M925 making a strange noise

[VA 5Ton]

Do you have a cover on the bed? I have a similar sound that was driving me crazy so I had a buddy drive and I rode in the troop seats. I figured I could look around the spare and down to where I thought the sound was generated. I was surprised to find the noise coming from the bows of the cover. I have some of the newer Fiberglas bows and they are really noisy where the fit into the metal joiners.

I hope yours is an easy fix too.

 

[gimpyrobb]

How about your dog bones? Have you checked them at all?

Maybe its an axle issue. Pull the axles out of the housing and see if it goes away.

Have you looked over all the U-joints?

 

[Olpa77]

I have checked the dog bones and ever thing looks good there. U-joints LOOK good and tight but I am not ruling them out just yet. I guess I know what I am doing over the weekend. Pulling brake drums and possibly axles, thanks for the suggestion gimpyrob. As for the bows and cover it was making the noise before I installed them on the truck. I can live with something loose making noise, I just don't want it to be something mechanical that's going to leave me waiting on the side of the road for the rusty hook.

 

[Scar59]

You need to have soldier B drive the truck and get in the bed to source that rattle, it sure sounds like the davit trolly/spare chain. I know you have eliminated that. I had the same sound, however it was a small piece of chain wrapped around the spare and dangling against the frame support.

 

[Olpa77]

I had soldier A (wife) hop in the drivers seat. While soldier B (me) walked next to it at slow speeds and to me it sounded like it was in the transmission area. I have no clue why soldier A told me it was coming from the rear ends. I took a can of good old WD-40 and sprayed down the front driveline carrier bearing. Funny how the noise went away for 4 miles then slowly came back. So I'm going to start there. I'll let you all know when I replace the bearing to see if it corrected the issue. Thank you SS for the help. This is by far the greatest forum on the net.

 

[74M35A2]

Noises like this are fun. As they get louder, something will eventually fail, and then you'll know what it was and can fix it.

 

[Scar59]

Carrier bearing can get real noisy , good trouble shooting, I listened to the video again, you're on the right track.

 

[Olpa77]

I have one ordered. When I replace it I will let you know if that's what is was. I am pretty sure its the bearing. Did some driving yesterday and every time we heard it I sprayed it with WD-40 and it would stop. This really is a great site. I enjoy the search feature and TM's. Hopefully this thread can help someone with their rig in the future.

 

[m1010plowboy]

Have you washed her lately? One of my noises was a lawnchair in the back. Cleaned out the truck, greased it and the noise went away.

Hopefully the WD40 found it and a guy can breath easier knowing that it doesn't sound like that little flappy piece in the transmission.

We use a wood dowel as a stethoscope. The things you can hear through a 1" piece of closet dowel or a broom handle is surprising. Not sure how you would 'safely' do it driving down the road but after a little hazard assessment and not sticking the dowel in a turning u-joint, it may help. Pops showed me his 'diagnosis' tool decades ago trying to decide if it was the alternator, power-steering pump or water pump bearing that was making the noise. I can almost hear which lifter is making a noise in the M135 and you can hear the bearings turn when you're on the engine block, very cool. Even as a kid I thought it was nuts sticking ma's broom handle under the hood with the engine running so whatever you do be safe and good luck on the fix.

 

[Olpa77]

I changed the carrier bearing today and the noise went away. I guess that solves that problem. The new bearing has some slight up and down play. Is this normal?

 

[R Racing]

No it really shouldn't. Did you tighten the pinion bearing nut really tight? And did you notice any broken thrust washers?

 

[R Racing]

In and out play yes if it's less than .018 up and down no play.

 

[Olpa77]

No it really shouldn't. Did you tighten the pinion bearing nut really tight? And did you notice any broken thrust washers?

I could'nt get the old one off so I ran the drive line over the Inland Truck Parts, they do awesome drive line and transmission work.When I installed the drive line back on the truck I can push it up and down a little at the bearing.

 

[Doug Roberts]

The clicking sound you're talking about cycles on and off just before the air brakes purge . Mine do it too , and I think I remember it being addressed and it just got by me . I'd like to solve it myself , but that's the clicking sound you're hearing I'm sure.