Eaton locks both tires together no matter what until you overcome the spring pressure holding the clutch plates. A Tru Trac as I have said before is a purpose built design called torque bias. It shifts power from the tire with the least grip to the one with the most and is aimed directly at road racing. I don't see you road racing your truck, lol. After expericence with both the clutch pack LSD is a better choice imo. Guys just love the tru trac because they look at it as never wearing it out. An Eaton clutch type can easily last 100K miles before rebuild and I never keep anything that long myself, lol. Plus if it does, just put new clutch plates in it and go again.

The Eaton clutch plate is a nice easy to live with simple limited slip and works very well on the street and on the strip.

 

The guy who did my swap, mcclelland performance. An I do some street racing shhh lol

 

Street racing is still in a straight line or somewhere you can run at high speed in a truck and maintain control. Road courses are lots of tight twisty turns ( track dependent) and relies heavily on suspension setup. Very few guys road race pickup trucks, some but not many. I think a good majority have or still do street race, moreso the former for me as I have had my fill of it.

And out of your choices go with 4.10's. Personally especially with an 80E and that size tire I would go 4.30's myself but 4.10 is a lot better than 3.42. Don't fear the gear, lol. And launching in 4HI alleviates most of your traction problems either way. 4.10's will help your mileage, not hurt it. If slow rpm's were all that we would all run 40" tires and use 2.73's lol. I know, thats a bit of exaggeration, but your lack gear reduction in a 4L80e in first make running a lower gear much more pleasant to drive.

 

410's in that truck would be fine esp with a tire as tall as you have..

 

Can I swap the posi without messing with the gears ? I could see how it helped me first, but idk exactly how a rear end is put together.

 

Yes but you still have to set your contact pattern and backlash. You might be able to reuse the stock cast shims and you might not. The worst part with worn gears is if you don't get them back just the way they were, or very very close, they howl. Once gears have miles of use on them they establish a pattern of wear and you need to keep them that way is all I am saying.

If you have never rebuilt a differential before you are best to get someone that has to help you. It's not super hard to do, but just mostly a trained eye and hand helps when setting bearing preload and getting the tooth pattern right. You at a minimum need torque wreches ( dial over click works better for this in my experience) and and a dial indicator. A pinion depth checker is nice too, especially if you are regearing but it's not necessary. I just have never used one I should say, lol.

 

This is a post I made over on the Pacific Performance Engineering truck site

For everyone's info:

Here is an exploded diagram of the Eaton LSD, as you can see there is no mechanism that would allow for a delay of clutch engagement or disengagement. Axle loads simply overcome the frictional forces of the preloaded clutch/steels pack. This is the reason why clutch type LSD's like the Eaton LSD require friction modifier to keep the clutch packs from chattering as the clutch packs slip during while the vehicle turns.
Stock it comes with 400 lb springs in it that press the clutches together, there is also a 200 lb preload spring assembly that is optional. Both the 200lb and 400 lb units use carbon fiber clutches. You can buy the optional 800 lb spring assembly for even more positive torque distribution, but the carbon fiber clutches arent used. Some guys notice tire scub with teh 400 lb units, even more with teh 800 lb preload springs.




The stock G80 (developed by Eaton) has cluch packs that only "apply" when axle speeds differ by 100rpm. A centrifugal assembly causes the cltch packs to disengage at speeds above 30mph. The G80 "GHov Lock" is a locking rear differential as once it "locks" the clutches are not designed to allow slippage.


Here is an exploded diagram of the Auburn LSD, it is also an LSD type that transmits torque to each wheel until axle forces cause the cone/clutches to overcome their preload and allow for axle/wheel differentiation.


Here is an exploded view of the Truetrac, it uses gears to distribute torque across both axles, the wheel with the most traction gets the torque, to a point. As stated if you have a wheel in teh air, it will freewhaeel. You apply the parking/emergency brake which applys drag to the freewheeling tire, and provides torque again. People have very good opinions of the Eaton Trutrac, it has no clutches to slip so its durable and actually biases torque between both axles depending on traction. If coming out of a corner torque is applied to BOTH tires variably, instead of 1 or the other like some others. Since there is no clutches, the possibility of thermnal damage from the traction device itself is minimal.


Here is the Detroit Locker, now by Eaton. If you are a rockcrawler or hardcore drag racer and want 100% of teh torque to be split EVENLY between both wheels, this is for you. It uses dog gears to apply torque to each wheel. The issue with this unit is that it makes noise in turns as the dog gears move over each other while unlocked. Over time the dog gears will wear, and the noise can be disconcerting to some.




I had a "similar"unit called a "lunchbox" locker made by Powertrax, its named the Lock-rite locker. It simply replaces the side and spider gears. I went through 3 of tehse before giving up. The initial mponey I paid for teh unit and the shipping from my place to the US for warranty I could have had a new Trutrac unit.

Here is the Lock-rite locker made by Richmond/Powertrax


A quieter version of the lockrite, its also made by Richmond/Powertrax, its called the No Slip Traction System.


Any of teh above Lockers oe Lunchbox lockers will behave as though there isnt a differential present at all. I have found that when driving on freeways at 60-70mph, that when encountering a gentle bend/curve that doesnt cause the dog-gears to disengage, with the lack of rear axle differentiation, the truck feels as though its fighting your steering inputs. Feels like its on rails in a negative way. Just an onservation though, its not bad on dry pavement, but I could see that getting dangerous in the Winter on snow/ice. These lunchbox lockers require the weak stock open differential as these units will NOT install into stock G80"Govlock" carriers.


There is also some lockers which are "locked" by air or electricity, so you can drive around normally, then when you need 100% traction, you flick a switch and the dif locks. They are made by Eaton(E-Locker) and ARB-Airlocker and others.

There are:
Lockers- Detroit Locker
Lunchbox lockers
Locking differentials- Govlock
LSD(Limited Slip Differntials)-G86, Eaton LSD, Auburn LSD
Torque Sensing-Eaton Trutrac, Torson
Spools-these allow for no axle differentiation -used for competitive pulling and drag only race vehicles
Lincoln Locker-welding the side and spider gears for a homemade spool
Dif Locks- ARB-Air Locker, Eaton ETEC

They are all traction devices

Here is a great photo of an Eaton Detroit Truetrac next to a stock open carrier. As you can see, it is MUCH beefier than the stock unit. The stock GM open carrier is strnger than the stock G80 Govlock becuase the G80 carrier has even less metal in its construction.



Make any additions I have missed.



peace
Hog

 

Sounds like trutrac is the way to go. I might swap in a trutrac an assassin bars an see how that helps me, then if I still need gears won't be anything besides swapping them in.

 

I had a eaton posi clutch style , and it blew like 10k miles later , the clutches. Burned up then I slaped in a a tru trac. And 30K miles later it still lockes like a champ

 

Ive had good luck with the Eaton LSD. Gettin close to 100k miles on it i think.
Its never let me down and ive had everything from 31x13.5 super swamper boggers on it for mud and dirt drags. To 28x10.5 hoosier slicks for the drag strip.
I havent had any dealings with the trutrac except from what the guys on here say about them.
Ive seen a few of them come apart in F-Body cars but thats it.

If i had to do it over, id go back with the Eaton. I spend more time off road than i do on it seems like and it comes in handy. I hated the G80. It sounded like one them lunchbox lockers while goin down a muddy road.