M1009 Vibration at Idle

[tgtaylor64]

This has me stumped! My M1009 is a very smooth riding CUCV, except at idle. At idle is shakes. I thought it may be bad motor mounts. The engine seems to vibrate more than it should at idle and more than my other M1009. Mounts seem ok visually. I noted that my transfer case mounts were very squshy so I changed them out thinking that it would make a huge difference. No real noticable difference was made! It seems to be a rough idle and I have added gallons of Seafoam but nothing has helped so far. At any speed above idle, it runs great; no vibration and plenty of smooth power. Any ideas?

 

[dependable]

Maybe check flex plate for loose bolts or a crack. Both have been known to happen.

 

[doghead]

Is your idle too low?

 

[SpecWarSquid]

Mine was doing something like this for the past week or so. Lift the hood and the engine was making a horrible noise on top of the Diesel clatter. Turn outthe air filter housing was loose. The nuts had backed off enough to allow the housing to resonate at idle. Tightened them up and good to go. Noise went away. I like easy fixes as they tend to be rare.

HTH

 

[Sharecropper]

Sounds like a bad harmonic balancer.

 

[Cucvnut]

whos knows take it to a mechanic!

 

[wayne pick]

I agree with Sharecropper. A harmonic balancer can be had for less than $100.00. I would also stop driving it untill you find out exactly what is causing the vibration. If the balancer fails, the crankshaft will break, end of story. Your balancer is almost 30 yrs old, replace it. Sounds crazy, but check the power steering pump. The bracket is known to break in two places and transmit vibration and make a terrible noise. If the engine itself is jumping around like it's about to remove itself from the vehicle, it's more than likely the balancer.

 

[tgtaylor64]

I upped the idle a bit and it calms down!

 

[Sharecropper]

I suggest you check the harmonic balancer anyway. I am installing a new Fluidampr on my M1028 today.

 

[tgtaylor64]

Please let me know how the replacement goes.

 

[Sharecropper]

Just got my new Fluidampr on, and the engine is a lot smoother indeed. I had slight vibration before, however I attributed it to my tires. Now I know that it was not my tires, but instead that 27-year-old harmonic balancer.

Hope this helps.