Limited slip or locker??

Not a tuning issue.
Thread moved.

Id say the limited slip is your problem, when both rear tires are spinning at the same time its very easy to get the car sideways, and depending on your rear gear ratio even light acceleration can cause the tires to spin and get the car loose in the rain.

my car had the factory trac-lok LSD, which was worn out when i got the car and it would not get sideways very easily. I had an eaton LSD unit installed about a year after i got the car, along with a switch to a 3.73 rear gear from a 2.73. the change was awesome for driving on dry pavement, but in the rain it got scary.
the car went around on me at a corner near my house about a week after the swap and soon after that the car got real loose while passing someone in the rain on a trip to seattle, i rarely drive the car in the rain now and am very careful when i do.

the only thing i would do if i had to drive in the rain alot would be to get some quality tires that were made for rain or all seaon weather, and keep the engine rpm as low as possible while driving

There are no two different categories of limited-slip devices like you are implying. A full, manually controlled, locker rear end (like what is seen in 4-wheel drive vehicles) is extremely uncommon in street/strip applications, and honestly, not really practical unless you are trying to climb out of a swamp and over a dead tree trunk in your Mustang (note my sarcasm). The stock Mustang GT unit is what Ford calls the "Traction Lok", and is simply a multi-clutch disk LSD (limited slip differential). Like said above, the fact that you have a LSD in your car is what makes both wheels spin, and the fact that the 302 is pretty torquey in a small vehicle is what makes it easy to get sideways.

Here is a breakdown of common types of rear ends in street cars:

Open: No clutches, axles are free to spin at any speed in relation to the other. Good for granny driving to the grocery store in her Buick.
LSD: Some amount or type of clutches (though some fancy designs don't have clutches, IIRC) that work to keep the axles spinning at the same or close to the same speeds. These are ideal for accelerating traction, and the Traction Lok that came stock in the 5.0 Mustang is a type of LSD. These are also good for road racing, as their flexibility allows for solid traction in turns without fully locking the axles together.
Spool: A spool is a solid, clutchless, mechanical linkage between the axles in the rear end so that they are always forced to spin at the same rate. Great for drag racing and driving in a straight line, not so great for cornering or trying to navigate a parking lot. They are called "spools" because they kind of look like a thread or rope spool. Typically only used in extreme straight line performance vehicles.

It all comes down to this: it sounds like your LSD is operating properly and the only thing you SHOULD do is buy better all-weather tires and learn to drive more carefully if you intend to drive it in the rain. Your only other option would be to swap in an open differential (which has zero axle locking ability), which is counterproductive from a performance standpoint, and I would NOT recommend it.

Tires have a lot to do with this too. MY supercharged Cobra actually gets good traction in the rain with Nittos. Once I take off and get moving, I can hit the gas mid way and it won't spin. Obviously if I mash it down to the floor it will, but it will acclerate pretty damn good without spinning. HOWEVER, these Nitto's have tread on them....I had bald ones once....OMG....I thought I was on ice. Very very dangerous in the rain.

BFG KDWS are also good in the rain. If you have crappy old, bald tires, that's a nother contritution to your problem.

I don't think you're understanding me here. If your Mustang came with a V8, it came with the Traction Lok limited slip differential. If you are getting "one wheel peel", its only because the Traction Lok needs rebuilt.

You need this kit to rebuild it:
86-08 CLUTCH KIT, TRACTION LOCK, 8.8" MUSTANG

This "posi trac" you keep referring to is actually a nickname for Chevrolet's "Positraction" LSD.

Read this article:

Limited slip differential - Wikipedia, the free encyclopedia

NikwoaC said:

I don't think you're understanding me here. If your Mustang came with a V8, it came with the Traction Lok limited slip differential. If you are getting "one wheel peel", its only because the Traction Lok needs rebuilt.

You need this kit to rebuild it:
86-08 CLUTCH KIT, TRACTION LOCK, 8.8" MUSTANG

This "posi trac" you keep referring to is actually a nickname for Chevrolet's "Positraction" LSD.

Read this article:

Limited slip differential - Wikipedia, the free encyclopedia

Click to expand...

X2.

All V8 stangers came with a posi/traction lock whatever you want to call it. BOTH rear wheels should spin. As Nikowac said, you need a rebuild kit for the diff.

!white89lx! said:

Im pretty sure the 89 lx did not come with an lsd aka posi trac as an option and if it did come as an option my car doesnt have it.
The burn outs are typical of the open differential because of the pesky one rear tire mark left on the pavement.
im deffinately leaning more towards the lsd because i like turning without dragging one tire in the opposite direction

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I was assuming you had a 5.0 since you posted in 5.0 tech. I have the same year/trim mustang as you with a 5.0 and it had the LSD from the factory.

Im just guessing that you had the same problem i did, the trac-lok was worn when i got the car and on dry pavement it always did the famous "one tire fire"
In the rain though i could get both tires to spin so i always figured that the trac-lok was just too worn to apply power to both tires on dry pavement but still had enough left to apply power to both tires in the rain

After installing a new LSD it became way easier to get the car sideways even accidentally in the rain compared my old worn out trac-lok which usually acted like an open diff.

Don't go with a Detroit Locker if you do alot of street driving.
I have one in my car. It makes a racket unloading and reloading on corners, but you don't get the wheel hop that you would with a spool. I don't really use it on the street that much anyways.
I put it in only because I toasted my clutches on my eaton posi in just 2-years, all from 4200 rpm launches shocking the posi with slicks when I drag race.
I just didn't want to have to rebuild the posi all the time.
Like everyone else said: good tires and conservative driving habits in wet weather will help a lot.
Good Luck!

!white89lx! said:

Im pretty sure the 89 lx did not come with an lsd aka posi trac as an option and if it did come as an option my car doesnt have it.

Click to expand...

The differences between the LX and GT are purely comfort and cosmetic. Performance wise the LX has a slight edge since it is a lighter car. The drivetrains were identical as was the suspension.