Is this a good Posi?

[BillyGman]

I just found this in a magazine. It sounds like the best of both worlds.....

having the durability of a Locker-rear w/the smoothness and quiet operation of a Limited slip......does anyone have experience w/this, or know anyone who is running one? What do U guys think?

[Zack]

i believe Lidio is running this unit and I will be using this piece if mine should ever fail.
Ive heard nothing but good things.
If mine should ever go, I will step up to the 31 spline limo axles in conjunction with this.

[BillyGman]

i believe Lidio is running this unit and I will be using this piece if mine should ever fail.
Ive heard nothing but good things.
If mine should ever go, I will step up to the 31 spline limo axles in conjunction with this.But I thought that Lidio is using the Eaton posi which has clutches? I haven't had any problems yet w/the stock unit on my car either. But I'm just trying to plan ahead like you are incase the limited slip clutches ever do burnout. So far I haven't found much info on items. Their website isn't up and running yet. I've never heard of this product before, so I'm assuming that it's fairly new. But I really like idea of a differential which doesn't have any clutches to burn up, and is also applicable for street driving. I'll write to Lidio to find out if he's familiar w/this.

[Krytin]

If you go to the website www.tractech.com, it looks like they bought out the old Detroit Locker design and added a few. The original was as bullet proof as they come short of a solid spool! You could hear it unlock and lock up again when driving around corners (modern sound proofing might help).

[BillyGman]

yeah, I just heard from Lidio. It's just as i thought....he does have the Eaton posi, and he said to stay away from this one that I've asked about since it makes a lot of noise and wouldn't be desireable for a street car. He highly recommends the Eaton posi. thanks for everyone's replies on this.

[Bowtie]

It's unanimous over on the GM B-body side that Eaton is the way to go for street and strip use. The stock Auburn posi that the ImpalaSS came with is OK for your typical cruiser person, but put it through a few burnouts with slicks and it quickly turns to toast. The Auburn Pro is not much better and, just like the stocker, is non-rebuildable. When the Eaton does wear out, you just rebuild it with new clutches. The Eaton is available with 400 lb and 800 lb clutches. With the exception of 1 or 2 guys, everyone is running the 400 lb and is happy. I've heard the 800 lb acts almost like a spool. I've replaced my stock Auburn with an Eaton 400 lb unit since my 1 legged outing at Marauderville II. I've made 5 passes with it on a test n tune night (not famous for great track prep) and it hooked up perfectly. :up:

Another excellent diff is the Torsen. It uses extra planetary gearsets to bias the torque to the wheel with the most traction - no clutches to wear out. The autocross and roadrace guys love them. The Torsen is not acknowledged to be quite as strong for dragracing as the Eaton is, but there are Torsens surviving behind strokers with weekly dragstrip use for a couple of years without problems. The only one I know of that fragged was behind a T56 (six-speed) Impala launching on slicks.

[BillyGman]

thanks for the info Pat.

[metroplex]

It just so happens that I have the same unit in my 2000 Crown Vic that has seen drag racing, mud driving, ice, snow, sleet, everything except pure off-roading and sand.

You cannot tell the difference between this and the stock open differential in terms of sound. The only way you can hear it make grinding noises is during the first mile where it needs to "Break-in". If you still hear noises for 250-300 miles, then the person that did the install did not do it correctly (most likely backlash was not re-checked and adjusted) but it will still function properly for thousands of miles to come.

I installed it last January (ironically I was in NJ and ordered parts from DTS located on 12 mile and Groesbeck and now I live and work near Warren) and have since logged about 8000 miles of mixed highway/local/drag racing miles.

It is OEM/Lincoln quiet in my Vic. It is a Torsen differential and not a Detroit Locker or a clutch based limited slip. Read up on Torsens and how TORque SENsing differentials operate (howstuffworks.com has a good article) first before asking more questions (just in case you do have more questions)

The basics of the TrueTrac:

Do Not use it if you plan to race with drag radials/slicks and have lots of torque (one example is a supercharged 03 Cobra with drag slicks). The driveline shock from the sticky tires and the monster torque will grenade the unit. It was NEVER intended for such applications. The Military's AM General HMMWV uses Torsen differentials in the front and rear for maximum traction on bad terrain - and the TrueTracs are known to handle 31" or taller profile off-road tires where the Zextel (or whatever company owns Torsen now) Torsen will easily break.

So what is the TrueTrac good for? N/A or supercharged cars running below 450 ft-lb of torque with street tires (or summer tires) and possibly drag radials if you're not making a lot of torque. It's a great street LSD and the only reason your clutch posi's handle that amount of torque and shock is because you wear out the clutch packs. Eventually the clutches wear out and you need a rebuild. A Detroit Locker is probably better suited for a pure drag racer.

I've driven Panthers with a Traction-Lok and a TrueTrac and can say the TrueTrac offers the best control since it works as an open diff until you apply enough torque to cause traction loss (but you still can do 2 wheel burnouts).

The TrueTrac is only about $40-$50 more than a brand new Traction-Lok unit (which Marauder owners should already have) in case you want to retrofit another vehicle.

In your cases, I would not bother with modifying the rear differential until the clutches wear out. I would then rebuild it with the F-150 spring or just go with an Eaton or Auburn or Detroit Locker if its a summer car.

My Vic came with a POS Open differential and it wasn't worth 2 *****s in the snow.

Those are my 2 cents, not yours. :surprise:

[BillyGman]

Thankyou for that info. I will keep all of these things in mind if the stock Trac-Lok unit in my Marauder ever does bite the dust.

[metroplex]

After reading your sig, it sounds like the Detroit Locker is something you should look into. Especially with drag radials or even slicks at the track, your Marauder would absolutely bite the ground and you wouldn't have to worry about anything breaking... except for the axles, rear suspension, driveshaft, and transmission. :D :lol:

[Ram Air 9C1]

TrueTrac is almost identical to the Torsen T2. A few Torsens failed in Impalas with a 1.6x or lower 60' time. Looking at the mods in your signature, I would recommend an Eaton LSD with 800 lbs springs or a Detroit locker.

[BillyGman]

Thanks again guys for all your suggestions, because they are valuable ones at that. The stock rear end is fine so far, and on the track my car hooks great w/these P305 Nitto drag radials. Infact my car hooks so good, that I really cannot see gaining any more than one tenth of a second reduction in my ET even if I went w/the slicks. I've heard of some guys w/Superchargers have blown the stock Ford "Trac-Lok" posi units at the dragstrip. So that's the only reason why I'm looking into all of this just incase that happenms to my car.


This car is my daily driver, so I would NOT put a Detroit Locker in it since it would then be very noisy around the turns on the street. But what I have thought about is going w/the "Powertrax" "NO-SLIP" locker rear unit that Richmond gear sells. A few people have told me that the Powertrax Locker is noisy around turns, but on the Richmond gear website, they claim that only their original Powertrax units are noisy, and that their newer "NO-SLIP" Powertrax Locker is smooth and quiet even around turns during street driving.

So I'm getting conflicting stories on that, however,if I were to go w/any of the Locker rears, then it would probably be the Powertrax "NO-SLIP" one. I guess it would either be that, or the Eaton Posi unit like someof you have suggested.

[metroplex]

The Powertraxx garbage will easily grenade in your application and yes they can be noisy.

The TrueTrac is a stronger version of the Torsen T2. The T2 will fail when using tires taller than 31" on off-road vehicles whereas the TrueTrac will take the abuse (from what I've read).

I would not recommend the Powertraxx, TrueTrac, or the Torsen T2 in this Marauder application though.

Go with a stronger clutch posi or upgrade your Traction-Lok (uses 1 or 2 more clutch discs??? and the F-150 spring which makes for more positive axle lockup).

BTW Toyoda now makes the Torsens - it used to be Gleason then Zexel.

[SergntMac]

The stock Auburn posi that the ImpalaSS came with is OK for your typical cruiser person, but put it through a few burnouts with slicks and it quickly turns to toast. The Auburn Pro is not much better and, just like the stocker, is non-rebuildable.
I didn't know that GM outsourced their Posi-Tractions stuff...Indeed.

Thanks for your input, Bowtie, and I respect your experience with the Auburn. However, that experience is the exact opposite of mine, with the Marauder's OEM Traction-Loc, and it's chosen replacement, from Auburn.

Back in June of '03, I blew out my rear end so bad, I presumed that there was something else wrong, like maybe a bad install. But, I've never found any support for that, and today, I still cannot say I'm sure what went south, except maybe the Richmond gears mixing with 455 RWHP...

Nonetheless, I came to replace everything back there except the OEM housing, I bought "the whole nine yards." I have the X-rated pics of the carnage, e-mail me at SergntMac@aol.com for a zip file. One of the ring bolts damn near punctured the OEM cover...Really!

When ordering rebuild parts from Ford Racing, I decided to replace my Traction-Lok with the Auburn diff mostly because an Auburn is not rebuildable. You cite that as distracting, I think's more a benefit. If some half-wit's "professional experience" is what got me benched, I'm not about to go through all this rebuild nonsense again another time down the road just because some other half-wit "professional" told me he knows rear ends. What's a plus about an Auburn, is that it's not rebuildable. Not by me or any of my half-witt buds anyway.

http://www.auburngear.com/aftermarket/drex

As y'all can see, I can send a blown Auburn back to Auburn for a full rebuild by a real professional, and do so at a fixed rate for that service. Yes, the car may be down a few days while the parts are intransit, but that's life with a race car and I can live with that. The way some of my half-wits show up for work, the car would be down that long anyway.

My experience with the OEM Traction-Lok has not been good. My experience with it's Auburn replacement is about a year old now, and everyday (weather permitting) I'm doing something very wrong, and doing that very hard, with my MM and it's Auburn Diff.

In order to agree with you, Bow, I must presume that 455 RWHP should be able to find the weak points you speak of with an Auburn Diff, and I have not. Not yet, anyway.

IMHO, the Auburn is on par with the Eaton, maybe better because of its retail price point and DREX program...IMHO.

[metroplex]

If you know what you're doing, a rebuild isn't hard.

You had to pull out the old differential to ship it back to Auburn, right? Then what's stopping you from tearing apart an Eaton or Traction-Lok on a bench and sitting down with a six-pack to work on a weekend project? :popcorn:

I think of that as a nice way to relax!!

[Bowtie]

SergntMac, I doubt that you will break the Auburn. By "turning to toast", I didn't mean it would grenade. The friction surfaces on the cones simply lose their bite and you end up with effectively an open dif. If you rarely go to the track, doing burnouts to heat the tires, then you may never have a problem with it. But it takes only a few times with slicks, with one of them grabbing instead of spinning during the burnout, and the unit is done. The "friction" surfaces in a standard Auburn (not sure about the Auburn Pro) are metal-to-metal and won't tolerate near the amount of slippage as the clutch material in an Eaton will before giving up the ghost.
For strictly street use, the Auburn will probably last a good while, regardless of hp. Even with good street tires, the abuse you can inflict upon the posi is limited.

Pat

[BillyGman]

hey guys, I really like this thread!!! Some good stuff in here being shared by everyone I think. And thanks for the warning about the Powertrax MET. I didn't know that they are garbage. That's good to know my friend. I appreciate it.

[Ram Air 9C1]

Auburn differential are not compatible with burnouts. If you don't believe me, just an Auburn representative. As it was said above, they don't blow up but rather start acting like an open differential. It's not a good choice for a street/strip car. About 90% of Impala/Caprice owners replace the stock Auburn with an Eaton differential during a gear swap.

[metroplex]

Bill: I did research on the Powertraxx stuff prior to getting the TrueTrac and I found that the off-roaders got decent results but the drag racers kept grenading them.

Overall, I think we'd get similar results using either a TrueTrac or Powertraxx but the Powertraxx is more expensive and their "Zytanium" construction does not impress me a whole lot. I went with the TrueTrac because of the price, performance (in its intended application), and reputation for traction/reliability in the HMMWV (same principle/design, different manufacturer).

Your application is different because you're applying a LOT more torque and driveline shock to the rear differential and a clutch LSD would make a lot more sense as it provides more positive axle lockup and will transfer the abuse into the wearing of the clutches rather than grenading the whole unit.

I think this is more of what I said earlier, but I thought I'd reiterate this in case this comes up in someone's search. :popcorn:

It sounds like an Eaton might be your solution! :uzi:

[David Morton]

Another excellent diff is the Torsen. It uses extra planetary gearsets to bias the torque to the wheel with the most traction - no clutches to wear out. The autocross and roadrace guys love them. The Torsen is not acknowledged to be quite as strong for dragracing as the Eaton is, but there are Torsens surviving behind strokers with weekly dragstrip use for a couple of years without problems. The only one I know of that fragged was behind a T56 (six-speed) Impala launching on slicks.Went to the Torsen site and it says Ford went to the Torsen in 2001 for the FX4. I've been a fan of this unit since I read a Popular Mechanics article about it back in the '80s, being used in the Humvee. Seems like if they can make one strong enough for the US Army they must have one good enough for a 4200 lb Marauder.

[metroplex]

Went to the Torsen site and it says Ford went to the Torsen in 2001 for the FX4. I've been a fan of this unit since I read a Popular Mechanics article about it back in the '80s, being used in the Humvee. Seems like if they can make one strong enough for the US Army they must have one good enough for a 4200 lb Marauder.

We're talking 110% different applications.

FX4 and HMMWV are designed to be off-roading/all-terrain vehicles (low speed, high tire profiles, lots of drag). The amount of driveline shock is incomparable to 350-450+ ft-lb of torque coupled with drag slicks or DRs (that do not spin much, therefore all the shock feedback goes back into the differential, then the gears, driveshaft, and tranny).

Granted, we're dealing with auto trannies here but your 12 second 1/4 mile marauder isn't a 0-60 in 20 second HMMWV.

You MAY get away with using a Torsen in a supercharged Marauder w/ an auto tranny using street tires, but I'm just voicing my concerns with the design in conjunction with performance applications.

HMMWVs were never meant for high speed drag racing applications (top speed is about 40-45 mph for the N/A models and 60-70 mph for the turbocharged models).

And if it sounds like I'm dissing the Torsen - I'm not. I have one in my Vic and its great; I just wouldn't trust it on a wild ride like his 12 second Marauder.

[David Morton]

We're talking 110% different applications.

FX4 and HMMWV are designed to be off-roading/all-terrain vehicles (low speed, high tire profiles, lots of drag). The amount of driveline shock is incomparable to 350-450+ ft-lb of torque coupled with drag slicks or DRs (that do not spin much, therefore all the shock feedback goes back into the differential, then the gears, driveshaft, and tranny).

Granted, we're dealing with auto trannies here but your 12 second 1/4 mile marauder isn't a 0-60 in 20 second HMMWV.

You MAY get away with using a Torsen in a supercharged Marauder w/ an auto tranny using street tires, but I'm just voicing my concerns with the design in conjunction with performance applications.

HMMWVs were never meant for high speed drag racing applications (top speed is about 40-45 mph for the N/A models and 60-70 mph for the turbocharged models).

And if it sounds like I'm dissing the Torsen - I'm not. I have one in my Vic and its great; I just wouldn't trust it on a wild ride like his 12 second Marauder.And now the rest of the story. (Sorry if it looks like a 'gotcha'. I just finished doing my homework. I gotta stop popping the the clutch on keyboard before engaging the gear on the Google.)

http://www.torsen.com/products/T-2R.htm

Here I go again. Now to look for the price on the Ford 8.8" unit.

[metroplex]

The T-2R is not the same as the T-2. The main difference is that the T-2R utilizes clutches in conjunction with the helical cut gears for torque biasing. The T2 does not use clutches (T2 is what is used for the HMMWV and off-road vehicles. I have not heard of many T-2Rs being used in racing applications but its only available in 31 spline form for the Ford 8.8) Again, the clutches will take the abuse and will be destroyed well before the unit grenades itself... thus we come back to the original application at hand and a HD clutch posi is the recommended differential.

[BillyGman]

Bill: I did research on the Powertraxx stuff prior to getting the TrueTrac and I found that the off-roaders got decent results but the drag racers kept grenading them.


metro, I'm wondering if the people you've conversed with, or who have written whatever literature you've read on the Powertrax units are getting something mixed up. There are two Powertrax units. One is called the "Lock-Right" unit, and is intended for off-road trucks, while the Powertrax traction system (aka "no-slip") is intended for high performance street/strip use. And their original Powertrax "Lock-right" model that's intended for off-road trucks, is infact the original product. So I'm getting the impression that most people who've had any experience w/the Powertrax product, has had that original one called "Lock-Right".

[metroplex]

It's the same thing basically. the Lock-Right is cheaper and noisier. The Lock-Right/Powertrax NoSlip is just the same as a Detroit EZ Locker.

The folks that had issues with drag racing and a Powertraxx product were using the NoSlip. I've done the research on the NoSlip and I just didn't like it after hearing about the problems on cars, how it doesn't like to unlatch in turns, and how it's very noisy.

Off-roaders say they like the Powertraxx and use them in the front differential and a TrueTrac in the rear differential. Again, off-roading and all terrain vehicles like the HMMWV are designed for a different application (low-speed, low-shock) whereas a 12 second marauder loaded with drag slicks will be a high-speed, extremely high shock application.

[BillyGman]

Okay met. Thanks again for your reply. Sounds like some good 411 ;)

[1 BAD 03 MM]

Just one question, does Auburn make the OEM diff in our MM? I was wondering who Ford outsorced this to. Thanks in advance. :flag:

[metroplex]

It should be Visteon... :drive: