# tru trac locker



## plowin207 (Jan 21, 2010)

I'm kind of debating with my self on getting a tru trac locker for my truck it is an 01 GMC Sierra. i do some off roading. But i hate the one wheel spin whether it be on the road or snow or off-road and just wondering if anyone has experience with these on and off road but also plowing I'm wondering if plowing with it will break things or if it will be fine thanks in advance for the advice


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## B&B (Nov 4, 2006)

A Tru Trac is a limited slip diff, not a locker. Won't lock the axle 100% together like a locker. But they're very smooth in their action and work great in a plow truck since you're travailing mostly on slick roads where a mechanical locker can cause handling quirks. 

You'll never hurt it either as they're very well built. You'll break something else in the drive line first.


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## bacwudzme (Sep 13, 2009)

My buddy just got a Tru Trac this past fall and his truck is now a horse of another breed! He got it in sept. and flogged it all oct. bird hunting up north and he said what little snow we've had a made a huge improvment.
He ordered it from Archies off road in wells and had a shop in rt.1 that Archie recamended. He was very pleased with everything so far. My buddy wanted a Detroit locker but Archie talked him out of it.


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## gamberbull13 (Dec 16, 2009)

have one in my 95 half ton and really like it, its really smooth. much more streetabl than when my locker engages on my crew long when i turn sharp on gravel roads and slightly slick snow dustings on blacktop


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## 2COR517 (Oct 23, 2008)

Is the Tru Trac a drop in install?


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## B&B (Nov 4, 2006)

No, it's a complete new diff carrier necessitating checking/resetting gear set clearances. But they usually set up very easily and close to original spec so their quality control is good.


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## 2COR517 (Oct 23, 2008)

Eaton application guide shows the Tru-trac fitting Dana 44 fronts up through 80 only. What happened in 81?


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## B&B (Nov 4, 2006)

2COR517;1004381 said:


> Eaton application guide shows the Tru-trac fitting Dana 44 fronts up through 80 only. What happened in 81?


They were all 28 spline corporate 10 bolts by then in trucks that previously used a 44. If you have an '81 with a 44 it isn't original to the truck or the cab/VIN has been changed.


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## plowin207 (Jan 21, 2010)

so i kind of understad that it isn't a full locker and the difference between the limited slip and the full locker. another question i have is say im going around a corner on wet pavement,dirt road or snow and really give it some gas will it spin and keep both wheels spinning to drift corners or will it not lock and resort back to the one wheel spin not that i do this on wet pavement but sometimes on snowy roads if there is anyleft before or after i plow i try to keep goofing off off-road and don't even do it alot then cause i can't afford to be fixing things i broke while f"***ing off in my dd and work truck


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## plowin207 (Jan 21, 2010)

and i have been trying to figure out what one i would need i know i have a 10 bolt rear end with 3.73 gears but im not sure what the spline is or the 8.5, 8.6, 9, rearend mean


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## B&B (Nov 4, 2006)

plowin207;1004396 said:


> so i kind of understad that it isn't a full locker and the difference between the limited slip and the full locker. another question i have is say im going around a corner on wet pavement,dirt road or snow and really give it some gas will it spin and keep both wheels spinning to drift corners or will it not lock and resort back to the one wheel spin not that i do this on wet pavement but sometimes on snowy roads if there is anyleft before or after i plow i try to keep goofing off off-road and don't even do it alot then cause i can't afford to be fixing things i broke while f"***ing off in my dd and work truck


 Yes if you get on the throttle hard enough to spin them a TruTrac will put power to both wheels.....so donuts are no problem.  The one instance where they're a little slow to transfer power is when you're in a situation where traction is grossly different from one wheel to the other. For example one tire is on pavement but the other is on ice. In a situation like that they take some extra throttle input or a light press of the brake pedal to even out the turning resistance between the two tires. Otherwise they shine for poor road conditions which make them perfect for a plow truck.



plowin207;1004401 said:


> and i have been trying to figure out what one i would need i know i have a 10 bolt rear end with 3.73 gears but im not sure what the spline is or the 8.5, 8.6, 9, rearend mean


What exactly is your '01 GMC? 6 lug 1500? 8 lug 2500? Need to be more specific.


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## 2COR517 (Oct 23, 2008)

More durable than a Gov Bomb?


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## B&B (Nov 4, 2006)

2COR517;1004483 said:


> More durable than a Gov Bomb?


_Mulch mulch_ more.


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## Detroitdan (Aug 15, 2005)

I remember an old-timer telling me not to put a locker in a plow truck because on a sidehill both tires would spin allowing the rearend to slide out, whereas a one-leg would allow only one to spin and the other tire would hold you on he hill. I actually thought it made a little sense back then when I was a teenager, but since then I've seen holes in that theory. For instance, in quite a few years of residential plowing I've yet to have to plow any sidehills. Secondly, plowing in simplified terms is basically a big piece of metal (plow) catching as much snow (weight) in front of it as possible, which wants to stop the machine pushing it. Said machine has a finite number of drive wheels, each in their attempt to push the load in front of it using only a relatively small contact area with a slippery surface. Methods to counteract the inherent traction problem to allow the machine to move the load further include but are not limited to: premium tread design, weight (ballast) over aforementioned tread, 4 wheel drive capability (which is usually adding only one to your pre-existing one or two wheel drive). Of lesser importance is torque and horsepower, but you will need to have some. 
The way I look at it is, a locker isn't there to "spin both tires", it's there to have the second one keep the first one from losing traction and spinning. Or in my case, the 3rd and 4th tire to keep the 1st and 2nd tire from spinning.

My first plowtruck was a 3/4 ton with 3:73 open differentials. My second truck and my current truck both came with 4:10s and rear lockers. IMHO, there is no conceivable reason to waste your time trying to plow with anything else. That's just been my experience. I have never had a locked front axle, but I am pretty sure I wouldn't want one for plowing. As it is I have to disengage 4wd to turn around in tight spots.

As a point of comparison, both my first and second plowtrucks were essentially identical trucks. 3/4 ton regular cab, SBC automatic with Fisher conventionals. Only major difference was the axle ratio and locker; also the first one had a slightly modified 350, the second one had a tired, high mileage 305. That second truck was a monster of a plowtruck, the first one would move snow but not without beating the hell out of it.

This was a really long goofy post. What I should have said is this: Get the locker, you won't regret it. I have plowed with both open and locked and found the locker plows better.
There.


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## B&B (Nov 4, 2006)

Detroitdan;1004618 said:


> This was a really long goofy post. What I should have said is this: Get the locker, you won't regret it. I have plowed with both open and locked and found the locker plows better.
> There.


I know guys often intermix the terminology and that's where the misunderstandings stem from as far as what a limited slip is and what an actual locker is that has the capability to physically lock the axles together and/or never allow one axle to turn slower than the ring gear is rotating. A Tru Trac for example isn't a locker, it's a helical gear limited slip (no clutches to wear out is a big plus). A limited slip and a locker are two completely different things with different operating and handling characteristics.

What brand/style diff are you running in the rear Dan?


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## Detroitdan (Aug 15, 2005)

My 81 had a Detroit locker in it, this 97 just has the factory style locker in it. Using your terminology it may be in fact a limited slip, but my terminology has always called it a locker, as the build sheets from GM refer to it as a "locking differential". I guess if it has the capability of locking and unlocking I'd call it a locker, whereas some wouldn't. I had a big-block Camaro with a limited slip, and it was obvious it couldn't perform like a locker.
In your post you say "never allow one axle to turn slower". Maybe I'm understanding it wrong, but a fully locked rear axle, such as a welded or "Lincoln locker" would do that, as would most of the racing style spools, but I think many of the traction devices such as Detroits are automatic lockers. Just because they can unlock doesn't mean they aren't a locker, and doesn't mean they are a limited slip.
Is this correct?
If what you were referring to above was the terminology "locker" used in conjunction with the original posters tru-trac, then I see where I strayed off course. In post 2 you pointed out it's a limited slip. I'm not arguing that, and I guess my long rambling post about plowing with a locker kind of went past that.


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## Detroitdan (Aug 15, 2005)

I vaguely remember reading somewhere that the 97 3500 14 bolt full floater would have come with a gov-lock. I know the gov-locks in the half tons were known for being grenades, but this rearend has been extremely stout. The more I think about it, the more I think this rearend is supposed to have an oil additive, which would mean it's probably a lsd as opposed to a locker. I have noticed it ratcheting loudly a couple times on ice, but other than that it works unnoticeably, always pushes the truck forward no matter what the circumstances. I don't think I have ever spun just one wheel.

My 81 had the more well-known handling characteristics, slowing down then turning you would feel it try to push it forward before unlocking and allowing it to turn. More noticeable in the summer with the 35tires on it.


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## B&B (Nov 4, 2006)

Any diff that can mechanically and physically lock the axles together and under no circumstances will allow either axle to turn slower than the ring gear is a locker, whether it be mechanical (Detroit Locker, LockRight etc) or driver selectable such as an Eaton E-locker or an ARB air locker. Any other type of diff that can also differentiate power the wheels is in the LSD category. Spools are not lockers as they can't release the axles from one another so they provide no differentiation to the axles, a locker has the capability to release the axles from each other such as in a turn, a spool can't. And that's why they each have their own category.

The factory GM GovLoc's are bit different and require their own category in that they're of both an LSD and a true mechanical locker since they act and function like a loose clutch type LSD until wheel speed differentiates enough for the governor (it's a centrifugal flyweights assembly on a rotating shaft geared to the side gears) to ramp the wedge plates into the clutches, thus clamping them tight to the diff carrier so they can't spin slower than ring gear speed and hence the same performance as a true mechanical locker. So they'll allow smooth wheel speed differences for good driveablity like an LSD until there's enough wheel spin to physically lock the diff and perform like a 100& locking differential. And they work quite well most of the time but are well known to explode (hence the nickname Gov-bomb) without warning. The 10 and 12 bolts are easy to blow up but the 10.5" 14 bolts are a little tougher, but they'll blow up too. I've had to torch many of them out of the housing after they let loose after guys had them stuck and worked them hard to get them out. Most blow up due to extreme wheel speed differences (hard throttle jockeys basically) before they have a chance to lock the axles together...and once they attempt to BANG...they explode. Guys blow them up in the 11.5 AAM axles too if pushed hard enough.

So they're fairly tough in the larger rears but still far from indestructible. They're also well known in the 10's and 12's to lock but not unlock thus dragging tires around corners with the audible chirp (like when running a spool or mechanical locker on the street) and will sometimes break an axle shaft because of it.

I've blown a few up myself too.


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## plowin207 (Jan 21, 2010)

its a 6 lug 1500


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## B&B (Nov 4, 2006)

Then you would have the 8.6" 30 spline 10 bolt.


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## plowin207 (Jan 21, 2010)

thanks B&B


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## bacwudzme (Sep 13, 2009)

Are you going to give Archies a shot. I bet there 20-50 dollors cheaper than you can get online. My Buddy is in Jackman right now so I dont know any details.
He gets Posi so to speek every time he tromps on the gas!


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## plowin207 (Jan 21, 2010)

ya i was actually just in there today and ordered shocks from him and was going to ask him about that and a couple other things but he was by himself and like three other people came in so im gonna find out when i go to pick up my shocks. and when i do save up the money to do this i will probably go thru him cause i am all for supporting local business rather then some huge online store or huge box store etc...


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## bacwudzme (Sep 13, 2009)

Where you located if you dont mind me asking?


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## dmontgomery (Oct 3, 2003)

I have a Tru Trac LS in my 05 Ram 2500 CTD.........love it.......with the right amount of weight I can plow anything in 2 wheel drive........it is also nice for towing on wet pavement.......


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## plowin207 (Jan 21, 2010)

im in kennebunk/kennebunkport


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## ieetgluu (Dec 7, 2011)

So, to bring this thread out of retirement, would this be the correct tru trac for a 3.73 10-bolt in an '03 1500?
Or is Tru Trac different from TrueTrac? I notice this is also called locker and not lim. slip

http://www.jegs.com/i/Detroit-Locker/357/913A481/10002/-1?parentProductId=1032953


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## carkey351 (Oct 18, 2010)

not to hijack this thread, but my dmax truck has a G80 RPO code and I'm wondering if it is worth replacing (think it may be shot-seems to act like a 1 wheel wonder...) with another G80 or if a tru-trac/detroit locker would be better??


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## B&B (Nov 4, 2006)

ieetgluu;1427549 said:


> So, to bring this thread out of retirement, would this be the correct tru trac for a 3.73 10-bolt in an '03 1500?
> Or is Tru Trac different from TrueTrac? I notice this is also called locker and not lim. slip
> 
> http://www.jegs.com/i/Detroit-Locker/357/913A481/10002/-1?parentProductId=1032953


Detroit Locker is a brand name now, and Trutrac is a product in that brand line. So your link is to the Trutrac limited slip diff and yes that's the correct unit for the 99-up 8.6 10 bolt.


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## B&B (Nov 4, 2006)

carkey351;1427760 said:


> not to hijack this thread, but my dmax truck has a G80 RPO code and I'm wondering if it is worth replacing (think it may be shot-seems to act like a 1 wheel wonder...) with another G80 or if a tru-trac/detroit locker would be better??


Depends on what you do with the truck but personally when the Gov-Bombs blow up or wear out I generally replace them with a Trutrac. Much smoother operation and last forever. The only disadvantage is a little less guaranteed traction per wheel. But it's seldom an issue on a street use vehicle.


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