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Fredensborg
07-30-2011, 11:13 AM
How difficult is it to install/repair a limited slip differential? I guess I'm not even sure if my Mustang has one or not (1973), but it's a one wheel wonder, and I would like to be able to do proper burnouts with 2 bad ass strips of rubber! :3gears:Do I need to replace the whole axle? Or is it just the ring gear? Or is it something simpler? Any help would be greatly appreciated!:burnout:

MadJack
07-30-2011, 11:26 AM
usually you can look up by axle code/ tag if you already have ls. but to get one installed all you need is the center section. what rear end do you have?

Fredensborg
07-30-2011, 11:31 AM
I'm not home right now so I cant check,I believe it's a 9 inch with 3.73 gears? I could be wrong though. I will check later tonight and let ya know. Where do I look for the axle code/tag?

MadJack
07-30-2011, 12:02 PM
on the vin tag on the door, or there should be a tag attached to the axle housing. a ls set up for a 9" can be had cheaply

Fredensborg
07-31-2011, 05:43 PM
So here is a pic of the tag on my diff. After doing a little research online, it appears that it is a 9 inch, non-LS diff with 3.25 gears. Lame. I don't know if that is an ok ratio or not but I would like to make it a LS. Do I need an entire new rear end? or is there some gizmo I can put in the pumpkin that will magically make it LS. Oh, and it has 28 splines if that helps.

MadJack
08-01-2011, 05:47 AM
you do not have to replace the whole rear end. the 9" is the most famous and therefore most parts in the aftermarket for it, go onto summitracing.com or jegs.com or even ebay and you can find ls parts and gears that you put onto your third member, or you can buy a whole third member with the gears and ls you want. those gears arent amazing, there more highway gears, maybe some 3.73's would do well for you.

Fredensborg
08-01-2011, 09:11 AM
Thanks for the info! I'll look on Jegs later today and see what's available. Although I may have to wait awhile to upgrade the gears, I'm sure it's expensive. Just so I'm sure, the higher the gear ratio, the better jump off the line you get but you lose top speed correct? Is there a big difference from 3.73's to 4.11's? How high to gear ratios go?

MadJack
08-01-2011, 11:52 AM
a carrier needs to be changed once you get to a certain higjth of gear. but ya, higher ratio better jump with less top speed.,i like 373's cause they have always done what I needed

FLSTCI71
08-01-2011, 11:54 AM
If you've currently got 3.25s, then 4.11 is a big jump. If you also have the original C6, then 4.11 will make your Stang almost undriveable. I have them in my 69 Torino with the C6 and I can tell you, it is not a road trip car. 4.11's without an overdrive basically make a car good for stoplight cruising. I think (I am not 100% sure), but I think 3.50 is about the deepest gears Ford usually put in their automatic equipped cars in the early 70's. It was in 69 anyway. You need to decide what your primary use is going to be, highway driving, drag racing or a combination. Obviously, any combination would involve compromise. If your car is stock now, I would recommend sticking with the stock gears or maybe, as mentioned, the 3.73s.

Fredensborg
08-01-2011, 12:53 PM
If you've currently got 3.25s, then 4.11 is a big jump. If you also have the original C6, then 4.11 will make your Stang almost undriveable. I have them in my 69 Torino with the C6 and I can tell you, it is not a road trip car. 4.11's without an overdrive basically make a car good for stoplight cruising.

It does have a C6,what do you mean undriveable? Does it decrese top speed that much? Or it just makesit too jumpy? Sounds like 3.73's may be the way to go. But judging from the prices I just saw, it's gunna be awhile before I get to replacing the gears, 1,200$ and up for a complete 3rd member with higher limited slip gears! I tried looking to se if there were any Detroit lockers for my model year but they dont seem to make them for 71-73 Stang's?Or do I just need to find one that says its for a Ford 9" with 28 splines?? Those were cheaper (500$ range) I could probobly swing that.

FLSTCI71
08-01-2011, 05:04 PM
It does have a C6,what do you mean undriveable? Does it decrese top speed that much? Or it just makesit too jumpy? Sounds like 3.73's may be the way to go. But judging from the prices I just saw, it's gunna be awhile before I get to replacing the gears, 1,200$ and up for a complete 3rd member with higher limited slip gears! I tried looking to se if there were any Detroit lockers for my model year but they dont seem to make them for 71-73 Stang's?Or do I just need to find one that says its for a Ford 9" with 28 splines?? Those were cheaper (500$ range) I could probobly swing that.

What I meant was if you have 4.11s with a C6, you'll be taching 3500 or higher on the highway. That would get really old in a hurry. 3.73s would be a good compromise. Mine had 3.50s stock and those were pretty good. When I rebuilt the motor, I wanted more gear, so I went with the 4.11s. It's been great for my use, but may not be for yours.

The Traction-Loks and Detroit Lockers are all fine for your car. A 9" is a 9", so either would fit in your housing. The main thing, as you mentioned, is 28 vs 31 spline. Mine is a factory CJ car, so it came with the 31 spline axles and I'm running a Detroit Locker. I don't baby it and it's been rock solid since I bought the car a "few years ago". Okay, since 1978. lol.

Fredensborg
08-01-2011, 05:24 PM
Sweet! thanks for the help,now I just need to hide about 500$ from the wife so I can buy my part!! I also found this: http://www.jegs.com/i/Powertrax/754/1810/10001/-1http://www.jegs.com/images/photos/700/754/754-1810.jpg It's not a "Detroit Locker",but it is considerabely cheaper. does it do the same thing? For now my only concern is being able to a proper burnout, the one wheel wonder has got to go.

Fredensborg
08-01-2011, 05:26 PM
What I meant was if you have 4.11s with a C6, you'll be taching 3500 or higher on the highway. That would get really old in a hurry. 3.73s would be a good compromise. Mine had 3.50s stock and those were pretty good. When I rebuilt the motor, I wanted more gear, so I went with the 4.11s. It's been great for my use, but may not be for yours.



Do you drag race that Torino? sounds like a nice car, I think a pic is in order!

FLSTCI71
08-01-2011, 06:29 PM
Do you drag race that Torino?

It's seen some stoplights over the years. :takeoff:

MadJack
08-01-2011, 08:33 PM
alot of guys run power trax and have never heard complaints

Fredensborg
08-02-2011, 03:45 PM
It's seen some stoplights over the years. :takeoff:

Beautiful car! I want to see it in person, you take it out for club events ever??


alot of guys run power trax and have never heard complaints

Thanks FatGuy!! I just might go that route then. It was about half the cost of a Detroit Locker, and if I plan on replacing my 3rd member in the future then I might as well not spend more than I have to on this one.

FLSTCI71
08-02-2011, 07:36 PM
Beautiful car! I want to see it in person, you take it out for club events ever??

Thanks. No, I don't show it, just cruise it around town once in a while. I just had a Police Interceptor intake ceramic coated and had some snake valve covers powder coated, so I need to pull it apart and get those installed. Maybe this winter....

Let us know what you decide on the rear.

Fredensborg
08-11-2011, 04:28 PM
on the vin tag on the door, or there should be a tag attached to the axle housing. a ls set up for a 9" can be had cheaply

How cheaply could I find a ls setup?? Any good spots to look? I am having trouble finding any for sale. Would it be cheaper to buy someones used rearend or to buy a locker for mine? Eventually I'd like to get lower gears anyway

brobber01
08-11-2011, 04:52 PM
I don't know if it would be limited slip, you would have to call and check, but 9in bronco rear ends can be had cheaply from junk yards.
http://car-part.com/cgi-bin/search.cgi?userSearch=int&userPID=1000&userLocation=All+States&userIMS=&userInterchange=%3F%3E%3D%3DR&userSide=&userDate=1985&userDate2=1985&dbModel=27.33.22.22&userModel=Ford%20Truck-F150&dbPart=435.1&userPart=Rear%20Axle%20Assy%20%28%20RWD%29&sessionID=200000000000000000397283665&userPreference=zip&userZip=55362&userLat=45.2795&userLong=-93.7941&userIntSelect=407297&userUID=0&userBroker=&userPage=1&iKey=

Fredensborg
08-11-2011, 04:56 PM
Hey thats a pretty cool site! Thanks!