks very much everyone,

I'm not too sure exactly what I want to do with this situation. I have read about all the NHV issues with heim joints and poly bushings, and I don't necessarily want that in addition to the clunk. I really just want to get rid of the clunk. It is realtively slight, but definately there. I'm concerned that it will get a lot worse with time and routine wear.

I read about another CA '13 Boss owner who was experiencing some of these issues, as well as having issues of the rear end not staying firmly planted under acceleration. His simple fix was just to install a Whiteline UCA (a brand I would not use at this time), and per his feedback, it elimintaed most all of his problems.

I realize that each car is different...apparently some more than others...and I understand it may take a bit of individual tuning to 'fine tune' this rear end. I was just hoping to lessen the 'experimental' side of this problem. Sounds a bit like that may not happen.

And FWIW, I also have a bit of this....

Not to muddy the water but my '12 Boss has no driveline clunk under power or deceleration but it does make a clunk sometimes (sounds like its from the driveshaft or aft) when I am at a stop and am shifting from neutral to first.

So, I guess as much as I love the new Boss, I am expecting that I may have to deal with some clunks from the drivetrain for a while.

Thanks again,

JJ

 

[VTBoss302]

I'm not too sure exactly what I want to do with this situation.

Learn to anticipate when and where the issue occurs between accel and decel...

Ease the seat back, don't just let off the gas..

My 2HP.

VTBoss302

 

[unrealford]

Re: Re: driveline clunk

Learn to anticipate when and where the issue occurs between accel and decel...

Ease the seat back, don't just let off the gas..

My 2HP.

VTBoss302

I agree, I'm also going to say again, driveline slop is normal to a extent,
If you start worrying and messing around with it, you might find yourself in the same situation still or worse.
Drive it and put mileage on it.

 

[Senderofan]

Thanks very much everyone,

I'm not too sure exactly what I want to do with this situation. I have read about all the NHV issues with heim joints and poly bushings, and I don't necessarily want that in addition to the clunk. I really just want to get rid of the clunk. It is realtively slight, but definately there. I'm concerned that it will get a lot worse with time and routine wear.

I read about another CA '13 Boss owner who was experiencing some of these issues, as well as having issues of the rear end not staying firmly planted under acceleration. His simple fix was just to install a Whiteline UCA (a brand I would not use at this time), and per his feedback, it elimintaed most all of his problems.

I realize that each car is different...apparently some more than others...and I understand it may take a bit of individual tuning to 'fine tune' this rear end. I was just hoping to lessen the 'experimental' side of this problem. Sounds a bit like that may not happen.

And FWIW, I also have a bit of this....

So, I guess as much as I love the new Boss, I am expecting that I may have to deal with some clunks from the drivetrain for a while.

Thanks again,

JJ

From my experience....and reading results obtained by others....NVH will increase in our vehicles when changing to more rigid components. Not sure if you've had an opportunity to examine the rubber bushing for the factory UCA? It's amazing how soft it is....it must soak up a tremendous amount of vibration. Also, the factory panhrad rod is filled with granular material. Ford did their best to isolate the cabin from the NVH of the suspension.

I'm going to have to live with the clunks and gear whine. The trade off for me....is having the vehicles suspension set up to my liking. That being a more neutral balance, less brake dive and, if this sounds coherent, better feel in the seat of the pants of how the suspension and tires are working and the level of grip or lack there of.

Guess it's all a balancing act.....if you are more interested in having less NVH...then leave the factory components on. If looking for upgraded components....know that NVH will most likely increase with changes.

Good Luck.....I'm thoroughly amazed with how well these Boss's handle the curves.

Wayne

 

[shipdriver]

I'm kind of surprised by how many people suggest living with clunks, etc. My Boss replaced two successive Mazdas (RX-8 and before that a Gen 3 RX-7) and clutch clunk (esp. noticeable in 1st) is not what I'm used to (or any real driveline noise on 3,045 and 2,862 lb cars respectively). I'm on the other side of the planet on the nation's business, but as soon as I get back in few months, I'll be taking it in to get looked at. At first, it was "oh, must be a clunkier tranny than what I'm used to" then it just got annoying and "I'm not so sure this is how it is supposed to sound". Other than that the car is freaking awesome.

 

[Brandon302]

I'm kind of surprised by how many people suggest living with clunks, etc. My Boss replaced two successive Mazdas (RX-8 and before that a Gen 3 RX-7) and clutch clunk (esp. noticeable in 1st) is not what I'm used to (or any real driveline noise on 3,045 and 2,862 lb cars respectively). I'm on the other side of the planet on the nation's business, but as soon as I get back in few months, I'll be taking it in to get looked at. At first, it was "oh, must be a clunkier tranny than what I'm used to" then it just got annoying and "I'm not so sure this is how it is supposed to sound". Other than that the car is freaking awesome.

Each car has its quirks and that may be one of the Boss's. My moms RX-8 continued to get foam in the oil, after bring it in several times they talked with a Mazda tech who said it was normal for the rotary. But it does make sense to get it checked and have it down on the books in case anything does happen.

 

[jjgi5150]

Guess it's all a balancing act.....if you are more interested in having less NVH...then leave the factory components on. If looking for upgraded components....know that NVH will most likely increase with changes.

Good Luck.....I'm thoroughly amazed with how well these Boss's handle the curves.

Wayne

I probably need to clarify a bit. I am not overly concerned with a bit more NVH, I just really want to eliminate the clunk that is present. I probably should have strictly referred to "anti-clunk" as the main reference in this thread. I have not stomped on the Boss yet, but having read so many of the posts regarding excessive wheel hop and other bad manners with the rear end, I was thinking/hoping that a new, firmer UCA/mount and adjustable PH bar might be the easy ticket to stop those issues.

I agree with everyone, the overall handling is amazing for a live axle, heavy car. As I said, I am not ever planning on the car seeing the track, other than a drive up the coast to Monterey, some great mountain roads and other weekend trips. I guess I am just too used to American muscle cars that I have owned not having a 'clunker' rear end.

After I drive it a bit more, I am going to have the gears checked, just to make sure they are not the issue. If it works out that the lash is way out of spec, I may just elect to drop in a set of 3.91 (3.89?) gears, which I think would be an even more perfect ratio for me.

Take care,

JJ

 

[BossJake]

The only thing I noticed on my '13 is there does seem to be more slop in the gear mesh than other cars I have owned. If you get under the care and turn your driveshaft back and forth you can see how much slop you have. Slop is normal because the gears cannot be a perfect mesh or the heat produced would result in meltdown, however it does seem to have more than normal. I do not know what spec is for this... Does anyone know what it should be? i.e.. a half turn on the drive shaft, quarter turn... etc...


For me I do not notice any suspension slop at all. Others may have this but I do not so far.

 

[BossJake]

I probably need to clarify a bit. I am not overly concerned with a bit more NVH, I just really want to eliminate the clunk that is present. I probably should have strictly referred to "anti-clunk" as the main reference in this thread. I have not stomped on the Boss yet, but having read so many of the posts regarding excessive wheel hop and other bad manners with the rear end, I was thinking/hoping that a new, firmer UCA/mount and adjustable PH bar might be the easy ticket to stop those issues.

I agree with everyone, the overall handling is amazing for a live axle, heavy car. As I said, I am not ever planning on the car seeing the track, other than a drive up the coast to Monterey, some great mountain roads and other weekend trips. I guess I am just too used to American muscle cars that I have owned not having a 'clunker' rear end.

After I drive it a bit more, I am going to have the gears checked, just to make sure they are not the issue. If it works out that the lash is way out of spec, I may just elect to drop in a set of 3.91 (3.89?) gears, which I think would be an even more perfect ratio for me.

Take care,

JJ

If you haven't stomped on it yet and you didn't do any mods... Go for it! That's what warranty is for. If it breaks then you have good reason to bring it in under warranty. In my mind it's a great opportunity to find the weak points that maybe ford missed.

 

[NewBossowner]

The only thing I noticed on my '13 is there does seem to be more slop in the gear mesh than other cars I have owned. If you get under the care and turn your driveshaft back and forth you can see how much slop you have. Slop is normal because the gears cannot be a perfect mesh or the heat produced would result in meltdown, however it does seem to have more than normal. I do not know what spec is for this... Does anyone know what it should be? i.e.. a half turn on the drive shaft, quarter turn... etc...


For me I do not notice any suspension slop at all. Others may have this but I do not so far.

On average, 6 to 10 thousands, not sure the exact number but the majority of car differentials run in that range. I try to setup for as close to 6 as I can get, 10 is a bit loose for a manual car, although if it was being tracked, 10 would be prefered to give it more room for heat expansion.

 

[Senderofan]

I probably need to clarify a bit. I am not overly concerned with a bit more NVH, I just really want to eliminate the clunk that is present. I probably should have strictly referred to "anti-clunk" as the main reference in this thread. I have not stomped on the Boss yet, but having read so many of the posts regarding excessive wheel hop and other bad manners with the rear end, I was thinking/hoping that a new, firmer UCA/mount and adjustable PH bar might be the easy ticket to stop those issues.

I agree with everyone, the overall handling is amazing for a live axle, heavy car. As I said, I am not ever planning on the car seeing the track, other than a drive up the coast to Monterey, some great mountain roads and other weekend trips. I guess I am just too used to American muscle cars that I have owned not having a 'clunker' rear end.

After I drive it a bit more, I am going to have the gears checked, just to make sure they are not the issue. If it works out that the lash is way out of spec, I may just elect to drop in a set of 3.91 (3.89?) gears, which I think would be an even more perfect ratio for me.

Take care,

JJ

Well...My UCA is a Hotchkis...it has a Heim joint....I think this along with the rigid bushings in the new LCA's and adjustable panhard rod have increased noise coming from the rear suspension and whine from the gears. I just dropped my Boss off yesterday to have new relo. brackets welded in place....I bent the BMR's ( long story ). I asked the shop to check out the back lash in the rear gear...he felt about 9 thousandths is where I should be...we'll see. In any event....I would gladly do my suspension mods over again if I had the chance to re-set. The car is now set up more to my liking...whether on the track or off. Next steps will be stickier tires and performance brake pads.

I think it's very important for folks to know that there are trade offs with some of these upgrades. Perhaps it was just me being naïve.....but I had no idea there would be a significant increase in sounds from the rear end. I've become accustomed to additional sounds....but I feel folks need to be aware of this.

Good luck with what ever mods you decide to do. As I said earlier...I'm extremely pleased at how well these cars can handle....and all for a price much lower than many European competitors.

Wayne

 

[unrealford]

Re: Re: driveline clunk

I probably need to clarify a bit. I am not overly concerned with a bit more NVH, I just really want to eliminate the clunk that is present. I probably should have strictly referred to "anti-clunk" as the main reference in this thread. I have not stomped on the Boss yet, but having read so many of the posts regarding excessive wheel hop and other bad manners with the rear end, I was thinking/hoping that a new, firmer UCA/mount and adjustable PH bar might be the easy ticket to stop those issues.

I agree with everyone, the overall handling is amazing for a live axle, heavy car. As I said, I am not ever planning on the car seeing the track, other than a drive up the coast to Monterey, some great mountain roads and other weekend trips. I guess I am just too used to American muscle cars that I have owned not having a 'clunker' rear end.

After I drive it a bit more, I am going to have the gears checked, just to make sure they are not the issue. If it works out that the lash is way out of spec, I may just elect to drop in a set of 3.91 (3.89?) gears, which I think would be an even more perfect ratio for me.

Take care,

JJ

You won't find 3.90 gears that are quiet, Ford Racing don't sell them Richmond sells them but the teeth are straight cut and will make noise.

 

[unrealford]

OK, seems you guys jinxed me. I have some serious clunking, whineing and rattle in driveline. Going to drop it off at dealer and see what they say. I have a pretty good dealership. Want to have it looked at before I gave the RXT Clutch installed.
All honestly, I haven't really even driven it much the last 3 weeks, it's not enjoyable at all.

 

[Justin]

Re: Re: driveline clunk

You won't find 3.90 gears that are quiet, Ford Racing don't sell them Richmond sells them but the teeth are straight cut and will make noise.

motive makes a set. I have seen some work out well and others whine and or break teeth
http://www.summitracing.com/parts/mgr-f888390/overview/