sounds from beneath the hood.

[O3 pharoh]

When i am driving at about 45-60, i can hear a howling/ roaring sound. The sound is louder when i get let off the gas. Not only is it annoying but also getting scared that something else is wrong. I just got my car back after the trans was redone and the rear gears(4.10) and trac-lok rebuild. Before the trans swap i was running without overdrive, could this have scarred something in the motor. Never really noticed the noise before hand. any ideas? thanks.
-T

[Zack]

Sounds like the shop who installed the gears did not set them up properly.

[Blackened300a]

Sounds like the shop who installed the gears did not set them up properly.

+1 Gear whine.

[O3 pharoh]

why would the gear whine be heard under neath the hood? wouldn't it be heard from the ass end? is this just normal of the 4.10's or is it going to have problems in the future??

[Blackened300a]

why would the gear whine be heard under neath the hood? wouldn't it be heard from the ass end? is this just normal of the 4.10's or is it going to have problems in the future??

It only sounds like its coming from under the hood. Do you hear it at idle or while not moving?

The FMS 4.10s have a whine to them but only at light throttle.

[rayjay]

Add Ford friction modifier (4oz) to the differential and see if the sound goes away.

[RF Overlord]

Before the trans swap i was running without overdrive, could this have scarred something in the motor. No. There's either something very wrong with the transmission rebuild or, as the others said ^^^, your gears are not set up correctly.


Add Ford friction modifier (4oz) to the differential and see if the sound goes away.Friction modifier is only to prevent the clutch pack from chattering on turns.

[Joe Walsh]

It does sound like the gears were not set up properly.
Determine if it is related to the speed of the vehicle or the speed of the engine.
Rev the engine while in neutral and not moving and see if the noise is present or changes.
Rev the engine while in neutral and rolling along at 50 mph and see if the noise changes.
Put the vehicle in neutral while rolling at 50 mph and see if the noise goes away and/or changes as you coast down.
Take it back to the shop that did the repairs and have them diagnose it.

[fastblackmerc]

+2 gear whine......

[O3 pharoh]

It does sound like the gears were not set up properly.
Determine if it is related to the speed of the vehicle or the speed of the engine.
Rev the engine while in neutral and not moving and see if the noise is present or changes.
Rev the engine while in neutral and rolling along at 50 mph and see if the noise changes.
Put the vehicle in neutral while rolling at 50 mph and see if the noise goes away and/or changes as you coast down.
Take it back to the shop that did the repairs and have them diagnose it.


I completed some of the tests listed above and i am starting to notice that of course you guys are right. I was driving with windows shut and it seems the noise is more present from the rear. It is a very light whine from the rear at lower speeds, but when i get around 50-60 and accelerate the whine gets pretty noticeable and even more so on deceleration. When the installation was going on, the mechanic said the install was probably one of the most precise he has done as far as measurements go. I guess big question is: is this the normal sound and i am just not used to hearing it, or is it truly a problem with install. Thank you all for the great advice, can't say enough about the knowledge on this site!! big props
-T

[fastblackmerc]

I completed some of the tests listed above and i am starting to notice that of course you guys are right. I was driving with windows shut and it seems the noise is more present from the rear. It is a very light whine from the rear at lower speeds, but when i get around 50-60 and accelerate the whine gets pretty noticeable and even more so on deceleration. When the installation was going on, the mechanic said the install was probably one of the most precise he has done as far as measurements go. I guess big question is: is this the normal sound and i am just not used to hearing it, or is it truly a problem with install. Thank you all for the great advice, can't say enough about the knowledge on this site!! big props
-T

It's not a normal sound. The gears were setup wrong!

I've had my 4.10's in for over 50k miles and have had NO noise out of them.

[Glockafella]

I have a slight noise from my newly installed 3.55s but only when I have Cruise control on...wierd huh?

[J-MAN]

Lidio did mine-no noise.

[RF Overlord]

It's not a normal sound. The gears were setup wrong!^^^what fbm said^^^

...or the gears are defective.

[rayjay]

Just had mine done 2 weeks ago, no noise. My guy said the same thing, his math was perfect and he hit it dead nuts 1st time. However, he does teach this stuff...

[babbage]

Suppose to take it easy for 300-500 miles break in time. Use Dino oil for break in peroid - THEN use synthetic.

Good gear installers will use marking compound to check the wear pattern on the gears or use a special Ford pinon depth tool. Your gears need to probably come out. You'll need a new crush sleeve too probably.

I'd go back to the installer. Did he tell you to take it easy for the brake in?

[ctrlraven]

Do a new set of gears really need to have dino oil ran first then synthetic? I was just going to have Royal Purple put when my 4.10s get installed. I mean I guess it wouldn't be too hard since I will have a TA Performance cover installed also with a filler/drain plug already in it.

[O3 pharoh]

Suppose to take it easy for 300-500 miles break in time. Use Dino oil for break in peroid - THEN use synthetic.

Good gear installers will use marking compound to check the wear pattern on the gears or use a special Ford pinon depth tool. Your gears need to probably come out. You'll need a new crush sleeve too probably.

I'd go back to the installer. Did he tell you to take it easy for the brake in?

Yes, I knew of the break in period, i made sure that i took an easy on the car for closer to six hundred miles. I wanted to break everything in very evenly, although he said the trans didn't need i, it has always been my way of doing things. The fluid used was mobil 1, he added extra friction modifier because of the carbon trac-lok setup that i put in. I had to drive the car on the hwy coming home. Had a few 10min drives and stops before i left, and stopped three times on the way home so that the trans and gears could cool down plenty. Plus the weather was decent at 55-60 degrees. I will have my good friend and mechanic take a look at it. This sucks, finally breath some life into this beast, love it, now time to redo it.:mad2:
Thanks guys, will let you know how it plays out.

[RF Overlord]

Use Dino oil for break in peroid - THEN use synthetic.I've never heard that one before.


Do a new set of gears really need to have dino oil ran first then synthetic? I was just going to have Royal Purple put when my 4.10s get installed.I had the tech put in Motorcraft synthetic 75W-140 when he did my 4.10s. No problems 30,000 miles later.

[babbage]

I've never heard that one before.

I had the tech put in Motorcraft synthetic 75W-140 when he did my 4.10s. No problems 30,000 miles later.

Yep. It's sound advice. you want the gears to wear a bit and rub off and essentially "set". Then you drain out the breakin oil and any metal particulate replace with good synthetic. You'd never want to use synthetic oil on your piston rings - they'll never setup properly.

Yes it's a bit anal and going far but hey -- why not do it better if you can.

For breakin I went with Costal cheap ass gear oil with generic FM, then after 500 I used AMSOIL 75w-110 which has FM already in it. also installed a set of FRPP 3.73N with a Dennis Reinhart rebuilt 28 spline carbon fiber clutches trak-lok unit (highly recommend) plus the good ol Alcoa Y2k special driveshaft topped off with Trick Flow gridle and 5lbs on the caps. Totally quiet very solid setup, I'm happy with it.

[fastblackmerc]

^^^ he doesn't know what he's talking about ^^^

DO NOT use dino oil for break in....

DO NOT use dino oil for break in....

Use a good quality synthetic oil like Redline 75w140 from the get go and you will have no problems as long as the gears are setup correctly. Don't even have to add friction modifier. With new gears you do have to take it easy for the first 200 - 300 miles... no burnouts, no high speed cornering and no constant speeds for long times.

[DOOM]

Mine makes a noise from under the hood too! :help:
Everytime I go wot all I hear is WWWWWHHHHHHHHHHHRRRRRRRRRRRRRR EEEEEEEEEEEEEE!!!!!!!!!!!!
And then my rear end breaks traction (and no I don't have gears installed) :dunno:

[ChiTownMaraud3r]

Could it be something in his trans rebuild causing the whine as well? :dunno:

[dhawke98]

For what it is worth, I had my 4.10 gears put in by the guy who does it for all the police departments around POrtland, Or and for the Ford shops. My gears made noise for about the first 250 miles. He used the friction modifier and everything else. Sound went away and all is good. Have put on about 6000 miles on the gears (about 5 at the track) and no issues.

[O3 pharoh]

Could it be something in his trans rebuild causing the whine as well? :dunno:


We are hoping not anything in the trans. The guy is good with sevice, i told him the problem, i just have to get another set of ears to confirm the gears are whining, then he will replace cause the shim's would be off. He said he used the largest shim that he could within the specs. I guess the old lady i was told owned the car before me must have been a hot-rod granny. :burnout:Mechanic said the rear end was just eaten up bad. He said if gears are whining that it could be caused by damage and whole rear-end would have to be replaced or he would have to put a bigger shim than spec allows.

[babbage]

^^^ he doesn't know what he's talking about ^^^

DO NOT use dino oil for break in....

DO NOT use dino oil for break in....

Use a good quality synthetic oil like Redline 75w140 from the get go and you will have no problems as long as the gears are setup correctly. Don't even have to add friction modifier. With new gears you do have to take it easy for the first 200 - 300 miles... no burnouts, no high speed cornering and no constant speeds for long times.


AMSOIL says not to use their product until after your gears are broken in, I trust and accept their advice.

For gear break in period you want them to heat up and get hot, which they won't be as hot if you use synthetic for the initial fill and with regard for constant speed. Don't drive more than one hour at a time etc.

Most differential wear occurs during the break-in period. Beacause differentials are not equipped with filters, break-in metals are suspended in the oil, causing increased wear as the particles mesh between the gears. Hauling heavy loads and towing heavy trailers cause additional stress to the differential during the break-in period and can cause premature differential damage or failure. Changing the gear lube after the break-in period (about 3,000 miles) is a low-cost maintenance investment that provides a significant payoff, including greatly reduced wear, extended differential gear and bearing life and protection for expensive vehicle investments. Auto manufacturers recognize the importance of draining abrasive break-in materials. Some manufacturers recommend an initial drain interval of between 500 and 3,000 miles.

New differentials go through a break-in period and should have the break-in gear lube changed after the first 500 miles to assure differential integrity over the life of the vehicle. AMSOIL Synthetic Gear Lubes provide superior protection and performance for differentials following the break-in period, saving motorists money through extended drain intervals, while also costing less per quart compared to many competing OEM gear lubes.

Read the full link for yourself.
http://www.1st-in-synthetics.com/change_gear_lube_after_break_i n_period_for_long_differential _life.htm

[Marauderjack]

When you buy a new car the gears are not "Broken In" and you are not required to change the differential fluid for 100K miles!!:cool: No special treatment as far as I know??:shake:

Why is a rebuild different from factory OEM unit??:confused:

If the differential is set up right why not just drive it like you intend to??:rolleyes:

Inquiring minds want to know!!:D

[rayjay]

There is no filter, but there is a magnet. Mine had a very minor amount of particulate on it from the OEM gears. My guy suggested Royal Purple gear oil and we used the MotorCraft friction modifier. He said he had seen problems when it was not used with the gear lubes that claim it wasn't needed. It also was supplied with the new clutch pack for the LSD. The 1st thing he had me do was go to a large parking lot and drive figure 8s to set the gears IF they needed it. They didn't, but I did as instructed. As I stated before, he is a Ford factory instructor.

[CKMustangCobra]

why would the gear whine be heard under neath the hood?

Metal is a good conductor for sound/potential energy among other things.

The rear end noise and easily use the metal parts to tranfser a noise throughout the car.