Shuttering sound/feeling

[thegreydog]

This has now happened three times now. I fire up the truck, let it warm up. Drive about a mile down the road and I get a shuttering sound/ shaky feeling. The truck still goes but not full power. Almost like a shaft had came loose or an engine brake. When it happens, gas, brakes or neutral makes no difference. The only thing you can do is slow down and let it finish. Once it does it, I have not had it happen again on same trip. Sorry if that's vague, but I'm not sure how to explain. Hopefully someone knowledgeable knows.

 

[doghead]

What model truck?

 

[thegreydog]

1985 M923A1. Sorry, on cell, I thought I had it in signature.

 

[thegreydog]

It seems to happen every time I drive now. Whatever the noise/shutter happens a couple of minutes after started and a couple miles down the road. I put the truck in neutral and almost stop. The shuddering stops and I continue on like nothing happened

 

[162tcat]

I occasionally have a similar issue on one of my trucks. I think I have a cylinder that doesn't fire under certain conditions. I'm going to adjust all of the injectors and see if that solves it.

 

[Floridianson]

I occasionally have a similar issue on one of my trucks. I think I have a cylinder that doesn't fire under certain conditions. I'm going to adjust all of the injectors and see if that solves it.

I would run the Cummins Flush and Adjust through the system before you adjust the injectors.

Back to Graydog can you tell if it is transfer case or trans.

 

[thegreydog]

You can't tell. You can feel it in the steering wheel, the truck shudders/vibrates... It does sound like it is a rolling noise. I have tried tapping brakes, down shifting, and neutral while traveling. Nothing helps, but coming to an almost complete stop, then it goes away and does not come back until you crank up and drive about 1-3 miles. This is driving straight down road, medium push on accelerator, no brakes, no bumps, just asphalt.

 

[Suprman]

Maybe binding u-joint or wheel bearing did you check the front boots

 

[Floridianson]

Do you have 6 truck jack stands? I would put the truck on jack stands and see if you can find the shutter while its in gear running. I don't like to say these words but bad bearing in!!!!!!!!

 

[Rifleman]

Now this is apples and oranges, but i had a car with an automatic transmission that had the same type of shutter problem. The car would only shutter while it was moving under load, while it was at a stand still no shutter at all. What it turned out to be was the torque converter coming apart inside. Lets hope that's not the case with your truck, but you could always pull the remote trans filter, cut it open and see if your trans is making any metal.

 

[73m819]

I think the op has a small air leak that is becoming a big leak, the engine tries to run out fuel till the fuel catches up, at shut down the fuel wants to go back to the tank due to the air leak, being a small leak, only a bit of fuel leaks back, the gear pump pulls more then the leak so it catches up the fuel. Look at the top of the fuel filter, make sure the flat washer if flat and set right in the recess,

 

[thegreydog]

I am in the process of switching from 10w in transmission to Dex. Allison recommended I flush and fill, drive 500 miles and then drain and change filters. Another hundred miles and I'll be done. It is a rotational shudder almost like in wheels or drive train. The part I don't understand, it does it after it is ran about two miles then never again until I shutdown for a bit, crank and go again.

 

[thegreydog]

I finally found a mechanic that seems to know the truck. I'm taking it in next week. The shudder has started happening more on short trips. In ten miles the other day it happened three times. In testing, it happens on smooth or bumps, temperature doesn't seem to make a difference, speed made no changes... The only thing that stops the problem is to come to a complete stop. Very confused

 

[Floridianson]

I found I had a bad bearing on a front axle once and it caused the race to break loose and spin. Good luck hope it's low buck