M923A2 transfer case front output question.

[Cobra03]

I got my 923 in December, and when I drive it, it is so loud. I thought it was nature of the beast. I would have to wear earplugs. This thing shook, shimmied, banged down the road. I checked all ujoints, ok. I noticed that the output flange on the front driveshaft was leaking really bad. I removed the front driveshaft and noticed that the output flange has a ton of play causing the seal to leak. At the time I couldn't get the nut off the flange with my 1/2 inch impact. I haven't had time to put my 3/4 on it yet. Is there a way to tighten or shim this? Do I replace a bearing? Replace transfer case? I will attach a video on here. I drove the truck home from work(40miles) and it drove like a dream with the front driveshaft out. It had minimal tire noise, but that was it! It drives like I always thought it should sound. I would rather not put a transfer case in it. What do you guys think?
https://vimeo.com/161219441

 

[Swamp Donkey]

If there was a substantial change in tire noise, ride quality and handling when you removed the front driveshaft then I would suspect the front axle has been engaged the whole time. Many of these trucks had the front axle shift cylinder plumbed wrong causing this. It would also explain excessive wear on the front output shaft bearing and seal.

To test this is easy since the front drive shaft is removed. Run truck until you reach full air pressure. Verify dash switch is in the OFF position. Try to turn the flange on the input shaft. If it turns then it's not engaged, which is good. If it doesn't turn then you need to check the plumbing to the cylinder on the T-case.

 

[Scar59]

Some of the M939 series trucks are equipped with a large carrier bearing supporting the front drive shaft. Known early fail point and makes a heck of a rattle noise.
Is this truck so equipped?

 

[Cobra03]

I will check this weekend with it running if the out put flange is free or not. It does not have a carrier bearing on the front driveshaft. But I am going to buy one. I have heard from multiple people that with a good carrier bearing they drive nice. From what I have heard.

 

[Monkeyboyarmy]

I'll tell you exactly what it is. There is a bad bushing on the back side of that front output shaft. I repaired one by splitting the transfer case in the truck. The rear half of the transfer case stayed in the truck still bolted to the mounts. Removed and replaced the bad bushing and reassembled. It was definitely a tough job, especially in January in Ohio, but it is possible.

 

[juanprado]

I believe only the nhc250 had the hanger bearing.

 

[Cobra03]

The NHC250 is the only one with the front carrier bearing.

Monkeyboyarmy, I was afraid of that. I guess I will just find a new transfer case and replace. Then fix mine in the floor and have a spare.

I have seen a bunch in Oklahoma on GL. Does anybody know what the going auction price is?

 

[Jason O]

Monkeyboyarmy-

I'll be replacing the same bushing on my transfer case. If you had to do it again, would you repair it in the truck, or remove the case and do it on a bench. I had not considered leaving the case installed until
I read your post. Thanks.

 

[Oldworldtenacity]

I got my 923 in December, and when I drive it, it is so loud. I thought it was nature of the beast. I would have to wear earplugs. This thing shook, shimmied, banged down the road. I checked all ujoints, ok. I noticed that the output flange on the front driveshaft was leaking really bad. I removed the front driveshaft and noticed that the output flange has a ton of play causing the seal to leak. At the time I couldn't get the nut off the flange with my 1/2 inch impact. I haven't had time to put my 3/4 on it yet. Is there a way to tighten or shim this? Do I replace a bearing? Replace transfer case? I will attach a video on here. I drove the truck home from work(40miles) and it drove like a dream with the front driveshaft out. It had minimal tire noise, but that was it! It drives like I always thought it should sound. I would rather not put a transfer case in it. What do you guys think?
https://vimeo.com/161219441

So, I think I might have the same problem as you. Can you verify if this is what your truck is doing. Mine will get worse with the truck warms up. It takes about ten mins of driving around before it will start doing and it gets worse with time and the more you drive it.

I posted 3 videos today and the audio is pretty good. The input I've had thus far is that it is the transfer case because I had my shafts inspected at a drive line shop and they said they are in excellent shape.

Opinions after watching the videos below anyone?


https://www.youtube.com/watch?v=yZEP5p6duek

https://www.youtube.com/watch?v=kjj7Ly0l5zE

https://www.youtube.com/watch?v=WwWaJhUOA4U

 

[Monkeyboyarmy]

Monkeyboyarmy-

I'll be replacing the same bushing on my transfer case. If you had to do it again, would you repair it in the truck, or remove the case and do it on a bench. I had not considered leaving the case installed until
I read your post. Thanks.

I was lucky to get all of thrcshafts to line up and to get it sealed up properly. I had no way if dropping the whole thing at the time so I figured it was worth a shot. Now I have a wrecker and would Opt to drop the whole thing. I checked with several major vendors about availability of the bushing with no luck. I ended up making my own.

 

[74M35A2]

This one hits home a little for me because I have a front end vibration at speeds > 40mph. The vibration goes away if I engage the front drive. So, I think the spline joint is worn in my front driveshaft. I crawled under, and I could not wiggle my transfer case front shaft PTO flange, but I can somewhat wiggle the spline joint of the front shaft. I bought a used front shaft that has the carrier bearing on it, along with the carrier bearing mount plate, it simply bolts to the cross member. I read somewhere that this was removed on later units, yet should have been retained. After reading this, I am now hoping that the front shaft length is compatible with my 925A2.