What's a good way to verify whether or not am M923A2 has lockers?

[insas]

Hello,

What's a good way to verify wether or not am M923A2 has lockers? I don't think mine does, however the turn radius seems quite a bit larger than other M923's I've driven.

Thanks!

 

[mattyboy]

you would need a big mud bog to tell or a RTI ramp ( ramp travel index). they can be seen at off road events as the rig climbs the ramp eventualy one wheel is going to leave the ground. no locker and that is it for truck but , i have yet to see a ramp that would support a 5 ton. hehhehehehehheheheh

 

[phil2968]

Just jack up one side of a rear axle. Grab the tire and give it a good turn back and forth. If it does not turn it is a open diff. If it unlocks and spins free then it will be a Detroit "no spin" differential.
The faster rotating axle shaft will unlock from the diff and remain so until the rotation matches again. Get it?

 

[Suprman]

I had a 923a1 with lockers you could feel them when accellerating through a turn. But I have a few trucks that I drive to compare it to.

 

[patracy]

Just jack up one side of a rear axle. Grab the tire and give it a good turn back and forth. If it does not turn it is a open diff. If it unlocks and spins free then it will be a Detroit "no spin" differential.
The faster rotating axle shaft will unlock from the diff and remain so until the rotation matches again. Get it?

Just a note, jack up one side of BOTH rear axles. You'll also need the truck "aired up" and parking brake off with it in neutral to confirm.

 

[Triple C]

Just jack up one side of a rear axle. Grab the tire and give it a good turn back and forth. If it does not turn it is a open diff. If it unlocks and spins free then it will be a Detroit "no spin" differential.
The faster rotating axle shaft will unlock from the diff and remain so until the rotation matches again. Get it?

if it spins it is a no spin? I thought I understood before but now I am confused.

 

[BKubu]

I have never heard of an M939A2 having lockers. The Army did not use lockers, and the USMC never used the A2s. The Navy did and they normally followed the USMC with lockers on earlier vehicles, but a USN Seabees truck that I had did NOT have lockers. I was hoping, though!

 

[mcmullag]

So the Marines used the M923a1 that maybe had lockers and it looks like a M923a2 but does not have CTIS? is that what is fooling some of us, the a1 looks like the a2?
View attachment 459787View attachment 459788View attachment 459789 sorry if I am causing anymore confusion in any way, do not mean too, just trying to clarify.

 

[BKubu]

Yes, the A1 and the A2 look almost the same. There are outward differences, however, most notably the A2s have four front lifting shackles, CTIS on the rims, and the bottom of the differential housings are flat (rounded on A1s). There are confusing things, though: I have seen a few rebuilt A1s with four front lifting shackles, and I've seen some A2s missing the CTIS components off of the rims. Those are the most visibly, outside, differences. Obviously, the A2 has the 6CTA motor while the A1s have the NHC250 (big difference visually, but you won't see that from 20 feet with the hood down). There are other more minor differences, but this captures the main things to look for.

 

[phil2968]

Just a note, jack up one side of BOTH rear axles. You'll also need the truck "aired up" and parking brake off with it in neutral to confirm.

It will work with just one side of one axle off the ground. Brakes are a different story, don't know anything about a five ton. Have done this test on a 2.5 Rockwell and it will unlock because you turn the axle faster than the carrier.

if it spins it is a no spin? I thought I understood before but now I am confused.

Yes it will unlock and spin free if it has a locker. If it will not spin it is a standard diff and is trying to turn the other side. Check this out.. https://www.youtube.com/watch?v=FYBOoljH-qE&feature=youtube_gdata_player
This test only works with the Eaton no spin locker. Other limiting diffs work differently.

 

[Triple C]

Wow phil2968, that video was incredibly helpful, thank you very much.

 

[KsM715]

Posted by phil2968. ( sorry forgot to hit reply with quote)
"It will work with just one side of one axle off the ground. Brakes are a different story, don't know anything about a five ton. Have done this test on a 2.5 Rockwell and it will unlock because you turn the axle faster than the carrier."



How is that possible on just one axle? If it has an open diff and you lift one tire and spin it, it should spin the drive shaft that connects the two axles. If the second axle is on the ground it won't spin which would result in someone thinking it has a locker in it.

 

[phil2968]

Yes it will unlock and spin free if it has a locker. If it will not spin it is a standard diff and is trying to turn the other side. ...
This test only works with the Eaton no spin locker. Other limiting diffs work differently.

How is that possible on just one axle? If it has an open diff and you lift one tire and spin it, it should spin the drive shaft that connects the two axles. If the second axle is on the ground it won't spin which would result in someone thinking it has a locker in it.

Eaton no spins unlock when one axle shaft is turned faster than the other.
The only diffs these axles had were open or Eaton no spins.
If you jack up both axles yes the open diff will spin the center driveshaft and the other axle. However, if you leave the other axle on the ground and just jack up one wheel on one axle and turn the tire if it has a Eaton no spin it will unlock and spin. If it won't turn it is open. The only way just one tire will turn is with a no spin or a busted open diff.

 

[KsM715]

Is the eaton unit the only type of locker that could be found in these trucks?

 

[patracy]

It will work with just one side of one axle off the ground. Brakes are a different story, don't know anything about a five ton. Have done this test on a 2.5 Rockwell and it will unlock because you turn the axle faster than the carrier.

The reason I added jacking both axles up is sometimes those lockers can be a pain to get unlocked. Having a non locked axle with both axles up would indicate very easily they're open since spinning one wheel will spin the other.

 

[insas]

Thanks for all the info guys. One reason I want to check is the truck has a noticeably larger turning radius turning one way vs the other... Has anyone else noticed the same?

-now I just have to figure out how to jack this sucker up... You know... My backs not quite what it used to be....

 

[TacticalDoc]

My truck has USMC painted on the hood, it also has a plate on the driver side door that says it has Detroit lockers and when I make a turn I leave tire marks on the road. It also make a rougher turn.