New gears...whining

[badstang123]

Today I had Ford Racing 3.73 gears put in by a mechanic at my work. I work at Toyota but he was previously a mechanic for ford and has set up four or five 8.8" rears. We took it for a spin around the block and everything seemed fine. After that, on the way home I noticed a whining when I let off the gas. The whining is only at certain times. It doesn't happen in first or second gear and only right as it slows past 40 mph in 5th gear for a second. Most of the sound is in third and fourth from around 50 mph to 40 mph with my foot completely off the gas. If I slightly touch the gas it goes away. It also doesn't make any noise when I accelerate. Anybody have any ideas why it would do this when the car is slowing down? Second, could the gears make the tranny make anymore noise since it winds down quicker. Just wondering if it's normal at all or if something is wrong before I drive on it much.

 

[flashbang756]

You definately need to carry it back to him and let him hear it. Because most of all the times I've heard of someone with "whining" after a gear install, it was because something wasn't right.

 

[badstang123]

Also, if I push the clutch in while i'm decelerating the sound goes away. Does this mean it is the tranny?

 

[rio95]

listen by your shifter. It's not your gears.

 

[gatorbytes2]

You definately need to carry it back to him and let him hear it. Because most of all the times I've heard of someone with "whining" after a gear install, it was because something wasn't right.

I agree, Take it back and have him check the backlash, If not in proper range it will whine like that forever.

 

[gatorbytes2]

Also, if I push the clutch in while i'm decelerating the sound goes away. Does this mean it is the tranny?

harmonic sound coming from driveshaft due to steeper gears?? (just a guess) (maybe time for a balanced motorsport aluminium driveshaft)

 

[final5-0]

Drive it not one more foot

They are not set up right!

Perhaps if you don't drive it any more and you get things right

They may run quietly.

Usually once they start to make noise, the damage is done as far as how quiet they will operate for the rest of their life.

Just cause they howl don't mean they can't be used.

Years ago, me and my buds used to pick up 9" gear sets & punkins to use in our race cars for a song from high school guys who had tried to set up a third member but quickly found they were in over their head. They howled like a banshee but for a quarter miler, they were fine.

Maybe its a bearing gone bad ... Hope things go good for you

Grady

 

[69clark]

I won't do my own rearend gears, I leave it to someone that know what they are doing, but from what I hear it sounds like the backlash wasn't set correctly. Before some jumps all over me, I don't do gears but backlash must be right or it will not be good for the gear set, I just don't know if this is your problem or not, but it sounds like it could be.

 

[Yobi1Kanobi]

Its an incorrect install in my experience. That happen to me, I did my own ,then had some try to fix it , then fix it again, finally I had to get a new set becuz the pattern was already worn in. supposelly the shop that did it the forth time replaced them, I went ahead and got new bearings too. But havent heard from them again.....But then again That Shop rip me a new one and kept my car a month and said they did stuff on the car that i dont think they did so maybe they just adjust them. But since they were adjust three times before with the same results I think a new set of gears was the only thing that was going to make it go away.....And what an annoying sound that is too.

 

[sage2k]

hey guys I bought my car with 3.73s and the gears only whine around 38-43ish mph, any lower any higher no whine, is this the gears and if so is it bad? I drove it like this for 5-6k miles and it seems to drive ok?

 

[badstang123]

Here's an update on the rear. I talked to the installer today and he said the backlash was at .008 and that he had someone else double check it. He also assured me that everything else was set up right. I begged to differ because of the noise though. He said he would pull it apart again thursday and check everything. He even offered to buy me new gears if the wear pattern on these ones got messed up. It sucks that something is making noise but at least he is standing behind his work if something does need to be replaced.

 

[TheDamned]

that sux bro, if the mech is saying the thrut, that's damn weird.
good luck with it.

 

[WHITE94COBRA]

I know this may sound weird but on my old stang when I put the gears in it did the same thing, now heres the weird part when I took it back my mechanic told me to add ford motorsports friction modifier to it... And hour after putting it in and driving it home it was gone. And I never had any problems with the rear end or tranny as long as I had the car.

 

[flashbang756]

I know this may sound weird but on my old stang when I put the gears in it did the same thing, now heres the weird part when I took it back my mechanic told me to add ford motorsports friction modifier to it... And hour after putting it in and driving it home it was gone. And I never had any problems with the rear end or tranny as long as I had the car.

Friction modifier is a MUST. If this mechanic didn't put any in, then it's probably the problem.

 

[haulbalz]

Friction modifier is a MUST. If this mechanic didn't put any in, then it's probably the problem.

 

[badstang123]

Friction modifier was put in. I watched him do it.

 

[mo_dingo]

Here's an update on the rear. I talked to the installer today and he said the backlash was at .008 and that he had someone else double check it. He also assured me that everything else was set up right. I begged to differ because of the noise though. He said he would pull it apart again thursday and check everything. He even offered to buy me new gears if the wear pattern on these ones got messed up. It sucks that something is making noise but at least he is standing behind his work if something does need to be replaced.

Yeah but he had to shim the pinion gear to maintain correct pinion depth with the new pinion gear, and if he did this incorrectly the gears will whine.

And you bought FMS gears, so the backlash is almost always in spec. The 2 big carrier shims that ford installs from the factory were likely retained.

My guess is he left the same carrier & pinion shims b/c they are usually so close and didn't check pinion depth.
Scott