JTB737

Okay, So I have a 1999 mustang gt auto completely bone stock with 45k on her.. The rear end is extremely annoying... and gear whine from what I understand is is like the whine you hear when in reverse? Correct if wrong. I took it to a dealer figuring maybe they could atleast tell me whats going on... They test drove it and told me they think it's the clutch packs and that it may need gears. They quoted me 3 GRAND TO FIX IT! At the point I was pretty upset that they'd even try to pull one on me so I had them change the dif oil and on my way I went. I do believe it has gotten a little better with the new fluid.


The sound is like a metal rubbing sound.. I hear it alot more on decel. I don't believe it's the clutch packs though, because the LSD WILL lock up. and will do it consistently... Any other way to see if it's the clutch packs gone bad?

It's not a consistent hum or anything more like the wa wa wa (helicopter like) you get sometimes if you have only one window open... but quieter and a little metal scraping... sorry for the horrible description..

Also, the car does it in neutral. The car still drives like it's brand new. it's just loud..

Where do you all think I should start to chase this problem at? It drives me nuts! axle bearing? new gears? carrier? could it still be the T-lok?

I will be doing all the work myself...

Thanks for all the help once again!

Fizzics Boy

You can start by changing the fluid if you want. It could be broken down or there just might not be enough in there. Thats where I would start if I were you, and if it doesnt work then I would look into other causes.

0949er

you could always drain your diff and then open the cover up and physically inspect the gears for damage and any possible issues while you are in there. That is where I would start.

Fizzics Boy

+1 Check to see if there are and chips, cracks, or uneven wear in them, especially the coast side of the gear since you said it is making the most noise on decel. Also put new fluid in there as well when your all done like I said. I use redline synthetic since it was half the price of Royal Purple and also comes with the friction modifier mixed in already.

trailor

also, when you drain/fill the diff., add in a bottle of friction modifier. i had to get my bottle of it from the dealer, & was under $10 i believe. but anyway, really helps out. the annoying diff. "clicking" noise when making a slow/hard turn has been very surpressed since i did that

devongarver

He said they already changed the dif fluid guys...

OP, you say it does it in neutral, is this neutral while parked or while coasting or what?

The noise you are describing doesnt even sound like your differential, it sounds more like a bad bearing to be honest. So check any type of bearing in the back. Axle bearings and wheel bearings will do that. I have an idea if you have an empty parking lot and a brave friend lol. Have him lay in the trunk while you drive slowly through an empty lot and see if he can hear which side/direction the noise is coming from.

MidNightRunner

+1 on the bearing so put the car up, make sure that all the nuts are tight first and then try to wiggle each tire. Hold the wheel at 12 AND 6 then 3 AND 9 and see if there is excessive play. If your not sure take it to a tire shop and ask them what they think.

JTB737

Yea, I think it's a bearing.. and yes it does it in neutral while coasting. When sitting still it's perfectly quiet. I had my uncle drive it down the road while i was in the trunk (we live in the desolate arizona desert so no one else was on the road) and it just sounds like its coming from the axle. Which we've already pinpointed. the interior and all the metal from under the trunk pads really dispearses the sound... I almost need to ride under the car on the crawler and see what I get ;D. Justin kiddin. The wheels don't have any excessive play, how hard is it to change the axle bearings? I think that's where I'll start..

WhiteFoxGT

Yank the axles out and check right on the ends for wear. Even if you replace the axle bearing and the surface on the axle (that rides on the bearing) has ANY kind of scratch or groove, its trash.

I just did dimebag's car Saturday. you shoulda seen what those axles and bearings looked like.

sinister99GT

i had to rebuild my 99 rear end at around 50,000.both axels were burned at the bearing, loud and anoying. the ford dealer i bought it from rebuilt it and it has been good since110,000 no noise.