'86 Rearend question

[Darrin]

O.k my fellow FOX RODDERS...Question! I have a chance to pick up an '86 rear end for my '93. It has the tag of 3P08. I know this is to indicate it is posi. My question is: What type of posi? Is it a spool or a locker. For $100.00 I am not going to let it pass but, I was just wondering before I got it.

 

[93 LX]

if its an 86 Mustang or Capri then its a trac-lok with 3.08 gears.

 

[Darrin]

Are these any good? My car won't see more than 300-325 Hp but, for the price I like the posi.

 

[85_SS_302_Coupe]

Most likely a 3.08. It's a pretty good rear end for being stock but you'd be better off getting the gear out of a Tbird turbo coupe rear end which is either a 3.55 or 3.73 depending on the trany.

 

[93 LX]

Are these any good? My car won't see more than 300-325 Hp but, for the price I like the posi.

Well the GT500 uses a 8.8 trac-lok. A D-locker or Auburn may be better just make sure you rebuild the one you are going to use.

 

[Mustang5L5]

Hate to break it to you, but the axle code for a Trac-lok rear is 3L08.

The L is the letter which indicated the limited slip differential.

I don't know what P refers to. What did this rear end come out of?


It's a limited slip differential, not a spool or locker. Posi is a GM term, so ford wouldn't use it on theirs. Their name for it is "Traction-lok"

 

[NKau]

O.k my fellow FOX RODDERS...Question! I have a chance to pick up an '86 rear end for my '93. It has the tag of 3P08. I know this is to indicate it is posi. My question is: What type of posi? Is it a spool or a locker. For $100.00 I am not going to let it pass but, I was just wondering before I got it.

If your '93 is an original 5.0 car, you already have a posi/trak-lok.

 

[Darrin]

Over the years I was told there are 3 rear ends. Open (one tire spins no matter what), Limited slip (one tire spins unless traction requires both) and Posi (both tires spin no matter what). Therefore you can't truely have a posi unit if it has a limited slip. Now I jacked up the rear and spun the tires. Both tires spun at the same time in the same direction hense (posi, short for positive traction locked differential) limited slip will spin one tire in one direction and the other in the other direction when jacked up. I read one time in 5.0 magazine once that the '86 5.0 mustangs came with a TRUE POSI rear differential not the generic term given to the Limited slip rear. I tried like hell to find that copy in my 8 boxes of saved magazines but, no avail. Ford confirmed the "P" in the tag did truely mean a posi rearend. example 3O08 is 3.08 open rear, 3L08 is 3.08 limited slip and 3P08 is 3.08 posi. Unless the Ford parts guy is a Gm guy they stated it as Posi. I had an '86 mustang vert about 6 years ago and it had the same tag and when I turned tight corners the rear would shift the car sideways a little because the rear was posi. Now I never pulled the rear apart to see the internals so I didn't know what the posi unit was. My brother put a full spool in his and it acted the same. Yeah I could dump $500.00 dollars for a locker for mine and get the clunking associated with the posi lock up, or put a full spool in and spend 500.00 redooing the rear at the same time or get an '86 posi rear with 75,000 miles for $100.00. I just didn't know how strong they were.

 

[Mustang5L5]

Over the years I was told there are 3 rear ends. Open (one tire spins no matter what), Limited slip (one tire spins unless traction requires both) and Posi (both tires spin no matter what). Therefore you can't truely have a posi unit if it has a limited slip. Now I jacked up the rear and spun the tires. Both tires spun at the same time in the same direction hense (posi, short for positive traction locked differential) limited slip will spin one tire in one direction and the other in the other direction when jacked up. I read one time in 5.0 magazine once that the '86 5.0 mustangs came with a TRUE POSI rear differential not the generic term given to the Limited slip rear. I tried like hell to find that copy in my 8 boxes of saved magazines but, no avail. Ford confirmed the "P" in the tag did truely mean a posi rearend. example 3O08 is 3.08 open rear, 3L08 is 3.08 limited slip and 3P08 is 3.08 posi. Unless the Ford parts guy is a Gm guy they stated it as Posi. I had an '86 mustang vert about 6 years ago and it had the same tag and when I turned tight corners the rear would shift the car sideways a little because the rear was posi. Now I never pulled the rear apart to see the internals so I didn't know what the posi unit was. My brother put a full spool in his and it acted the same. Yeah I could dump $500.00 dollars for a locker for mine and get the clunking associated with the posi lock up, or put a full spool in and spend 500.00 redooing the rear at the same time or get an '86 posi rear with 75,000 miles for $100.00. I just didn't know how strong they were.

Dunno where you got all that but it's not exactly true.

There are only two rear ends. The base model 2.3's and later base V6's got the open differential.

All V8 models got limited slip type differentials. In fact 1986-2004 is basically the same 8.8 rear end. You can take parts from a 2004 and use it in the 1986 rear end.

There is no spool or locker and Posi is a GM marketing term for a limited slip differential. Ford's marketing term is "Traction-lok" They both refer to the same thing but Ford would never internally call it "Posi" because it's trademarked. People interchange the two terms all the time because they are both types of limited slip differentials. There was never a factory spool or locker in a 1986+ Mustang

The only options concerning the rear ends of 1986+ V8 Mustangs was axle ratios....2.73's 3.08's, 3.27's etc. There was no optional locker unit at all.

The axle codes for those rears are 2L73, 3L08, 3L27, 3L55, 3L73. They were also used on t-birds, broncos and f-150s with the limited-slip differential.

I can't even find reference to a 3P08 rear end anywhere. You sure it's a P?

 

[rd]

If it is a tractionlok, it should be labelled 3L08, indicating a 3.08:1 traction lock axle.

Not to be tacky, but there are only 3 major types of limited slip differentials in common use, the clutch type like a Ford Traction lok, the cone (or cone clutch) type, like some Auburn units, and the worm gear type like a Torsen(sp?).

A locker is basicly a clutch type using dog clutches.

A spool is a solid connection between the left and right axle shafts.

I love the ongoing learning process we all go through. I remember when I learned about full race radiator caps!

 

[NKau]

Yeah I could dump $500.00 dollars for a locker for mine and get the clunking associated with the posi lock up, or put a full spool in and spend 500.00 redooing the rear at the same time or get an '86 posi rear with 75,000 miles for $100.00. I just didn't know how strong they were.

You already have a posi. If you jack your rear up, and only one wheel turns, it's because the clutches in your current trak lok are worn out. It's very simple to rebuilid the ford trak lok, and the ford rebuild kit only costs $50.

http://www.angelfire.com/theforce/5ohcpa/cpa5ohtech018.htm

This is a very good DIY tutorial on how to rebuild yours. The factory units can handle a decent amount of power, and are infinitely rebuildable. Many use an 'alternate stacking method' when replacing the clutches/plates and shim the unit a little tighter.

 

[Darrin]

My axle is fine. Yes it definately is stamped "P". Like I said turn one wheel and both wheels turn the same way. On mine that is listed with a "L" I turn one tire and the other turns the opposite direction. Limited slip. The Ford guy said it was not a limited slip. If it was it would be listed as an "L".

 

[Mustang5L5]

Well i don't know what that Ford guys was on but he's definitely not right.

There was ONLY limited slip on the Mustang.

If it's not limited slip then it's open.


Nothing else was available. Only those 2 options.


POSI is Limited slip. There is no difference. Posi is just a trademarked name. Ford can't use it. It would be like Ford calling it's Cobra engine a Hemi because it uses a hemisperical cylinder design. If the Ford guy is telling you P means Posi, then Ford would get sued for using a GM trademarked name for it's own use....therefore P cannot mean Posi if you understand what I am trying to get at.

 

[Mike85000]

Gotta hate it when someone thinks they know something and won't listen to a bunch of other people telling them they're wrong.

If your car is 86 + the 8.8 will have the traction-lock.

Ford denoted the T-lok on tags with an "L" as mentioned before.

Maybe you should pop your diff cover, if your car is an original 5.0L car with the original equipped 8.8 you will find the clutch packs which are probably toast if you haven't rebuilt them since you've had the car.

My car acted like a open diff car until i replaced the clutch packs, i stacked the discs and now it chirps around tight corners when i'ts dry.

 

[Darrin]

I never said my rear was not performing properly nor am I trying to say I know everything. Apparently this is something none of us have the answer for. What the "P" on the tag notates. I was only going with what the Ford guy said. The "P" was a designation for a locker rear that made the rear tires spin like it was a posi. He probably said it like we say I'll take a Coke in a restraunt when you order a soda. Even though they sell Pepsi or Rc cola. This guy bought the 1986 mustang gt brand new from Kelly Ford in Town. He is the only owner ans has never done anything but maintain it. He said the rear tires have always chirped when he took a tight turn. The tag has a "P" designation and acts like it has a locker in the rear. The car is a rust bucket and he's parting it out. I never was looking for an argument just a little education but, it's hard when it's conflicting. I should just buy it, open it up and find out.

 

[NKau]

I never said my rear was not performing properly nor am I trying to say I know everything. Apparently this is something none of us have the answer for. What the "P" on the tag notates. I was only going with what the Ford guy said. The "P" was a designation for a locker rear that made the rear tires spin like it was a posi. He probably said it like we say I'll take a Coke in a restraunt when you order a soda. Even though they sell Pepsi or Rc cola. This guy bought the 1986 mustang gt brand new from Kelly Ford in Town. He is the only owner ans has never done anything but maintain it. He said the rear tires have always chirped when he took a tight turn. The tag has a "P" designation and acts like it has a locker in the rear. The car is a rust bucket and he's parting it out. I never was looking for an argument just a little education but, it's hard when it's conflicting. I should just buy it, open it up and find out.

Regardless of what the tag says, I think you are the one who is missing the point here........... If your car is an original 5.0 (should have an 'E' as the eighth digit in the VIN) you already have the SAME EXACT REAREND IN YOUR CAR, thereby making it pointless to go out and buy the SAME EXACT REAREND THAT YOU ALREADY HAVE IN YOUR CAR out of someone else's '86. Does this make sense?

 

[Darrin]

Look guys....I accept what you are saying...ok? I can't find a damn thing on the internet that says otherwise. I just wish I could find out why it has the "P". Like you guys have never been trying to find something out and all the frustration never got to you and you act crazy with kicking the family cat because you feel so alone in your quest. (where is that damn cat)! It's like trying to explain a sound only you seem to be able to hear. That plus the Ford guy is pissing me off with the "posi" term now. Most of my frustration was I just didn't think I was explaining it right. CAN YOU GUYS FORGIVE ME?

 

[NKau]

I just wish I could find out why it has the "P".

Might be a good one for Unsolved Mysteries

CAN YOU GUYS FORGIVE ME?

This time...........

 

[Mustang5L5]

Look guys....I accept what you are saying...ok? I can't find a damn thing on the internet that says otherwise. I just wish I could find out why it has the "P". Like you guys have never been trying to find something out and all the frustration never got to you and you act crazy with kicking the family cat because you feel so alone in your quest. (where is that damn cat)! It's like trying to explain a sound only you seem to be able to hear. That plus the Ford guy is pissing me off with the "posi" term now. Most of my frustration was I just didn't think I was explaining it right. CAN YOU GUYS FORGIVE ME?

Go to a different ford guy because that one is 100% wrong.


I can't find any info on a 3P08 rear end at all. Sure it's not an O?

 

[93 LX]

L = Trak-loc
P= PEGLEG

: and the 08 is a Zero not "O"