Need help identifying this carrier

[Jorwood]

Just bought this Chevy Dana 44. Guy said it had an air locker. There's an air fitting threaded into where the vent tube went. The diff seems open but after blowing some compressed air without a sealed connection it starts to spin both axles like it's almost locked. The only marking on it are the letters "JD" stamped inside the cut out of the carrier. Can't tell if it's just a limited slip or if it's actually an air locker or possibly just a lunch box locker. The carrier does not look like a standard 44 though...
https://ibb.co/ByS223M
https://ibb.co/tpw5Sf7
https://ibb.co/DRyV0yV
https://ibb.co/XVYjbKD

 

[tRustyK5]

I'd guess air locker. Why else have the air fitting? No fake style points to be gained. It is definitely a full case, aftermarket piece. You will have to get a good sealed air supply to that line...then it should be even more obvious.

 

[Jorwood]

Little more research has me thinking it's a Detroit true Trac

 

[Hogback Fabrication]

First picture sure looks like a true trac, and I don't see an air line anywhere in there.

 

[Blue85]

Looks just like some of the Truetrac pictures, including the helical gear being visible in one pic.

Confusing part is that both air locker and Truetrac will test like an open diff - except apparently sometimes they kinda don't. It's not unusual for people to thread different fittings to an axle to facilitate routing the diff vents to different locations. You could postulate that the air locker was removed at some point, but if that was the case, there should be both the air line AND a vent line.

 

[frankin5]

Could be a Dana tracloc

 

[sweetk30]

Looks just like some of the Truetrac pictures, including the helical gear being visible in one pic.

View attachment 298664

Confusing part is that both air locker and Truetrac will test like an open diff - except apparently sometimes they kinda don't. It's not unusual for people to thread different fittings to an axle to facilitate routing the diff vents to different locations. You could postulate that the air locker was removed at some point, but if that was the case, there should be both the air line AND a vent line.

View attachment 298662

x2

 

[campfire]

Looks just like some of the Truetrac pictures, including the helical gear being visible in one pic.

View attachment 298664

Confusing part is that both air locker and Truetrac will test like an open diff - except apparently sometimes they kinda don't. It's not unusual for people to thread different fittings to an axle to facilitate routing the diff vents to different locations. You could postulate that the air locker was removed at some point, but if that was the case, there should be both the air line AND a vent line.

View attachment 298662

Those directions just say to check for opposite rotation. My open axle does that already. What would this tell me about a truetrac? Seems like it would never deviate unless it failed in the non-default locked position. Is this a likely situation? Or am I missing something?

I think it would be a more useful test for a normally-locked Detroit locker.

 

[blazinzuk]

It's not an air locker. It's a Detroit Tru trac

 

[Blue85]

Honestly, I'm pretty confused by that part of the Eaton manual. By their statement, the driveshaft is fixed, which means the carrier isn't turning. There should therefore be no interaction between the left and right sides.

 

[campfire]

Honestly, I'm pretty confused by that part of the Eaton manual. By their statement, the driveshaft is fixed, which means the carrier isn't turning. There should therefore be no interaction between the left and right sides.

Don't the helicals differentiate like normal spiders?