M920 Rear End "Clunk" Noise

[Thomas_G]

Have a M920 with a clunking noise at the front rear end at 30 MPH, i think its safe to say need a new one, anyone know of a take out available?

 

[country]

We have a parts truck we can pull a differential from

call our office 855-332-0500 or email dave@easternsurplus.net

 

[Postman515]

Locker may not be unlocking.

 

[simp5782]

Pull the shafts and see if it goes away. If it does then you may have a locker problem. Have you noticed if the axle is pulling or not ? Help to post a video of the "clunk" Noises do radiate pretty bad with all the steel so it could be hard to pinpoint. Also post a pic of the axle tag. Should be something along these lines

A 3121 N 378

137/80

Rockwell international

 

[Thomas_G]

Well from what I can tell it did not pull to any side. The noise was prominent from the front rear end, like a banging noise from hitting something. the truck was just service and there was no bad U-Joints.

 

[simp5782]

A truckprothere may have the parts or there is a drivetrain/axle shop more than likely in Houston. If you have your tag number you can probably get all the internals pretty easy. The one here in Memphis is 901-332-7000.

 

[simp5782]

Also the front rear axle if it is screwed up will not pull to one side being that is in not a directional axle if your front end was doing it then yeah it may pull to one side. Your rear axle goes wherever the front goes and doesn't pull to one side. You could tell of tire wear if it was pulling to one side but that would take awhile.

 

[Thomas_G]

How would one check the locker on a 920?

 

[NDT]

How would one check the locker on a 920?

Use a bottle jack to raise the left side of the intermediate axle and a second one to raise the left side of the rear axle. Put the truck in gear, if the wheels in the air spin, you have a bad locker or no locker. If the truck drives off the jacks, all is well.

 

[M2Guy]

If it only clunks 1 time with each change of steering direction it may be a/the torque arm bushing/s for the rear axles. When the bushings are starting to go you will get a clunking noise that is very hard to diagnose.

 

[Thomas_G]

I lifted up the rear axle and spun it with truck in neutral, brakes released. You could turn left rear tires and here a slight "clunk" noise then the drive shaft would like catch and then start turning. Performed action on both sides. I have a few videos attached.

The truck does not pull to anyside, no bad u-joints.

 

[simp5782]

I can't watch the movie. I don't have an app to support it. If you took it with your phone just text it to me 901 318 8353 and ill upload it to youtube so everyone here can see it.

 

[simp5782]

https://youtu.be/FJ2VF6_VbpU

Sent from my SM-G860P using Tapatalk

 

[Castle Bravo]

Earlier this year, I had the rear axles of my M916 off the ground and from what I can remember, spinning them made this noise as well. That should be the Detroit locker clicking as the one side is overrunning the other.

 

[Thomas_G]

I will try to get a video of the noise when driving. noise starts at around 25 mph and progressively gets louder at 30 and higher, then when you slow down it decreases in noise.