I was doing some searching on this and other forums about if one should go for a Helical LSD, e.g. Torsen, Quaife, Truetrac; or if one should choose a Clutch Based LSD, e.g. Trac-lok, Auburn, Eaton.

Various things that have been brought up against Clutch Type LSDs are that they engage harder and more roughly than a Helical type, and that a rebuild of a Clutch Type is expensive.

I guess my questions are, do clutch type LSDs engage disagreeably hard for around town driving? Would shorter gears, like 3.27-3.73 make the engagement more disagreeable? How much does an LSD rebuild cost? And is there any reason I shouldn't just go for a Ford Trac-lok since it seems to be the least expensive and it's from ford and meant for these? Btw we're talking low power application here. Right now my car is stock and eventual power goals won't exceed 300 or 350WHP.

Thanks for your answers

The only time you're going to get chatter from a Trac-Lok is if the clutches are set up too tight, or if it's worn all the way out. They're meant for street use, which means quiet and smooth.

Torsen, etc is really meant for applications where there's a good bit of differential speed that would burn up a clutch-type locker. Center diff in AWD, high-speed track use, etc. It's overkill in a Panther.

I ran Ford's Trac lok diff in all of my cars and it did great in every day dituation but it is a marginal piece of "performance".
I got a detroit truetrac (gear type ) for my 04 but I havent even ran the car yet . I am making lots of power , doing drag racing and planning to road race the car so I needed a stronger unit capable of locking up pretty hard off the line but also being able to unlock in sharp turn when racing .

The initial cost is higer but when you factor in the cost of replacing the clutch pack and labor there is not a whole difference at the end of the day .
The gear type diff is more transparent for every day use, and if I remember correctly they are standard in newer stangs .

Completely agree.

I should add that thorsen begins to close at moderate powers. I am using Amsoil110. At 80W90, the closure will occur even earlier. But the closure happens quite neatly. And you feel it and you can control it.
Finally, I have recent experience of driving in the wet snow on summer tires. In general, I do not regret the money spent.

Yeah, I guess I want to know how often/how much a Trac-lok rebuild is? I've heard 30k-100k milage, and how much it will run. I know it's about $150-$200 for the parts.

Also, would you say that a Torsen style is worth it when my power goal is 300WHP or less?

A rebuilt clutch pack goes for 130$ plus oil and labor .
clutch pack wears like anything else put depending how you drive the car it can be within a season or many years .

The hp rating has nothing to do with the choice of diff but how you want to use the car .

Gear type diff would be overkill on a daily driver but could find it's use on a daily driver in canada where snow is an issue .
You want to do track session it is for you .

They still use the clutch Trac-Lock in the '15-up 'Stangs, even the base V6 models - I've checked. I think the Torsen is still an option on the higher-end models, though.
Too bad we can't use them in our cars; they have 34 spline axle shafts.



One important thing to remember about Torsen differentials is that they require some resistance on the tires to be able to lock.
In a situation where one tire has none or almost no resistance (EX: One tire is in the air, or on a patch of ice), it will behave like an open differential and just spin that wheel until the cows come home.

One quick fix that I've heard about (but never had to try): put your emergency brake on for a few clicks, and that SHOULD give the loose wheel enough resistance to make the differential lock up.

For the record, I've got a Trac-Lock in my Grand Marquis, and a Torsen in my '89 Firebird.
I think the Torsen is a superior design, but just go with what you can get the best deal on.

There are versions with preload. Unfortunately, this is an expensive pleasure.

thanks for the clarification

Yeah, I guess what I'm really trying to figure is for a workload that is almost all California streets, but might include track use, snow, and towing, would the characteristics of a Trac-lok or a True-Trac be better, or rather is a True-Trac better enough to be worth the cost increase? I really don't figure that I'll be beating on either hard enough that if I chose a clutch based I'd wear through them any time soon.

Okay, I just read your signature list, and if you're driving an '09 CVPI, you should already have a Trac-Loc clutch differential.

To test this, jack one wheel off the ground, and try to spin it. Grab the tire at 3-O-clock and 9-O-clock, and try to turn it as hard as you can.
If it won't turn, the LSD is still good.
If it's really hard to turn, but it does turn, it's still good.
If it's kinda hard to turn at first, but then starts turning, it's probably still good.

Ultimate test: do a burnout, and see if the tracks are the same length.
I've seen some cars/ trucks with seemingly worn-out clutch differentials still lock the rear wheels when slippage happened.

The axle code in the door jamb says 3.27 open, and I've given it enough gas on dirt where it breaks loose, and then when I came forward onto the pavement I left one tire mark. I also gave it a good stab on gravel one time and it's definitely only the right wheel that spins.

I prefer torque biasing units over clutch and cone type, and have a Torsen T-2 on mine.

The OE style units are rebuildable, and you should be able to get 100,000 miles out of it. Some folks also switch the S springs to increase pre-load.

speaking of cones type, on top of my head I dont remember seeing that type of diff standard on vehicules .

Cone type (Auburn) was a standard option in the General Motors world at some point like mid 80's and on.