I recently got my 3:73's installed by a ford master tech and they whined on the decel. So I took em back and they took another look and tried again and still the same whine on the decel...so I took them back again and they triplke checked everything and the gears are set perfectly...and they still whine. They did some research on the gears and they found that alot of people have had similar problems with the gears especially with a part number that ends in N. Wich mine do. I contacted American Muscle to see what they have to say and am just waiting on a response. Just wanna know if anyone else had this problem?? The full part number is : M 4209 F373N.

 

damn dat sux man

 

Hmm, let me know what happens. I am getting ready to have some installed myself. How's the acceleration, though?

 

I don't think he was looking for a response like that. Out of all the people i know with FRPP gears, none of them have complained that they whine. Now theres a couple people with Richmond gears and they whine.

How many miles on the tranny? How olds the car? Did you get the Master Bearing Kit?

 

accel is fine...just the decel whines....is the worst at about 70kmh - 30kmh

 

ya I got the master bearing kit the car has 88000km on it and everything else is really good condition...the cars an 03 GT. I was also told that the M in the part number stands for Motive...wich is wierd cause I ordered FRPP Gears!!

 

FRPP gears are made by Motive.

 

I'm not 100% sure but from what I've heard not ALL frpp gears are made by motive. Only recently have they started doing this. Part numbers with M in the sequence are the ones motive has made. His number starts with a M so I assume motive made these. Like I said I'm not 100% sure about this it's just what I've heard.

 

This is what I posted over at IMBOC.com, I'll just copy it over.

Everybody seems to think that Motive makes Ford's gears. This WAS true about a year ago. If you're buying gears, and the part number ends with an N, such as M-4209-F373N, then you're fine. I just got the answer from FRPP directly. He [Mike from FRPP] said Motive stopped making their gears about a year ago. He also said that the ONLY gear that was made by Motive that had the problem were the 3.55s. All other gears were fine, but Ford started making their own gears once again anyway. I hope this clears up a lot of confusion between Ford, Motive, and who makes what. So make sure you see that N at the end of the part before buying them if you REALLY want original Ford! Besides, the N also means it's made with a new process.

 

My 4.10 Motives whine and it is more noticeable since I switched back to the stock catback, otherwise it was more like a whistle. It is nothing that is going to break but could be irritating to some. My mechanic said he is 50/50 with Motives(for getting whine) and did not like Richmonds either. He said if I got a set of Auburn's and they whined the instal would be free, otherwise I would pay him the $225. I have had mine in for ABOUT 15K MILES AND NO TROUBLE EXCEPT FOR THE WHINE.
PS: There are likey thousands of sets of motives still out there with FRPP part numbers/boxed as FRPP so beware especially with a low price!
Summit is STILL selling FRPP gears nwith part numbers ending in A & M with the M being for Motive and the A for another supplier whose name I would have to search for.

 

The bottom line is they should not whine. Gear whine is caused by incorrect backlash.

 

The backlash is set perfectly...was done so and triple checked by a Ford Master Tech. It's been back there three times...they havn't charged me anything to rip it all apart again and take a look...they said it can't be any better of a setting!!

 

I have motive 3.90's that began to whine after a few hundred miles after the install. I took it to a local shop that is noted for their excellent gear installs. I had the master bearing kit installed too...didn't skimp on anything. I also changed the gear oil to redline after the break-in period, but that didn't help. My whine is when I cruise with my foot lightly on the gas. It starts to come on around 40mph. Its really not that bad, but it can get annoying(since the factory set up made NO noise). I guess that's the price we pay for performance.

 

By the way, my car is a 99 GT. I was almost tempted to use a thicker gear oil to maybe quiet things. I think there is one in the Summit catalog that says "for noisy gears" or something. But, a thicker oil will just lower the cars torque. Speaking of getting rid of noises in a vehicle, my old auto-tech teacher would always say: "thats what the radio is for".

 

I run Richmond Gears and I am happier than a blind Queer at a wiennie roast with mine. Gears of any kind should not whine.

The problem youre having sounds like the pinion depth is wrong or the preload on the bearings is off. Your guy keeps checking the backlash, which should be between .008 & .012 and saying everything is good but there is a lot more that needs to be checked.
When I set up a set of gears I like to make everything a little tighter because the will loosen up in a very short period of time.

In his defence, maybe there is something special with these new single pass gear cut. Have him check with Motive or Ford and find out if there is something different as far as setup with these gears. Good Luck.

 

I had a set of Motive 4.10's, bought from AM of course, installed about 1 month and a half to 2 months ago. I got about a mile away from the shop and turned right back around, because of the whine they made. Even though I had set myself to expect some noise from reading about other people's gear installations, it was alot louder than what I thought it should be, and certainly louder than what I expected.

My only two causes for concern though, where first and foremost, was it doing any damage to the gears and\or my car, and although 95% of the time, I'm the only one in my car and I almost always have the windows down and the stereo up, which does drown it out completely, there are times that my wife and\or son are in the car with me, which means no open windows (to windy for my son in the backseat in his car seat) and the volume turned down on the radio because of my wife. In these situations, it was impossible to ignore.

But the shop tech and owner said that the noise level is an issue of personal comfort. "Alot of gear installs come with whine, it's just that the variables of the brand of gear and the installation quality, make for the level of noise. As long as the whine ONLY occurs under decel and\or at coast, then again it comes back to personal comfort. If it occurs while under ACCELLERTION, then you definitely have a problem."

 

hopefully whenever i get my gears installed they dont whine as bad as yall are saying if they do then im just gonna have to live with it