Posi unit recommendation for 12bolt

[Luke87gt]

Hi guys, I have a 69 c10 with 3.73 (i6) and starting to plan a removal and overhaul.

While I’m in there I’d like to upgrade to a posi unit.

Wondering what the popular ticket is these days? Eaton? Other?

I’m looking for something that will be comfortable on the street but strong /durable.

Thank you

['68OrangeSunshine]

About the Mid-Ninties I had the 12-Bolt 3.73 rear end go out on my '67 K/10 Suburban. It had a 454/TH350/NP205/3.73 drivetrain. Bearings went out after unknown mileage. A PO had already used Bearing Savers.
I had the whole carrier rebuilt. Moser axles, since I couldn't get OEM 6-lugs bc the plant had a strike going with the UAW. I went with an Auburn Posi. I spent around a thousand 30 years ago. The Sub had an engine fire [ '98] and a big insurance company totalled it for me and I got a Salvage Title. So it sat. In 2010, the stock Eaton posi on my K/1500 GMC Jimmy, broke, trying to pull a deadbeat's Scouts off my property.
We cannibalized the whole rear end off the '67 Suburban and bolted it on the '71 Jimmy.
I know the widths differ between the years. Somehow, we got the skinnier '67 carrier under the '71 chassis. Putting the '71's carrier under the '67 chassis didn't work. It's still on jacks.
But the point is I've had real good luck with my Auburn. It's run on two trucks. You can't rebuild them, they say. Eatons are good too, and rebuildable. But I haven't had to rebuild an Auburn.

[WorldsCrappiestTruck]

I did an Eaton TrueTrac a few months ago - pleased with it so far.

[truckster]

I'm very happy with my TrueTrac. I forget it's there until it's needed and then it does its thing without any problem.

[A1971Blazer]

Another vote for the TrueTrac, it's probably the most street friendly unit. No need for friction modifiers like the clutch type. I have them in two of my trucks.

[72SB]

Go Eaton, not Auburn.

If you are switching to higher gear ratio, you will need a different carrier size than the 3:73 IIRC

[GASoline71]

Anything made by Eaton is good. Auburn's are okayish but they are not rebuildable like an Eaton.

Gary

[truckster]

Originally Posted by GASoline71

Anything made by Eaton is good. Auburn's are okayish but they are not rebuildable like an Eaton.

Gary

That's one of the beautiful things about the Truetrac. There's nothing to wear out so there's nothing to rebuild.

[bry593]

Brian also votes for Eaton True-trac helical locker.

This has no clutches to wear out and does not require limited slip additive. Just use regular old 75w90 gear oil.

Another cool thing is that unlike a traditional locker, you don't have to worry about getting off the throttle before entering a corner. The true-trac acts like an open differential until there is a rotational difference between the wheels.

A bad thing about this design is that it will not lockup if one wheel is completely without traction. For example, if one wheel is in a low mud hole, it will just spin. The fix is to lightly apply some drag to the spinning wheel (use the brake pedal) and it will lock right up.

Anyway, this is the best you can get for a daily driver. If you are off-road or really trucking, get a Detroit Locker. These are bullet proof and deliver 100% torque to both axles. They do require some thought about how you drive or you can have a really bad day. If you approach a corner nearing the limits of your handling, as soon as you left off the gas in the apex, the locker unlocks and this throws the dynamics of the chassis off. Can cause you to lose control.

[LS short box]

I'm a Tru Trac guy. Upgraded to the 30 spline unit as needed depending on the vehicle and 30 spline axles from Moser.
Also the Tru Trac doesn't need any posi additive.