Idle Vibration Normal?

[rodent]

Still new to this M1008 truck and I'm trying to find out how much vibration is normal in these trucks at idle. The dash rattles and other parts rattle on the inside with the truck in drive at a stop. Also the bed rattles and you can clearly hear it outside the truck.

Is this a common symptom of a bad harmonic balancer or could it be something else something else? I may check the flexplate too and motor mounts too.

 

[porkysplace]

Still new to this M1008 truck and I'm trying to find out how much vibration is normal in these trucks at idle. The dash rattles and other parts rattle on the inside with the truck in drive at a stop. Also the bed rattles and you can clearly hear it outside the truck.

Is this a common symptom of a bad harmonic balancer or could it be something else something else? I may check the flexplate too and motor mounts too.

The harmonic balancers are know to be a problem on these , 30 year old rubber binding them together.

 

[rodent]

The harmonic balancers are know to be a problem on these , 30 year old rubber binding them together.

That was my thought too. I know they tend to go out and could cause damage to the engine.

Thoughts on a decent brand to get? Or are they are all the same? I know Fluidampr is the best but $400 is a little much to spend. I'll try that first since its easy to swap out.

 

[porkysplace]

It is just part of maintenance.
I would go with AC Delco
Replaced harmonic balancer

plenty of reading hear.
https://www.google.com/search?ei=xy...6275...33i21k1j33i160k1j35i39k1.0.iru9XjO1Zd4

 

[rodent]

Thanks! Just wasn't sure if vibration was a symptom of a bad one or not. Either way it needs to be replaced from age.

 

[TGP (IL)]

Check your motor mounts especially the right side.
I'm sure you'll find there shot and the engine brackets are touching the cross member.
That sets up all kinds of noises and vibrations.
Tom

 

[ken]

If the rubber on your balancer has ANY CRACKS then replace it!!! Don't take a chance. I have broken a crankshaft this way.

 

[rodent]

Check your motor mounts especially the right side.
I'm sure you'll find there shot and the engine brackets are touching the cross member.
That sets up all kinds of noises and vibrations.
Tom

Thanks Tom. Will look there as well. Hopefully they are not too hard to get to. I do have an engine hoist that can lift up the engine a couple inches.

If the rubber on your balancer has ANY CRACKS then replace it!!! Don't take a chance. I have broken a crankshaft this way.

Ordering one tonight regardless. Thanks!

 

[Barrman]

If all the parts mentioned above check out ok. It could just be as simple as your idle speed. My first M1009 had a terrible harmonic that made everything shake and buzz after I had driven at highway speeds for more than 20 miles. I figured out a way to check idle speed and just a 50 rpm difference made it all better.

 

[ken]

Thanks Tom. Will look there as well. Hopefully they are not too hard to get to. I do have an engine hoist that can lift up the engine a couple inches.

You will not need to lift the engine to replace the balancer. Just remove the fan, shroud and pulley. it comes off easy with a good puler

 

[cucvrus]

Motor mount on left side will allow the stud of the exhaust manifold at the oil dipstick to chew into the upper frame flange. May I suggest Energy Suspension motor mounts? And the right side of the right will sink and rest on the fuel feed line. Causing a possible minor fuel leak and allow the system to drop fuel and make for hard starting. Just a thought. I changed my motor mounts and put new ones from NAPA in place. 1 trip to Rausch Creek and the mounts were sunk. I think they were old stock and the rubber disintegrated on a hard pull at the power lines. Good Luck. Stay warm. Do 1 side at a time and a piece of wood and bottle jack work fine.

 

[BradL84D30M1008]

I replaced my motor mounts with ORD competition motor mounts, and also replaced harmonic balancer, transmission cross-member and adapter between transmission and transfer case......truck still has all kinds of rattles and buzzes/vibrations......what I have noticed though is that depending on what kind of terrain I've put the truck through in 4WD, the severity of the rattles/buzzes/vibrations may change and/or migrate to different areas of the truck......bottom line my '84 M1028 is a beast offroad, and I chalk up rattles/buzzes/vibrations to 30+ year old suspension/frame technology.......doesn't bother me.

 

[stonewalljac]

Agree on engine mounts and Damper problems. My M1009 is as smooth as an air motor.

 

[cucvrus]

I replaced my motor mounts with ORD competition motor mounts, and also replaced harmonic balancer, transmission cross-member and adapter between transmission and transfer case......truck still has all kinds of rattles and buzzes/vibrations......what I have noticed though is that depending on what kind of terrain I've put the truck through in 4WD, the severity of the rattles/buzzes/vibrations may change and/or migrate to different areas of the truck......bottom line my '84 M1028 is a beast offroad, and I chalk up rattles/buzzes/vibrations to 30+ year old suspension/frame technology.......doesn't bother me.

I am surprised you still have teeth in your head. They are solid steel on steel motor mounts from looking at the picture. Why are you afraid all 135 HP in the CUCV are going to flop the engine over if you accelerate too fast? That truck has enough rattles it don't need solid motor mounts. Now I would be afraid of breaking things. You want the flex with at least urethane mounts. Have a great day. Vibration free I hope.
http://www.offroaddesign.com/catalog/motormounts.htm

 

[Ilikemtb999]

I am surprised you still have teeth in your head. They are solid steel on steel motor mounts from looking at the picture. Why are you afraid all 135 HP in the CUCV are going to flop the engine over if you accelerate too fast? That truck has enough rattles it don't need solid motor mounts. Now I would be afraid of breaking things. You want the flex with at least urethane mounts. Have a great day. Vibration free I hope.
http://www.offroaddesign.com/catalog/motormounts.htm

They have urethane bushings in the mounts. They’re in the pictures in the link you posted.

 

[rodent]

They do transmit more vibration than the factory mount. I'd rather use the stock rubber clam shell engine mounts or even do the energy bushings inside the clam shells. Held fine on a modified 496 BBC.

 

[rodent]

Update- Replaced motor mounds but still have vibration. Next up is harmonic balancer.

 

[Barrman]

Do the timing cover front seal while you are at it. Also, get the balancer puller kit with the 16x 1.5mm thread main shaft. Then you can use it as a balancer installer too.

 

[rodent]

Do the timing cover front seal while you are at it. Also, get the balancer puller kit with the 16x 1.5mm thread main shaft. Then you can use it as a balancer installer too.

Thanks! Yeah I was just looking for a bolt that size to install it with my HB tools. Also need to verify pulley is good. Hopefully Dorman HB is ok to use. Ordered the seal 2 days ago, need to go get it.

Still have a vibration in drive at a stop. Need to look at trans mounts too.

 

[the skull]

Check to make sure your power steering pump is tight. Mine was loose, sounded terrible at idle. Quiet just off idle