96lt4c4

iTrader: (5)

I have a cousin that lives in Fancy Farm KY...Anyway, good luck! Look up some of my old threads. I have been through the same thing you are going through. I have tried pretty much all the popular brands of gears in my 9" and they all made noise. Most 9" gears are made for racing so they make more noise. The pinion rides lower on the ring gear on the Ford 9 for more tooth contact which makes things worse. The only gear I did not use was the Motive "STREET" gear or blue box gears. I had a new one in the box but sent it back to install a new Strange/US Gear, guess what really bad gear noise. My car does not go to the strip so I put the 10 bolt back in, all new parts, rebuilt with a Motive performance 3.89 gear. It makes some noise but nothing like the 9 inch. Your pattern looks pretty good, maybe a little deep on the coast and to far out on the drive. Sometimes you have to comprimise. More than likely there is nothing wrong with it. It is just going to make noise. I have beat the snot out of my 10 bolt in the car now and its doing just fine.

This car has a 9 inch in it, I have seen it in person, listen to the rear in this car at the end of the video.



I have heard that the Motive Blue Box gears are quiet in the 10 bolt, and read an article where a guy used them in an old Mustang and they were quiet.

http://www.7173mustangs.com/thread-h...-a-ford-9-inch

The suspension setup in these Camaros do not help either mainly the torque arm.

FancyFarmSS

iTrader: (5)

Thanks for the info man. Center section is currently in the hands of Strange, getting new Motive 3.50 ratio ring and pinion. Just hoping that a new gearset along with a new person setting it up might help. Might, might not, but feel like I need to try something.

Who's your cousin btw, if you don't mind me asking? Fancy Farm is pretty small, so I might know him.

96lt4c4

iTrader: (5)

I really hope that you end up with a quiet rear, I gave up on mine. Still have the 9" and may try again someday, but right now the 10 bolt is doing all I need it to do. The quietest gear I had in mine was a Yukon 3.75 ratio. The gears were cut different, than say the Motives, or the US Gear. More like the stock gear in the 10 bolt. The teeth were smaller. That gear went out due to my axles bottoming out in my posi, but thats a whole nother story. My cousin's name is Chuk Skaggs, he is married to Michelle Toon, her familly has a pretty good size farm out there.

GO CATS!

texas99Z28

I wish I had one of their re assemblies on my car!!!!

CamaroZ28_LS1

iTrader: (5)

I think I would be very concerned if my 9" didn't make any noise lol. It's a ford truck industrial rear end, what do you want from it? Aint no mercedes benz.

As far as 10bolts go, I went through three of them before my 9" LOL!

96lt4c4

iTrader: (5)

Watch this video and listen to the 9" in this high end Autocross car. It has a Currie 9" in it.

FancyFarmSS

iTrader: (5)

Haha, yes, Go Cats, in basketball at least.

I can't say I know your cousin Chuk, but I think I know Michelle. What a small world, didn't figure anyone on this site would have heard of Fancy Farm

Thanks for the video. I watched it, and definitely heard a whine that sounds a lot like mine. I guess I get your point that even rear ends that are set up by "the best" appear to have this whine, so maybe it's normal. But it is still very annoying, and just doesn't seem right to me. I guess I don't even know which Ford vehicles originally came with a 9" from the factory, but weren't they quiet?

LS1-IROC

iTrader: (4)

Factory Ford 9's were usually pretty quiet. Your best bet if you want a quiet 9" is to use a FoMoCo gear set.

FancyFarmSS

iTrader: (5)

Well, just to let everyone know, the 3rd time wasn't a charm for me As CamaroZ28_LS1 said and 96lt4c4 suggested with the video, I am beginning to believe noise is just inherent with these rear ends, especially with the torque arm setup, etc. I have. This is what several people have been trying to tell me from the beginning, but I just didn't believe it should be this way.

With this last gear swap, the only thing that changed is the whine started at a lower speed, and didn't go away much after I let off the gas. Maybe the rear end is performing the way it should, but it is not meeting my expectations as a daily driver, so I'm swapping the stock unit back in. In the end I blame most of this on myself for not asking the questions I should have, and for buying such an overkill unit. Maybe by the time the stock rear decides to go , I'll be a little more willing to compromise driveability and strength, and I'll be able to get some use out of this "bulletproof" 9".

gofastwclass

iTrader: (2)

So that's as good as it gets... hmmm. Disappointing.

Mine is louder than that but it's never been "quiet," even during break in. I may play with shims and see where it goes.

Mine is dead silent on the coast side but very loud from 45 to around 75. Above 80, it's quiet again.

96lt4c4

iTrader: (5)

I think thats the problem around here is everyone is made to believe they need a 9 inch. Most of the street cars on here do not. I have a 9 inch sitting in my garage floor myself. Mine is home built though. A lot of the 10 bolts that go boom on here, there is no telling what they have been through. I can build you a pretty stout 10 bolt if you want to bring it to me. I am working on my 5th high horsepower 10 bolt build for someone right now. So far I have not had any fail that I have built. Some make noise some do not. But even the loudest 10 bolt I have put together does not compare to the noise a 9 inch makes.

I will never put 4.10's in one, the pinion is to samll, 3.90 is as low as I will go. The motive orange box gears are a good strong gear, might get some noise but it is liveable.

FancyFarmSS

iTrader: (5)

Yeah, I had myself convinced that that's what i needed. And I'm sure I would have been very happy with it, had it not been so noisy, or had I wanted to use it solely on the track.

Swapped the stock rear back in over the weekend, and even though it sounds strange, I couldn't be happier.

cire0105

Old thread but still relevant as I just bought an MWC custom 9 inch with the strange aluminum housing and 3.89 motive gears. I have essentially the same noise described by the OP, cruising throttle 40-60 mph I have a very audible gear whine, freeway speeds it almost disappears. At no other times does it make noise (accel, decel, other speeds). I had my 9 inch shipped assembled by MWC, so I trust the pattern was set correctly, but I will inspect it anyhow. If it looks good I may try playing with .002-.004 of pinion shim depth to see if I can make the noise more livable. My car is a street/everything car and my goal was to make the rear end bulletproof, which I'm sure it is now, but the cruising speed gear whine puts a ***** in an otherwise impenetrable armor. Otherwise I am pleased with the product, fit, finish, ABS still works. I am just about at the 500 mile break-in now. I will report back with my findings.

I wonder if different brand gears would be less audible? Maybe US gear with some of their treatment options?

Mart00SS

iTrader: (19)

Well this thread was depressing, as the resolution was that he swapped the stock 10bolt back into the car to get rid of the noise. LOL. It sounded like when he messed with the pinion depth it brought the noise on earlier. However this was 1 case from 8 years ago. My question is what do you guys have for exhaust??? Is the whine loud enough to hear over the exhaust?
My 10 bolt is loud as hell with the cutout closed pushing the exhaust through the stock muffler, open the 4" cutout in the I pipe and no more rear whine.

gofastwclass

iTrader: (2)

cire0105, what chassis is this in?
Years ago I had a 9" in a 2002 WS6 with an aftermarket torque arm and it was noisy to my ears (I have really good hearing) but it didn't bother most who rode with me though they could hear it. Several iterations of gear adjustments, sound damping material, replacement bushings, etc. later the noise only changed but didn't go away. When speaking to an old time guy who built rear axles for years about the issue he told me at one time the gears he found that were the quietest were the Ford gears directly from the parts department. Of course the OEM vehicles are no longer produced as such the OEM gears he was referring to are long gone as are the vehicles they were intended to repair.

The old timer's theory was the original gears were made with either a different heat treat process, a different alloy of steel or even a different cut that made them softer, quieter and more street friendly than the current crop of performance oriented products. Since everyone wants (or thinks they want) 100% performance with a 9" the aftermarket has delivered which leaves those of us who don't want to shear things off regularly to deal with racecar noise or use a different housing. No idea if this is true and it was his theory based on his experience.

My personal theory is the old timer had a point and I'll take it one further. If you're in a car like an F-Body with a torque arm it is like a giant tuning fork - especially when coupled with an aftermarket torque arm. When I moved the same housing, differential, axles and gear to a car with a four link the annoying gear noise was greatly subdued. I can only assume (as I have not tested) that the harmonics of the noise, chassis and seat placement conspired to create an annoying sound - even with full interior. The other car didn't have a torque arm, has no carpet or sound damping material and two seats, yet the gear appears quieter than when in the WS6 I built it for.

I know it doesn't change anything and is just two more theories on what's going on.

cire0105

@gofastwclass

Thank you for your input, your theory is worth looking into. I have a 2001 trans am with the MWC long torque arm with the T56 crossmember. The gear whine is almost livable, but I want to do my due diligence to try and minimize or eliminate it. I believe the mount to the crossmember is a hyme joint, would have to modify it to a rubber bushing. Also I have the watts link option which also likely adds to the noise transfer. The price we pay for performance. Not sure how the OEMs make (relatively) quiet sharp handling 700 hp cars and we can't.

HioSSilver

iTrader: (8)

Ive seen gears you just can't get the whine out of.....especially richmonds. I just set up some 4.88 motives in a 8.8. Nothing i could do to get the drive side to pattern right and i tried and tried.

Now the next thing is if you want to reduce driveline noise everything must be in rubber. EVERYTHING! If you mount everything in rubber and leave one rod end or solid mount you will not hear a change. It will ALL come through that one mount.

With that said ridetech makes some nice adjustable bushings that screw right into the mwc stuff. You will have to mod some stuff but they will make your street car ride/isolate like a street car.

cire0105

@HioSSilver

Thank you! Switching from hyme to rubber bushings maybe the performance-to-noise compromise I am looking for in my street/everything car. I will look into ridetech's bushings if the gear pattern checks out, I assume you mean their R-joints?

Quick google search I also turned up these, though I would have to check size/thread
https://www.speedwaymotors.com/Speed...RoCYTEQAvD_BwE

98cherrySS

iTrader: (2)

I would not trust that the pattern is correct... You'll probably want to at least try to shim it but I would suggest a full inspection of the case/gear assy. I had the same issue (among many others) with the unit I purchased from them. While shimming helped, it did not completely resolve the noise issue.

While you are at it, make sure that every fastener on the differential is tight. I had the fasteners on the differential from them back out (no loctite) and and grind against the case which littered the inside of the housing with millions of shavings. Ultimately compromising the gears and bearings. I ended up replacing the differential and gears on mine. I went with US Gear's Steath series with the Lighting treatment. Absolute silence since. Good luck.
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HioSSilver

iTrader: (8)

There ya go. My ridetech is similar but actually have a rubber bushing which isolates even more. Mine is not the r joint. They've been on the car forever now. Last time i looked on their site i couldn't find them.....but they have alot of stuff on there so i may have overlooked them.

Rod ends simply suck for the street. The only success I've had using a rod end on the street is having the rod end on the rear end side and a bushing on the body side. That seems to isolate pretty well and still the the rear end articulate freely.

Alot of guys remove the rear spring isolators to. I had them out for a good while and put them back in. The car is much smoother with them in.