I'm just curious, I have 3.55 gears installed from Ford, and that is supposed to be with a Limited Slip Differential. Is that the same or similar to what used to be called Posi-traction? As in, both wheels drive equally? Or is there still one drive wheel that is more primary than the other like on my ancient Ford Ranger which always seem to use the right wheel as the drive wheel.

Can any of you knowledgeable folks help me understand this or point me to a good place to read more about it?

 

The limited slip is very similar to the old Posi-Trac. It uses a set of clutches to help provide traction to both wheels. It is not a locking type unit, and won't totally lock both wheels. If one wheel starts spinning though, it will provide a considerable amount of power to the other non-spinning wheel.

 

I thought I'd read about 1way and 2way differentials, what kind is ours? Also when you take off, is the power really being planted equally between the two wheels? As I recall, most of the burnouts I've seen GTs making were two black tracks and not one. Is that a factory setup, or the result of rear end changes?

 

We have a limited slip (LSD), which acts like a posi but will allow one tire to spin faster than the other in some circumstance, making it better in cornering than a posi.

Edit: there is open differential also, think the V6 has this, it's probably the most common type in passenger cars. If one tire is not getting traction all the power goes to the other wheel. So you can make single line burn outs

 

I don't know what you're talking about 1 way and 2 way diffs...never heard of that term.

When you take off, power is distributed equally between both wheels. If one wheel slips, it can spin faster than the other one...true. The other one will still get some power though, unlike an open diff. which is what the V6's have, and almost every other passenger car out there. In an open diff. when one wheel loses traction, it will sit and spin, and the other wheel will get no power.

This is the way all GT's are set up from the factory, with a Limited Slip rear end...no matter your gear option.

 

So if I understand correctly, then, with the limited slip, power is being distributed relatively evenly between both wheels on take off, but power is given more to the wheel that isn't spinning as fast for better corner traction?

Oh, and never mind the 1way 2way garbage, embarrassingly, I got that from Gran Turismo. lol Hence, since I know nothing about differentials, why started this thread to ask a little bit.

 

Essentially, you have the right idea. It's not a locked rear end where both wheels turn exactly the same speed, but it's also not an open rear end where either wheel can spin freely. The two wheels can spin at different speeds, but there is pressure on the slower moving one to speed up, and vice versa. The clutches inside the rear end try and keep the two wheels spinning the same speed, but don't absolutely limit spin either. This allows you to go around corners and such.

Ever tried going around a corner with a locked differential? I have and it is difficult to say the least.

 

Am I right in thinking the Traction Control off button has no bearing on this functionality but just the fancy braking,timing, fuel cut function to force a slowdown?

 

Correct, the Traction Control has nothing to do with the Limited Slip Diff. If one or both wheels starts spinning, the TC will engage to help stop wheel spin, and it has several different ways of doing this.

1) cut engine power either by pulling timing, or reducing throttle.
2) apply the rear brakes to slow the spinning wheel.

Now it seems to me, that if only one wheel was spinning and the TC was on, it would use the brake on that wheel to keep it from spinning. (keep in mind this is just me thinking out loud and I have no idea if this is actually how it works)

 

FWIW
http://auto.howstuffworks.com/differential4.htm

 

The Infiniti G37 Coupe, the 330 hp competitor to the Mustang, has a viscous coupling limited slip differential, which is a fancy way of saying it uses wet clutches to transfer power between the rear axles.

It gets more complicated when talking about AWD systems. Almost ALL "AWD" systems have an open front differential, except for 3 vehicles that I have found:
Subaru WRX STI
Lancer Evo GSR (Evo X)
Lamborghini Murcielago

At best, some of the "AWD" may have a limited slip rear differential, but almost 90% of the "AWD" vehicles have all open differentials except in the center/transfer case.