Anyone ever had issues with the Transmission mounts on the M900/923A2 series trucks?

[Oldworldtenacity]

So, I have had this ongoing issue with my M923A2 ever since I bought it back in Feb.

The problem is that there has always been a metal clanging sound that comes from directly underneath the cab where the Transmission is and it comes and goes when I take the truck out every week.

Some weeks it does not make a sound and is perfect. The past few weeks it has returned again and started to do it when you go over speed bumps even...and I can feel something clanging against the bottom of steel on the bottom of the cab when I go over bumps....still comes and goes though.

The only thing underneath that part of the cab is the Transmission...so I was thinking maybe the mounts perhaps?....

Anyone else had any experience with this type of problem on these trucks that can make a suggestion so that I may get this problem resolved.

The truck has always shifted fine....it's just something has always seemed a little loose under the cab in the drive train

 

[98G]

There have been trucks with mounts missing entirely. ..

 

[gimpyrobb]

Have you checked to see if the bolts are loose?

 

[Oldworldtenacity]

There have been trucks with mounts missing entirely. ..

WOw, did not know that.

 

[Oldworldtenacity]

Have you checked to see if the bolts are loose?

I looked up at the one mount that I could see attached to the cab reinforcement and it did not look loose or like it had been taking abuse against the cab, but I am not knowledgeable when it comes to heavy truck drive trains. That's why I thought I would ask before I take it to a garage and spend money when I don't even know what the problem is. I looked underneath the cab area with a spotlight and could not see anything loose or any damage....so I am puzzled so far.

 

[Scar59]

Take a look at the carrier bearing that supports the front drive shaft, they make a clanging /rattle noise that comes and goes w/ bumps.(when then bearing is loose/wearing).

 

[Oldworldtenacity]

Take a look at the carrier bearing that supports the front drive shaft, they make a clanging /rattle noise that comes and goes w/ bumps.(when then bearing is loose/wearing).

Ok, definitely going to check that today. The rattle gets worse if I accelerate quickly when making turns. Will report back.

 

[Oldworldtenacity]

Take a look at the carrier bearing that supports the front drive shaft, they make a clanging /rattle noise that comes and goes w/ bumps.(when then bearing is loose/wearing).

Yep, you were right....you could not tell from looking at it under the truck, but another mechanic took a ride with me this morning and as soon as we pulled out he said..."yep, its definitely your carrier bearing"

It seemed to be even worse today as every time I accelerated it would grind more and rattle more than just coasting. Going to order one now.

Appreciate it much!

 

[Scar59]

Good deal, I have a bearing on my M925 doing the same thing, found the part on flea bay, got it for less than $50. They are available commercially also. Now find a pair of front axle drive hubs and de-spline them. Install and you have poor man lockout front hubs. Keeps the wear and tear off the front drive line.

 

[Oldworldtenacity]

Good deal, I have a bearing on my M925 doing the same thing, found the part on flea bay, got it for less than $50. They are available commercially also. Now find a pair of front axle drive hubs and de-spline them. Install and you have poor man lockout front hubs. Keeps the wear and tear off the front drive line.

Ha, yeah that's where I ended up buying mine yesterday for $42 shipped. I hear ya on the poor man's hubs lol.