Mach 460 and differential problems

atomic_stang · 11-17-2003

Just bought a '99 GT with 5 speed and I'm diggin it. Got a few problems though.

First, my Mach 460 audio sounds like sh--. Not so loud volume, high treble and zero bass. I've heard Mach 460s before and I know they'll make your ears bleed, so evidently mine has a problem(s). All the amps and speakers are in place. Could it be the sub amp is blown? the speakers? I dont hear any buzzing. Are blown amps/ speakers common on these systems?

Second, something in my driveline is making a whining noise and it seems to be coming from the rear (no, my girlfriend doesnt ride back there

). This is pretty damn annoying. This car has 68,000 miles do these diffs wear out that quickly? The car doesnt appear to be abused and has the original 3.08 ratio. I'm getting ready to put in a set of 3.55s so I dont care to replace it, I'm just curious if there is a known Ring/pinion or bearing problem with the stock stuff.

Thanks for your input!

97GTstang · 11-17-2003

well the mach 460, not to seem like i am mentioning the obvious but did you check the bass level and treble level, and balance and stuff like that??

as far as gears go, it is common to get a little gear whine. I get gear whine when i spin my tires but not at normal driving. Do you get it at normal driving or what? Also going from 308 to 355 is kinda a waste if you are doing it for performacne purposes. I would consider 373 or 410's. I myself am planning to go with at least 373's possibly 410's.

Mana4Real · 11-17-2003

On my mach 460 I can change where it sounds the best. It's in your menu. Give that a shot too.

samGT · 11-18-2003

Check the fluid level in the Diff. Just get up underneath and take a 3/8ths inch ratchet with the extension and pull out the screw/plug. The plug is the female end (ratchet is the male end). The plug is on the drivers side of the differential "pumpkin" and is just to the top right (from under neath the car facing the rear) of the driveshaft. Once the plug is out, and it can be hard to get out, just stick your finger in and see if the fluid level is at the hole line, you can feel it. If not you are low and need to add some. With 68K though if there was damage then more fluid might not mask the sound that much.

With under 20K mine started to whine. It just kept getting louder over time. It started at 8K. The lady at the ford place said when the mechanic pull off the diff cover everything just fell out. The bearings were scarred and everything was "burnt." Apparently, from the factory sometimes depending of what time of day and who built the diff they don't always put enough gear lube and diff fluid in. The same thing happens with the transmissions (there was a notice from ford, I think, that went out about the low tranny fluid, might have been consumer reports though, I remember it from somewhere. Anyway, luckily I was under warranty at the time. They said they said that the parts and labor was over 1000 dollars. Also, if I had not come in then I would in the very near future have been riding, possibly on the interstate, when my diff locked up and locked down my rear sending me spinning.

It is not that hard to check and could save you 1000 bucks. Put it up on ramps, jackstands, or even a curb works (I used to do that before the ramps.) Man, that was alot of typing. Good luck I hope you arent too low that the noise wont stop.

If you do add more fluid dont forget the friction modifier it also lowers the whine. sam

brys66stang · 11-18-2003

I was talking to a mecanic and he said that after a while the friction mod. wears out and all you need to do is to add 1-2 bottles of friction mod.and the do alot of turns both left and right to get the friction mod. back into the cluchpack. and the noise should go away. but if you plan on changing the gear ratio I would just wait and then put 3.73 or 4.10's in. I put 3.73's in and love them and at 80 I only run 2500 rpm.

atomic_stang · 11-19-2003

Thanks for the quick responses guys.

Since it's been raining here all week I havent had a chance to check my diff and trans fluid so I'll have to wait till this weekend.

As far as the Mach 460 problem goes:

-I've tried every setting bass, treble, fader, balance but nothing improves the sound.

-I checked all my fuses at my fuse block and none appear to be blown. Is there another fuse in the system somewhere??

-I unplugged the rear amps ( the forward most plug) one at a time with the sound system on and the fader all the way to the rear and it didnt seem to make any difference.

Anybody ever heard of these amps being blown? I've got a good used set coming in on Friday I'm gonna try.

MJD02GT · 11-20-2003

Quote:

Originally posted by samGT
Apparently, from the factory sometimes depending of what time of day and who built the diff they don't always put enough gear lube and diff fluid in.

I'm glad somebody said it!! You can thank the Unions for that. Damn Unions

My Uncle bought a new F150 years ago, and had a rattling noise around the front driver-side door. After the third time in to the third dealership, they pulled off the door panel and found a coke bottle lying in the door with a note inside that read, "Bet it took a while to find this."

My 460 has a cracked front woofer. It happened about a month after I bought it. Although, it only sounds really bad when the music has a large, heavy bass. The speakers could just all be cracked. Take it to an auto stereo place, where they install them, and ask them. They should know.

atomic_stang · 11-23-2003

Got my replacement rear amps for my Mach 460 and installed them. Success! Sounds pretty darn good. May have a fluttering speaker when I crank it but not sure. Seems the drivers side was the culprit and affected the whole system. I replaced them both though. Wonder why it went out? Heat, vibration?

Checked my differential fliud and it was full. My dad has rebuilt several hundred 8.8 diffs and he seems to think its a pinion bearing. As soon as my gear gets here, I'm gonna go through the whole unit....Just to be sure!

mmills421 · 11-24-2003

Where are the stock amps located at? I have some "issues" with the way my installer put in my amp and subs in the trunk. I had 2 8" subs that hit harder than the 2 10" subs I have now. I think he might have ran the new amp right off of the stock amps instead of putting in all new wires. He said he didn't, but I'm going to check...

atomic_stang · 11-24-2003

I'm no expert on these systems since I've only had my car 1 week but I'll tell you what I've found out so far.

There are 3 amps in the 460 sound system. One amp is up front forward of the shifter and the other two are identical and are mounted under a housing that also hold the 4 rear speakers. I attached a pic but you cant see the rear amps in this picture. (Photo courtesy Some dude on Ebay

)

By the way, if someone needs to change out the rear amps, just remember to have a T30 Torx bit handy. There are four screws holding each amp.

mmills421 · 11-24-2003

Thanks man, but I forgot to mention mine is convertible...the speakers are mounted differently. I'm going to rip it apart over the holiday and see what I find..

GTron · 11-24-2003

[ The car doesnt appear to be abused and has the original 3.08 ratio.

All 1999 and up Mustangs came with 3:27 gears whether they be V-6, V-8 , EAOD or 5 speed. Mach 1's have 3:55 gears. If your car does indeed have 3:08 gears in it, that could be the source of the whine. The ring and pinion may not have been set up properly by whoever installed them.

2000BlackGT · 11-25-2003

Quote:

Originally posted by atomic_stang
The car doesnt appear to be abused and has the original 3.08 ratio. I'm getting ready to put in a set of 3.55s so I dont care to replace it, I'm just curious if there is a known Ring/pinion or bearing problem with the stock stuff.

Thanks for your input!

Unless you plan on road racing I don't think that you will notice a difference going from 3.27s to 3.55s. I have 4.10s in mine and juts love it. I still get about 21MPG on the freeway too. 3.73s to make it at least somewhat worth it.

atomic_stang · 11-25-2003

So I have a 3.27 ratio?? I'm pretty sure it's stock that's why I said it was a 3.08, I dont know for sure. I didnt know 99 ups came factory with 3.27s thanks for informing me. Let's assume then that it's a 3.27 until I find out for sure this weekend.

Newbie question: Do these cars also come factory with a bare metal diff cover? It might be chrome, it might be aluminum not sure, but its certainly bright metal. Could this be a clue my gear was changed at some point and improperly set up leading to noise? I noticed the cover as I was checking around the diff for signs of leaking, thinking low fluid may be the reason for the noise. The local oil change dude checked my fluid (for free! Thanks greasy dude in a hole! :thumbsup ) or I would have checked the tag on the diff. They still have tags on the diffs dont they?

HMMMMM. Going from 3.27 to 3.55 wont be a noticeable jump now will it? Maybe I'll go ahead and install a 3.73. It's just that this is my only car and I have this persistant fear of 10 MPG and continued gear noise. It might seem like I'm making a big deal out of this gear noise issue, but honestly, it's so loud, especially when cold, that it makes my ears ring after long drives. Even over the radio. Thats my main reason for changing it out right away.

Anybody else miss the good ole days of 'stumps' or 'pumpkins'? When you could keep different ratio assemblies around the garage and change em out in about an hour? Life was good.

bgt98 · 11-25-2003

First thing I did when i got my mustang was change out the mach 460. Nice for a stock system, but if you want some bump, put in a new head unit. EQ in the head unit is really fuzzy. Also, bypass the mach 460 amps if you get a new head unit.

The amps in a convertible are located behind the back seat underneath the canopy . They are located on either side of the canopy motor.