rear differential is shot

scupking

Active Member
Sep 18, 2005
1,186
1
36
Enfield, CT
Well, I brought my car into the local garadge to have a new drivers side tie rod put in. They where looking over other parts of the car and said that I need a new rear differential. The fluid is all black and metalic. What the heck should I do? They said it would be four hours of laber plus the part cost. I think this might be a good time to get some gears if they are going to put in a new differential. How much would this all cost?
 
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im not 100 percent sure but if the fluid has never been changed it would make sense that it is black and metalic...due to the clutch packs in the diff wearing as you drive...if you are not ready for the gears yet ask them to just change the fluid and put new additive in and tell them you would like to see it when the cover is off to check for metal chunks. if you have felt nothing and heard nothin the is a pretty good chance that there is nothing wrong.
 
im not 100 percent sure but if the fluid has never been changed it would make sense that it is black and metalic...due to the clutch packs in the diff wearing as you drive...if you are not ready for the gears yet ask them to just change the fluid and put new additive in and tell them you would like to see it when the cover is off to check for metal chunks. if you have felt nothing and heard nothin the is a pretty good chance that there is nothing wrong.

The only thing I have noticed is my stock gears are making a good amount of noise. Other then that it feels normal.
 
yeah then i would have them pull the cover when you are there and look for big chucks of metal or teeth missing or worn badly on the ring and pinion gears. i dont think its truely blown up. i think they are makin things out to be alot worst than they are. how many miles are on the car?
 
If the stock gears are whining they could have heated up and possible to keep whining even after changing the fluid.

My rear is shot as well and still working out what I want to do :)

31 splines and posi is a lot of money.
 
that milage seems kinda low for the rear to blow...but if they arnt pulling your leg there could possibly be enough metal to make there bearings whine...if you are not ready for the gear swap yet just have them drain it and put new fluid in with additive(very important) and listen to it. if it gets louder its time. if not you should be ok for a while.
 
sounds like the clutches are worn in your stock diff. not terribley bad, you could drive on it for a lil while if you had to, but no performance driving for you. i could stand that my diff wasnt performing as it should when mine went at ~52k, so i replaced everything. 31 spline axles, torsen t2 road racing diff and new bearings. parts should cost you around 1k. ive seen labor anywhere from $500+. 4hrs labor isnt too bad actually. thats less than $400. its up to you
 
I drove my stock rear for 140k. Then rebuild it using some used parts and it wasn't to bad.

used rebuilt 31 spline explorer diff about $100
used 3.73's $35
usa alloy 31 spline axles with new bearing and wheel studs $205
ebay bearing seal and shim kit $100
fluids $20
labor $310
------------------------------------------------------------------
$770.00 for a 31 spline set up with gears complete and installed.
 
I drove my stock rear for 140k. Then rebuild it using some used parts and it wasn't to bad.

used rebuilt 31 spline explorer diff about $100
used 3.73's $35
usa alloy 31 spline axles with new bearing and wheel studs $205
ebay bearing seal and shim kit $100
fluids $20
labor $310
------------------------------------------------------------------
$770.00 for a 31 spline set up with gears complete and installed.


i always heard that buying used gears was like buying someone elses underwear, you just dont do it
 
I went to the shop yesterday and asked them what was going on. I then told them, well I guess its a good time to upgrade to posi. He said you "already have posi and its not working"? I didn't think our cars came with posi? Granted 2 People had my car before I bought it, so anything is possible but I don't belive them.
 
I went to the shop yesterday and asked them what was going on. I then told them, well I guess its a good time to upgrade to posi. He said you "already have posi and its not working"? I didn't think our cars came with posi? Granted 2 People had my car before I bought it, so anything is possible but I don't belive them.
TracLok is posi when it is working properly.
 
I went to the shop yesterday and asked them what was going on. I then told them, well I guess its a good time to upgrade to posi. He said you "already have posi and its not working"? I didn't think our cars came with posi? Granted 2 People had my car before I bought it, so anything is possible but I don't belive them.



All V8 Mustangs since the mid-80's have had Posi...aka Traction-Lok. Both are a form of a limited slip differential. GM calls theirs Posi-traction (aka Posi) while Ford calls it "Traction-Lok" (T-lok for short). They are basically the same thing.

So yes, your car came stock with a limited-slip style rear end.

If you were having a tie-rod done, what were they doing poking around inside the rear end?? Sounds to me like they were looking for more work to get you on.
 
thats exactly what i was thinking but i figured maybe he knew them and trusted them :shrug:

Yeah it’s a little shop down the road that we have used forever. I wanted them to also fix my passenger side wiper sprayer last week and they cracked that plastic peace (I don't no the name of it). They are going to replace it obviously for free. I know they blew one of my speakers on my old car. They also fired a guy a few months back because he tried to scam people by saying that almost every car that came in need new transmission fluid.