[Harryburroughs]

Hey Guys,

Ive been chasing down terrible whine / gear noise for months. I will post a link to the noise and hoping to see if anyone else has had something similar and if they resolved it. The noise is there all the time but cannot really hear it until 50mph then when she's in overdrive its overbearing... If I dip the clutch the noise goes away.

I have a quick performance 9 inch rear end with less than a 1000 miles on it... Its got 3.70 Motive gears along with a SOT 3 Link kit. My current shop said it may be the diff or 3 link so I had the centre section removed and the back lash set up again, axle straighten and I still have those dam noise. Quick performance are blaming the suspension company, the suspension company have said they have not had this issue previously so im just in the middle with a great driving restomod which I cannot stand to drive on the freeway....

Work ive done...
Suspension is new.
Diff is new
Back lash has been set up again
Axle has been checked and straighten
Axle bearings have been replaced
Tyres are brand new
Driveshaft has been balanced
New UJ's

Cheers.

 

[Harryburroughs]

Quick performance / SOT 3 link whining noise

youtube.com

 

[Harryburroughs]

@Harryburroughs I have the same setup you have with the same vendors. Everything from SoT has been right and everything from Quick Performance has been wrong! You will get a bit more noise transfer with the short upper link but it is very minor in my car. How can QP can blame SoT for a gear whine. My QP axles slap around in the center section at low speeds because they are too short and machined undersize.

Hey buddy, I agree I love the SOT stuff. Quick performance have said the upper link and joints are to blame for this noise…. Basically told me without changing my suspension. I can’t get rid of the noise and having a 3 link from SOT will cause noise to come directly in the cabin. The noise is even worse in person it’s unbearable for long journeys.

 

[Harryburroughs]

Well Harry, the first thing I noticed is you are driving on the wrong side of the road. Just kidding. If I had to go out on a limb, I would say that the noise is coming from the mating of the gears. Just my opinion. I don't know why some gears seem to make noise. I had a 1983 Mustang, 7.5" rear. Backing out of the garage slowly, the car came to an abrupt stop. Pulled it back in, took it apart and a spider gear tooth had broken off and had somehow gotten between the ring and pinion and that's why the abrupt stop. Not much really noticeable on the ring an pinion.
I bought a new Ford posi unit and installed it. No problem, set the backlash. I never got the whine out of that rear end. I even paid a "expert" and same result.
I thought I remember someone recently having problems with a rear end with Motive gears?
Personally, I like Richmond gears. They come from the factory with the pinion depth and backlash scribed on the gears, of the setup dimensions used at the factory to run the gears in. I set them up to those dimensions and have never had a problem.
I am not saying to run out and change your gears, but if you are pulling your hair out trying to figure it out and you are throwing out money chasing this, it may be worth your while to install a different brand of gear.

Just thinking of this, you may want to check the drag on the pinion bearings to see if the gears were set up too tight as far as the pinion bearings. Just a thought.

I was thinking for changing the gears but trying to get a define answer as I probably wasted 1000 bucks changing the bearings, doing the re lash, Straightening the axle

 

[Harryburroughs]

I guess some people in here would have loved to see a pic of tooth pattern. I've had a new rear that whined, despite it was built by a guy that build Ford axles for a living. The pattern looked wrong to me, and a homemade readjusting to something that looked better, removed 95% of the noise. I've gotten the understanding that a lot of the aftermarket gear sets are really sensitive regarding the setup, if you want them to be silent. Something about that they are machined with a different process than the OEM gears.

 

[Harryburroughs]

You already know where the issue actually is............. I don't know what more to say.

I believe it’s the Rear end but the local axle shop blamed the top link too so I’m not making any progress

 

[Harryburroughs]

I bought a set of the low end motive gears for my truck and they whined from day one and tried to adjust for it and it never went away. I only paid $25 for them so other than my time it was a lesson learned not to buy cheaper gear sets. I eventually installed ford gears in my truck and no more noise.

The motive gears aren't cheap. I think my next move is to get a set of OEM gears but its so confusing when people are blaming everything else but the axle.

 

[Harryburroughs]

OP its very clearly gear whine - common issue with aftermarket ring and pinion sets. I would look at a US gear ring and pinion set in one of the the known 'quite' ratios.

The mesh photos look ok, but it dosent matter sometimes regarding noise. When the backlash was reset was it changed? Was the runout of the ring gear verified ok?

I sent the centre section to a local shop and they said everything was ok...

 

[Harryburroughs]

Do you know anyone that has a 9" third member that you could install to prove that what you have is causing the issue? It's just a thought.

If I can find some local enough I was going to try that.

 

[Harryburroughs]

I have a QP housing and center section. 3.89 truetrac. Not sure what brand of gears but it was their default. I am running the 3 link. No whine. I see you gave up on the 8.8"?

I thought it would make life easy just going to a correct length 9 inch but it has not been the case LOL

 

[Harryburroughs]

Well it's obviously not based on the noise in your video.

I would try a different ring and pinion set, new bearings, all from a different supplier and built by a different builder.

Yes I agree. something isn't right. Its good to see people with the 3 link without the problem so I can show the shop this. so I dont just get 'this is what happens when you add solid joints and a 3 links direct to the body' or 'its normal for a 3 link to to this'

 

[Harryburroughs]

Not to mention they’re only solid on one side. I agree with @Nailbender. Or you could raise hell with QP and make them send you 3.89’s.

Ive spoken back and fourth with them for months. they've just blamed the solid joints. I guess the only way to find out is replacing the gears with some which hopefully dont whine as much.

 

[Harryburroughs]

Dealing with QP can be like pissing in the wind. If you whine enough they will do anything you ask. I PM with forum member who has had similar issues as I have had and has the patience to deal with QP. I have a relatively short fuse and Strange Engineering is 60 miles North West of me and Moser 120 miles South. Quality of life.
I have the exact same rear suspension as you with 3.25 gears from "QP" and zero whine. As I have stated repeatedly, you're gonna get a little bit more noise with less rubber insulation, but it has not been offensive in my case.

Thats great to know. I will be showing QP the comment. It was too easy just to blame the suspension.

Im ok with a little extra noise for a great handling car but the noise ive got is unbearable to a point I dont take my car on the freeway. My next step is to change the gears to a set of OEM ones and go from there.

 

[Harryburroughs]

QP have agreed to send me a new set of Motive 3.70 gears from a production batch they have tested which are 'quiet' and a set of new bearings. I hope this will solve the issue.