Sounds Like my differential is Gone

Hey guys i dont know anything about differentials but my car has been making this horrible metal crumbling noise every time i try to accelerate even softly from a dead stop. I also makes like a crying or humming noise while im driving steady at 60. Im guessing its my differential.
Am i correct?
If so wats the best way to fix this ( Bum a diff of a junk yard, rebuild the one in there, or Upgrade)?
Give some price guesses at what these things could cost...
Most importantly i know that if iget anew one or used one i can install the whole thing, i know that if i rebuild im going to have to pay some clowns, but i dont know about the upgrade ive read things around here about you guys installing geras how those that work.
I want a strong differential that will last and eventually could handle about 400-500 RWHP. What should i do.

Best way to tell whats going on is to open her up. It could be something as simple as old fluid or it could be a chipped gear or a bad bearing. My money would be on either a bad pinion bearing or chipped ring gear.

Great...is my car driveable like this?

Do these cars have a plug or do i have to remove the entire cover?

Anyone else have any opinions?

How dificult is it to replace either one of those things formula lt1

I don't think its all that difficult to install a differential or ring gear but due to the fact its a very accurate adjustment requirement. You have to make sure you don't screw anything up or you will find yourself replacing the whole rear end assembly. Thats why either watch a professional do it the first time or pay someone to do it. Also, yes you need to remove the cover. The plug will show you nothing but if a lite fluid drip. I was driving around my Formula for like 2 -3 months with a rear whine and clunk from take off which turned out to be a chipped ring gear. It was a little annoying but nothing major happen but something major could happen if that chipped piece of metal found its way into a bad spot. So the sooner, the better.

ok how do i make differential strong enough to hold more power what is that i would need to replace? And around how much would it run me. I dont want to fix a gear and have to fix another in a few months.

Auburn and torsen i heard they are differetials how much do they run for or where can i check for prices.

Also what do you guys recommend.

I put a Torsen in my Formula due to them being the strongest limited slip unit available for our cars. You can usually pick up a torsen for around 250 - 350 from a salvage yard but a auburn is plenty strong and the super small ring gear is whats going to be the problem anyway. It all depends on the area what a differential/Ring & pinion install runs. I would say a rough ballpark is in the area of 250 - 300 but have heard of people geting it done for as cheap as 150 in labor or as expensive as 600. So you really have to call around.

sounds like a pinion bearing went out, then your gear & pinion got damaged ... unless you did a big burnout and when it hooked you heard a loud pop ... then its a broken diff case. lets just say I know a little about axles ... If you do it yourself make sure you get the correct gear mesh or you will be doing it again. I'll try to keep an eye on this post. see if the pinion moves where it connects to the driveshaft!

alright guys thanx alot ill keep u updated.
Im going to check the driveshaft movement but if it is that im probably going to have to pay for a rebuild or....
Tommorow im going to call a few junk yards and check prices do you guys know of something i should ask for.

if your going to call junk yards to get a new axle, you will need to know what ratio you have ex... 3.56 : 1 , or 4.10 : 1 (spoken as 3.56 to 1 or 4.10 to 1). The other thing is you will have to make sure you get a limited slip diff (posi), not an open differential (one wheel peel). (all info stamped on tubes, or stickers on tubes, or metal tags on diff cover bolts)

my suggestion ... go to a parts store and get a cover gasket (if used), silicone gasket sealer, the proper gear lube (usually 80W90) and friction modifier (if you have a posi (limited slip differential)).

If you know anyone with a car lift become friends with them and borrow it, if not jack up the back end of the car, put jack stands under it to make sure its safe (don't forget to block the front wheels), pull the drain plug near the bottom of the carrier (big cast part that holds the differential) to drain the fluid (might not have a drain, but I think that one does). Pull the 10 bolts that hold the diff cover on, and see whats going on inside there. Check the big gear for missing teeth or broken teeth, look at differential (piece that gear is mounted to) to see if its broke (usually near the pin that hold gears inside diff), and check for bad bearings on the pinion (flange mounts to the pinion, then drive shaft hooks to the pinion).

Even if you do nothing but see whats wrong and get any pieces out of the bottom of the carrier, seal it back up, and replace the fluid (if it has a posi (limited slip) make sure to add the friction modifier to the fluid or you will be replacing the posi), you extend the life of it, now you know whats wrong so you don't get cheated at a shop. You didn't actually mess with any of the shims or throw anything out of adjustment, you were just inspecting it. While you have it open take some pics with the diff & gear in differnt positions and I might be able to tell you what the problem is, if its not obvious to you.

If its bad gears it should be cheaper to have it fixed then to buy a junk yard axle ... If I were you i'd just have whats bad fixed, that way you know what you have, and your not waiting for a junk yard one to fail like yours did ... just my :2cents:

Hey Gmack thanks alot im going to try to do that this weekend. the reason im going to try to call yarsd is because i want something stronger. If I fix this it will only be a matter of time before another thing in there breaks. Ofcourse money is always an issue but thank you now i know what is in there and what to look for.

hey guys ive been calling yards and they have stock in "good" condition for 450. And no one has the auburn or torsens do u guys know were others have gotten theirs.
im also going to ask for some appraisals on rebuilding the diff now...

Good luck finding an aftermarket diff in a junk yard ...

try Ebay, Jegs, Summit, ftpp.net, lmperformance.com, ect ....

I wouldn't buy anything until you know whats bad though ....
before you buy one you will need to know your gear ratio (rear end gear ratio), and if your planning on having a shop install it check their prices & find out if they will install one you buy, before you buy it, if their prices are close to what you can buy it for let them deal with it, that way if they don't get the right one they have to deal with it!

by the way, you can upgade your diff for about the same as the yards your calling want for a stock one! also compare the torques they are rated at, and get the one that best fits your driving style (drag strip, road courses, street driving) they all take different differentials and you will not be happy with the street preformace of a drag strip differential.

alright man thats awesome info...if i get the whole dif i can install it myself i just cant fix anything inside of one.
Well i would like a diff that is fit for road courses.
Let me ask you something now that u mention this how would i go about upgrading my dif.
I live in miami if i go to a shop and tell them i want a rebuild but upgraded They will charge me more and only put stock or even cheaper shit in their.
This is why i need to know alot before i even show up and make myself a victim.
I will take it apart this weekend and find out whats wrong, then when i go to a shop i need to let them know i want to upgrade but i want to know exactly what to ask them for.