Powertrax (or like kind) vs Posi? READ FIRST

[tougeagle]

It's coming up on time for me to rebuild my rear end. I discovered that's where all of my drivetrain lockup is happening. Lately, I've been making some heavy dough and I'm going to sock some of it back for the rebuild. Problem is this: a fully loaded posi carrier, and a powertrax (or similar) automatic locker are the same price, and I'm not exactly sure which one I want to get....

Keep in mind!: My rig is NOT going to be a trail rig, it's my daily driver and I prefer it to be fast and handle well over being tall and capable, but at the same time any extra traction I can add for the winter is a huge plus.

Problem is, I've got no experience with automatic lockers, and I don't know if/how it would change my car's road manners. For instance, if taking a tight switchback turn on a paved road, would the rear end hop or chirp with an automatic one? I know that a posi would have better road manners, but also would require some additional specialized fluids added in with the usual 80-90....

So, I would love some advice, but keep in mind I am not lifting mine nor does it see heavy amounts of trail and that won't change...

[eaglefreek]

I assume you mean a clutch type LSD (limited slip differential) when referring to "posi". I don't have any experience with auto lockers but have a factory Trac-LoK in my Chrysler 8.25 rear and seems to work quite well on the road. Chirps a little when turning a tight corner.

[tougeagle]

It's clutch type LSD... I'd honestly rather have a locker, but if it causes any chirping that would take away from what I want for it..

[eaglefreek]

It's clutch type LSD... I'd honestly rather have a locker, but if it causes any chirping that would take away from what I want for it..

Trak-Lok is a clutch type which are the ones that typically let the tires chirp when turn corners. The auto lockers supposedly act like an open differential when turning corners and not hard on the throttle.

[tougeagle]

It's clutch type LSD... I'd honestly rather have a locker, but if it causes any chirping that would take away from what I want for it..

Trak-Lok is a clutch type which are the ones that typically let the tires chirp when turn corners. The auto lockers supposedly act like an open differential when turning corners and not hard on the throttle.

that would be ideal, much easier to install. I'm still going to rebuild the diff though I wouldn't be required to with this, should be easier to reset ring and pinion

[cj71983]

your wagon is so heavy that with a lock right it wont chirp the tires trust me it will unlock  i have a aussie locker in my 8.25  under my wagon and love it and its my DD

[Mechanic]

To be honest, the only reason you should have something like an Aussie locker or a detroit locker (an auto locker that disengages when going around corners but is solid when going strait) would be if you did off road. An LSD is perfect for pavement use as it gets equal power going to both rear wheels all the time without the ratchet noise of a auto locker and despite what everyone says, smoother. Although, they could have made leaps and bounds in the auto lockers since i last drove a truck with one. If your going to be sticking to the streets then get a limited slip.

[tougeagle]

I'll be sticking to the streets but am upgrading to put emphasis on snow and especially ice traction

[Mechanic]

Neither will give you any better traction over the other. And to be honest. From a man that lives in Canada and has to deal with snow and ice. And from someone that has driven vehicles with both open rear diffs and limited slip rear diffs. I would stick to the open. For the simple reason that it's less likely to kill you when your not looking. If your at a set of lights in 2X4 turning right in an open diff, dosen't look slick but it is, you give her a little gas around the corner and the inner wheel spins. You just ease off the gas and flick it into 4X4. Yu come up to the same corner in the same manner with a vehicle with limited slip everything is going to go fine until you give it a little gas around the corner. Now your sideways.

Now, i drove a winter with limited slip and was fine, I'm also 18 so the sideways action is a bonus for me. It's that it catches you when you aren't expectcting it. If you drive a limited slip car in 2wd at any time during the winter, your car is plotting to kill you, it just is. Lol

Sorry for the long, wishy washy post. And I still don't think I answered your question.

[68AMXGOPAC]

I like the limited slip in my AMX, but it is true, a little gas on a corner and your sideways.Let alone doing a burnout,LOL . No matter what mine won't stay straight !!, and by second n just hitting third it starts to strighten out and catch up with itself.

[Whuntmore]

I don't know alot about rear axles, but I can tell you from experience, that limited slip rear ends rock in the snow.  I've had two cars with LSD, and my old Bronco 2 had a limited slip rear.  That little truck was awesome in the snow, off-road, and off-road in the snow.

Now the motor was one of those old 2.8 V6, so not allot of power there, but she was great for traction.  I ran it with 235/75/R15's.  I never got her stuck, and I even pulled out a Toyota 1/4 ton pickup (ya know, those '80's black, lifted ones) outta a snow bank during a brutal snow storm in Halifax in '91.  We had gotten over 2 feet (yup 24 inches or more) on one weekend, (actually, over the course of a week, we had gotten 115 cms of snow - 30 cms is a foot - So that's almost 4 feet of snow - I remember because I recorded it in my hiking logbook. )  

He had all season tires on it, and he got it jammed into almost a 3' bank on the shoulder of the road.  I chained up, and yanked him out no problem.  No studs, just winter tires.   I had traction, cornering, and handling in that sucker.  

Now, I can't tell you what they are like for launching at high speed or drifting, but for normal driving, they are really great in the snow.

I want one for my eagle...

[maximus7001]

When I ordered my 97 safari AWD van I went with the G-80 LSD in the rear diff, here is why:

 The first AWD van that I test drove for a weekend had the G-80 LSD and the second one a few weeks later had an open diff. Both of these vans had the same tires. These were extended weekend test drives and were taken on skiing trips.

The difference was like night and day. Both vans were driven the same routes and the open diff one had way less traction when it was needed the most.

After driving the 85 wagon for most of this winter with newer tires that used to be on the 97 safari I have decided that it needs a LSD as well, preferably before winter.

[Sunny]

Now the motor was one of those old 2.8 V6, so not allot of power there, but she was great for traction.  I ran it with 235/75/R15's.  I never got her stuck, and I even pulled out a Toyota 1/4 ton pickup (ya know, those '80's black, lifted ones) outta a snow bank during a brutal snow storm in Halifax in '91.  We had gotten over 2 feet (yup 48 inches or more) on one weekend, (actually, over the course of a week, we had gotten 115 cms of snow - 30 cms is a foot - So that's almost 4 feet of snow - I remember because I recorded it in my hiking logbook. )  

Fulltime Positraction will chirp when you turn, aswell as wear one your tires a lot faster. [Look at the tires on a car and you can tell instantly if it's got a fulltime locker or not]. I've got an Eaton LSD in my car and it's great. Instant posi when I hit the gas, but unlocks around corners [unless I'm hard on the gas]. My truck has one too, but it's a bit less responsive than my Eaton.. which is literally instantly.. Punch the gas, and both black lines are the same length. In my truck it takes like half a foot for it to kick on.

Also. I don't think Toyota made 1/4 ton pickups in the 80s. If you are refering to the Helux/Pickup it was a compact truck.. A buddy of mine has one, they're actually surprisingly capable offroad.. garbage power, but the thing's got like 400K on it and it still runs like brand new..

Also.. 2 feet = 24 inches. 

[tougeagle]

Looks like it's gonna be hard to make a decision...

As a reminder, my car is fulltime awd, no switch needed, thanks to the 249 swap.

I'm not worried about going sideways as much under power since it is awd, though it would be enough to make a difference and right now it's stable as it gets under WOT at 4k rpm off apex, it CLINGS to the pavement even with decreasing radius corners..... I want good traction on the street when I punch it apexing out of a tight corner on dry pavement. I want to be able to take off from a light or hill on tightly packed snow, or ice, and have instant grab... I hope wanting these two things isn't asking too much from either system.... if it is, maybe I'll save my money. Decisions, decisions... I'm getting studded snows for this coming winter either way, though that's more for the stop factor than the go factor...

[shaggimo]

Well if you want instant grab, go locker, a LSD is just that, "limited" it's better than open but not much. The factory unit that is in my jeep (Dana 44 LSD), works ok at best, I still catch it only spinning one wheel on occasion, a properly functioning locker is much more predictable than a limited slip. I have figured out how to trick the LSD into working when it doesn't want to, but a locker won't be nearly as finicky, hit the gas, and it's there waiting for you, lol.