Installed 4.10's and car is making weird noises
 

Hey everyone I just had some 4.10's installed and right when I pull away from the shop I notice 2 new noises. The first one
sounds like it is coming from my CAI it is a high pitched whirring noise, but it only makes this noise when I give my car some gas.


The other sounds like its coming from the rear axle where the gears are and its a lower pitched whirring noise. The noise in the back only happens when I am going about 50+ and my rpms are from 1-1.5k. Anyone know what this could be? My gears are Ford Racing. I am aware that some people get a chirping noise from their motive gears but I was also under the impression that Ford gears would not do this. Any ideas as to what this could possibly be would be awesome.

most gears are the same (the FRPP gears are actually made by Motive), the sound comes from poor install. if they're installed correctly-no gear will chirp, but if they're not in just right (it's a very difficult process that has to be done perfectly) all gears will chirp. for now maybe give it some time to work it in....

Yeah thats what I was thinking I have 200 miles on them since install. The sound doesn't bother me too much because the range that it makes the sound is very small but I still would like it if it weren't there

My gears are doing the same thing. I think i will just live the little noise that it makes.

You should not hear any noise from a properly installed set of gears.
They don't need broken in to eliminate sounds either.
Break in is important in my opinion though.

It is good to keep the car under 60mph for the first 100 miles. The loads generated while driving, force any tiny, tiny high spots on the gears back into the metal. This is called "work hardening". Work hardening is similar to forging in that it compresses the metal into a very compact and hard formation. This can only happen if the metal surfaces are lubed and kept cool. If the gears get too hot, it will soften the surface instead of hardening it.

The gear whine is typically caused by an improper backlash. Gear install is alot of trial and error shimming to get the gear mesh and the backlash set perfect. Sometimes lots of time. Maybe the shop rushed through it and figured " good enough. "
I'd be heading back to make them do it right.

Bwhipple is right, the low pitched whirring noise or "howling" comes from an improper backlash. I recently installed a set of 3.90's in my car, the shop quoted me 3 hours, but it ended up taking the guy 5 hours because he wanted to make certain he set everything correctly. You need to bring it back to your installer to correct the problem, if you don't it is going to create premature failure on your bearings and ring and pinion.

Scott

Alright I think I will take it back to get it fixed.

I gaurantee that shop is gonna say.. " no. the noise is normal that is what happens when you put in aftermarket parts" heh..

i've heard a lot of these stories. who does good installs? should i look into some local mechanic shop...or qould i bigger chain be better. tires plus, peb boys, etc...

doin some planning for my 4.10 install project!!