Limited Slip Diff unit (LSD) - need input

[Willie Makeit]

Looking for input. About to pull the trigger either on a Detroit TrueTrac or the Eaton Posi unit.

Tell me your experiences with either/both.

Going in a 3.73 GM truck 12 bolt behind a TH350 hooked to a 5.3 bottom-end LS with an LSA/ZL1 super charger on top. Leaning now towards the Detroit TrueTrac unit only because it does not use clutch packs. Not looking to make track passes with the truck, just a cruiser/sleeper on street tires.

Share your thoughts both good and bad on either or if I should be looking at something else.

Thanks!

[H20cooled]

I installed the Truetrac this summer with no issues at all, runs dead silent and provides great traction. Not sure what else to say than that as I have not had any negative experiences with it.

[clinebarger]

Yukon "Dura Grip" Clutch type posi.....4320 Forged spider gears. Though the Eaton Posi is a good unit also., Posi Clutches last a LONG Time....Easily 100K with heavy abuse with the composite clutch materials we have today.

The TrueTrac is a decent unit, They don't like to be shocked with big power & sticky tires, The little worm gears break/strip.

[GMC-YA68]

I did the Eaton posi. Awesome unit and they are rebuildable.

[Houston Ben]

I installed the trutrack with no problem. Hooks good and you don't know it is in there till you need it.

[BR3W CITY]

I like the posi myself. Eaton builds everything from spaceshuttle components to military hydraulic gear drives. They can build a strong posi for sure.

[homemade87]

The only problem I hear most have with the clutch style is they dont use the proper fluid and additive . It will pop ,grunt ,premature clutch wear and a few other noises if the proper fluid is not used .Some People think they now better than the manufacture about what fluid to run . Use exactly what they say to use and no off brands of the additive either . I have only run clutch style posi in all my rears and have never had a problem and all have been as quiet as a mouse .

The trutracs do not lock 100% (left to right ) like the clutch type do. If off road with one tire in the air this is not desirable . On flat ground snow or ice these work good . Also not recommended for tires over 33"

I still prefer the clutch type for every day and performance driving .

[BR3W CITY]

Originally Posted by homemade87

Some People think they now better than the manufacture about what fluid to run . Use exactly what they say to use and no off brands of the additive either .

Using the proper friction additive is 100% responsible for keeping your LSD alive. I've run the GM Friction mod, the Eaton friction mod, and also tried some of the "no additive needed" high performance gear oils. Truth is, good old Napa/Valvoline gear oil with the GM or Eaton friction mod outperfromed the $15+/qt stuff from the "premium" brands.

[Willie Makeit]

Originally Posted by clinebarger

Yukon "Dura Grip" Clutch type posi.....4320 Forged spider gears. Though the Eaton Posi is a good unit also., Posi Clutches last a LONG Time....Easily 100K with heavy abuse with the composite clutch materials we have today.

The TrueTrac is a decent unit, They don't like to be shocked with big power & sticky tires, The little worm gears break/strip.

I like what I'm reading about the Yukon unit. Thanks for the suggestion!

[Jon01]

Spend the $ and get a true-trac.
I've broken posi's behind 300hp small blocks as such whenever I go through a diff in something it gets upgraded.
My truck has a true-trac, as does my wagon. Truck makes ~650whp, no idea on wagon.
True-trac is also 100% seamless in it's operation and requires no special fluid/additives.

[clinebarger]

Originally Posted by Jon01

Spend the $ and get a true-trac.
I've broken posi's behind 300hp small blocks as such whenever I go through a diff in something it gets upgraded.
My truck has a true-trac, as does my wagon. Truck makes ~650whp, no idea on wagon.
True-trac is also 100% seamless in it's operation and requires no special fluid/additives.

Are we talking about the same thing? Detroit Locker & Detroit TrueTrac are 2 different things, A TrueTrac is near the same price as a Eaton/Yukon, A Detroit locker cost a couple hundred more.

[BR3W CITY]

Originally Posted by Jon01

I've broken posi's behind 300hp small blocks as such whenever I go through a diff in something it gets upgraded.

Broken how?

[Jon01]

Did you read my post?

I have beat the dog piss out of mine and nary an issue. Always turns 2, be it out of the hole or from a 50 roll.
Wagon weighs 4k+, is on mt dr's full time and has 3 pedals. My only concern with it is which gear do I sidestep the clutch in.
Truck will be getting a 30" et drag this spring, I anticipate zero issues other than stock axles being on borrowed time.

I've had clutch posi's in Dana 60's behind big blocks which are stronger than the 12 bolts in our trucks.
There's a reason I spent the $ to upgrade the s60 under the wagon. Hammer a clutch unit good ala 3rd gear attempted burnout with one tire in water or off pavement and you'll be in it replacing clutches..

I've done it. Also broken spider gears and cases themselves due to ejected cross shafts.

OP stated his rig will live on street tires so shocking it is further a non issue, not that it was - plenty of people running them in cars cutting sub 1.4 short times without am issue.

Truetrac and forget about it.

[Jon01]

Originally Posted by BR3W CITY

Broken how?

Broken cases, cross pins spit out, destroyed spider gears. .

[GMC-YA68]

Originally Posted by Jon01

Did you read my post?

I have beat the dog piss out of mine and nary an issue. Always turns 2, be it out of the hole or from a 50 roll.
Wagon weighs 4k+, is on mt dr's full time and has 3 pedals. My only concern with it is which gear do I sidestep the clutch in.
Truck will be getting a 30" et drag this spring, I anticipate zero issues other than stock axles being on borrowed time.

I've had clutch posi's in Dana 60's behind big blocks which are stronger than the 12 bolts in our trucks.
There's a reason I spent the $ to upgrade the s60 under the wagon. Hammer a clutch unit good ala 3rd gear attempted burnout with one tire in water or off pavement and you'll be in it replacing clutches..

I've done it. Also broken spider gears and cases themselves due to ejected cross shafts.

OP stated his rig will live on street tires so shocking it is further a non issue, not that it was - plenty of people running them in cars cutting sub 1.4 short times without am issue.

Truetrac and forget about it.

This post confirms why I will never run a lunchbox locker.

[Willie Makeit]

Originally Posted by Jon01

Spend the $ and get a true-trac.
I've broken posi's behind 300hp small blocks as such whenever I go through a diff in something it gets upgraded.
My truck has a true-trac, as does my wagon. Truck makes ~650whp, no idea on wagon.
True-trac is also 100% seamless in it's operation and requires no special fluid/additives.

Thanks for your input Jon. After researching this subject for several days, the TrueTrac keeps coming back to the top of my list too.

[Willie Makeit]

Just a reminder guys: PLEASE BE SAFE!

cleaning the rear end housing tonight and it fell off the jack stands. the pinion snout landed on my finger resulting in the loss of the end of my index finger back to the first knuckle on my left hand.

Hating life right now but thankful for good meds.

[LockDoc]

Originally Posted by Willie Makeit

Just a reminder guys: PLEASE BE SAFE!

cleaning the rear end housing tonight and it fell off the jack stands. the pinion snout landed on my finger resulting in the loss of the end of my index finger back to the first knuckle on my left hand.

Hating life right now but thankful for good meds.

Wow! sorry to hear that. That's gotta hurt....Hope you get healed up quick so you can get back to work on your truck though.

LockDoc