Eaton TrueTrac or Detroit Locker? Which gets the nod?

[daveyRocket]

I am planning to upgrade my open diff to a posi or limited slip. I have been researching this topic for a couple weeks. My truck is an 88 lwb 5.7l c1500 with 8.5 rear 10 bolt and 3.42 gear. It has tbi and a well worn in rebuild. Motor is great. I plan to replace some valve stem seals on the 5.7l but not much else for now. It has great low end and that's all I really need. I just got it back from a few years at my son's place. I have been fixing things: New tires 235/75r15 and Chevy wheels 15", New windshield, new stereo, cover for bench seat, fixed some broken interior pieces. I am dying to turn this truck into a full size mid life crisis but my grown son, the mechanic, is begging me to keep the tbi for simplicity.

Im thinking a 2/4 drop with spindles and springs/ flip kit for the rear. Unfortunately I have not been able to find the video where they show the lowered truck hauling a refrigerator. I know there are air ride load supports available too. Just find that video of the refrigerator and send it to me ok?


The Chevy's open rear was great when I was hauling mower trailers and such. Its not so great when you get stuck in your neighbors yard during a tailgate party. Most of the vids say the G80 was the king of Chevy limited slip. I was going for the clutch pack idea but was quickly talked out of that. I have heard that the Truetrac is Eaton's replacement for the G80. I like that it is wheel speed sensing. I think it will help me in light snow and gravel parking lots at camping and picnic sites in the mountains. I have also seen that the locker is great for 4wd but has some street characteristics that are not so great. My current setup spends most of its life below 2500 rpm. I want a great limited slip that will last for years. I also want to future proof the truck in case I later decide to go full mid life crisis and build a dropped blown pro street truck.

I know there are a lot of very good manufacturers out there. You may prefer another. Which do you like? Which gets the nod?

 

[Frank Enstein]

TrueTrac in a heartbeat. It's smooth, quiet, and invisible until you need it. Use any gear lube you want (synthetic will make it slip a little more) no clutches to need friction modifier. Always my first recommendation unless you are rock crawling, then it's the Detroit locker every time.
Lockers are clunkier and noisier and they cost more. They are bombproof however. That being said, the TrueTrac doesn't break either.
I have been selling both for over 20 years. Stick with the TrueTrac and you can't go wrong.

Before you buy anything check the outside diameter of the carrier bearings they come in 2 sizes 2.891 and 3.062. You will need to know before you get the install kit. I also recommend a solid spacer and shim kit instead of a crush sleeve for the pinion bearings. Easier to set up, torque down, is reusable, and is stronger.

I recommend the Ratech kits over all others. Summit Racing has all of this and usually in stock too.

If you are changing the ring and pinion gears get 5 qts. of gear lube and an extra cover gasket because you will be changing the gear lube after you break in the ring and pinion.

If you still want to do the locker get the Redline heavy weight shockproof gear lube. It will cushion the the metal to metal contact which will quiet the locker racket a bit.

 

[mtl111]

TrueTrac in a heartbeat. It's smooth, quiet, and invisible until you need it. Use any gear lube you want (synthetic will make it slip a little more) no clutches to need friction modifier. Always my first recommendation unless you are rock crawling, then it's the Detroit locker every time.
Lockers are clunkier and noisier and they cost more. They are bombproof however. That being said, the TrueTrac doesn't break either.
I have been selling both for over 20 years. Stick with the TrueTrac and you can't go wrong.

Before you buy anything check the outside diameter of the carrier bearings they come in 2 sizes 2.891 and 3.062. You will need to know before you get the install kit. I also recommend a solid spacer and shim kit instead of a crush sleeve for the pinion bearings. Easier to set up, torque down, is reusable, and is stronger.

I recommend the Ratech kits over all others. Summit Racing has all of this and usually in stock too.

If you are changing the ring and pinion gears get 5 qts. of gear lube and an extra cover gasket because you will be changing the gear lube after you break in the ring and pinion.

If you still want to do the locker get the Redline heavy weight shockproof gear lube. It will cushion the the metal to metal contact which will quiet the locker racket a bit.

Outstanding write up! +1 for the Detroit Truetrac, got one in my 99' 2 door Tahoe, it 's been great!

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[daveyRocket]

TrueTrac in a heartbeat. It's smooth, quiet, and invisible until you need it. Use any gear lube you want (synthetic will make it slip a little more) no clutches to need friction modifier. Always my first recommendation unless you are rock crawling, then it's the Detroit locker every time.
Lockers are clunkier and noisier and they cost more. They are bombproof however. That being said, the TrueTrac doesn't break either.
I have been selling both for over 20 years. Stick with the TrueTrac and you can't go wrong.

Before you buy anything check the outside diameter of the carrier bearings they come in 2 sizes 2.891 and 3.062. You will need to know before you get the install kit. I also recommend a solid spacer and shim kit instead of a crush sleeve for the pinion bearings. Easier to set up, torque down, is reusable, and is stronger.

I recommend the Ratech kits over all others. Summit Racing has all of this and usually in stock too.

If you are changing the ring and pinion gears get 5 qts. of gear lube and an extra cover gasket because you will be changing the gear lube after you break in the ring and pinion.

If you still want to do the locker get the Redline heavy weight shockproof gear lube. It will cushion the the metal to metal contact which will quiet the locker racket a bit.

Summit Racing and Eaton's website say that the Truetrac is not available for my application What gives?

 

[df2x4]

Summit Racing and Eaton's website say that the Truetrac is not available for my application What gives?

Not sure how you're looking them up exactly, but the relevant part numbers for the TrueTrac are right here on page 10 of this PDF.

https://www.eaton.com/content/dam/e...ormance-differential-application-guide-en.pdf

You'll need to determine if you have 28 or 30 spline axles, but they make TrueTracs for both applications.

 

[mtl111]

I ordered mine from 4 Wheel Parts during one of those " no tax" weekends they have. This is the one I have for my 99' 2 Door Tahoe.
Eaton 913A481 Detroit Truetrac 8.5" 30 Spline Differential with 10 Bolt for GM

My diff is the older 8.5 like yours and has the smaller carrier bearings. You will have to know if you have 28 or 30 spline axles though. Detroit has a TrueTrac for 28 spline axles too, different part number. Prices seem a little higher than what I paid a year ago. Seems like I paid about $480.



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[Frank Enstein]

It should be 28 spline. The 8.5 10 bolt went to 30 splines in 89. I would check the spline count when you check the bearing diameters.

 

[Frank Enstein]

DTL-912A556 from Summit

 

[daveyRocket]

Cool. Thanks a bunch. I just wanted to know as much as possible so that when I go talk to the shop I can tell them exactly what I want.

 

[Zx1000hd]

I love my Spartan locker. It's over Half the cost of a true trac and takes about 2 hours to install yourself.