RPMs while in D at a stop

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scwill

scwill

Joined
Jan 9, 2017
Threads
52
Messages
515
Location
Central Texas
What RPMs should i be seeing? RPMs while in park and while in Drive?

Im holding right 600 while in D, about 700 in park.

At a stop light, while im still in D, i have what is best described as an increased humming sound in the cab, it can be annoying, here lately i just throw it into neutral until the light turns.

Any thoughts?

Thankya.
 
Sounds like your interior trim really, really likes to be vibrated at 600 RPM...

Have someone go around the interior pressing in various places until you find where it's coming from. Then shove them behind it. :)
 
Ayune said:
Sounds like your interior trim really, really likes to be vibrated at 600 RPM...

Have someone go around the interior pressing in various places until you find where it's coming from. Then shove them behind it. :)
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Didnt think of that. Will look into it. Its really odd. I thought it might be the engine cover, i pulled it and no change. Then i started thinking maybe i need to change my spark plugs, but the engine to me feels really healthy.
 
I have it but it's the plastic engine cover. The foam blocks have rotted away so it's free to vibrate harmonically when the engine reaches that frequency when stopped in Drive. It's more of a fluttering/clanky sound but it's damned annoying and makes my truck sound like it's falling apart.

Come spring I'm going to find some replacement foam or rubber I can use to isolate it...

In regards to the interior, I know the upper part of the interior of the hatch likes to vibrate so check for broken clips... I resealed my third brake light and didn't notice one of the clips was missing and it drove me insane until I isolated it to that body panel.
 
scwill said:
What RPMs should i be seeing? RPMs while in park and while in Drive?

Im holding right 600 while in D, about 700 in park.

At a stop light, while im still in D, i have what is best described as an increased humming sound in the cab, it can be annoying, here lately i just throw it into neutral until the light turns.

Any thoughts?

Thankya.
Click to expand...

I get a similar sound, coming from somewhere in back... but once I put it in park to go look, the rpm's change and it stops. MAJOR PITA. I am going to go try what @landylover21 suggested
 
TXSunDevil said:
I have the same issue.
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Glad its not just me. Its my number 1 irritating issue with my rig. Im at a loss, gonna check interior trim but my guess is nothing is really wrong, its just another quirk to add to my list. I think its vibration from engine through the guts of the truck. Some might have it, some might not. Some might notice it easier than others as well.
 
One other thing to keep in mind: if your skid plates (if you can call them that) are missing any bolts or are loose, they too will resonate in harmony with certain engine frequencies. I had a problem a few years ago where I accidentally sheared the center bolt off the metal skid plate and there was just enough play to make it rattle at certain engine idle and load speeds.

Drilled and retapped and tightened it up once more. No more rattle.

Also, check your cat heat shields while you're under there!
 
I also have the problem. It's not a rattling sound like from a heat shield but more of a droning, low frequency sound.
 
I have the same drone noise. Come spring I’ll get under there to look around. Other than that there are no issues and runs strong and smooth.
 
Me too. Figured mine was an idler bearing or some sort of bearing under the hood that was on its last leg. The sound/vinration Goes away when in neutral.

You can easily feel it and i suppose eventually whatever it is will finally give out.
 
Even though this has been discussed a lot already, here’s my thoughts. This issue is mainly attributed to the rigidity of the LC ladder frame and body. While being even stronger than the 80 and many other vehicles on the road, this extra strength I believe creates resonance issues. The vibration is felt in gear while stopped because the transmission has a load applied to it. When the transmission is free spinning (in neutral or park), all the extra forces have a place to dissipate. As our vehicles age, their rubber starts to harden and crack or give way, leaving little to no proper material for vibration dampening.

I believe that our issues are not simply one item, but a collection of problems that manifests itself over time. Engine running at a lower RPM due to dirty throttle body, MAF, etc. and bushings not properly doing their job.

Some things I have done that have improved vibration:
-removed engine cover
-changed spark plugs and bad coils
-clean throttle body
-changed all fluids to synthetic
-cat shields

These helped, but I still have some vibration and I feel it can be gone away with. My plans for dealing with it are to:
-replace engine and transmission mounts (1 engine mount is failing for sure)
-replace all coil packs with OE denso
-Add sound deadening material to the body to help deal with general resonance issues.
 
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DirtDawg said:
Even though this has been discussed a lot already, here’s my thoughts. This issue is mainly attributed to the rigidity of the LC ladder frame and body. While being even stronger than the 80 and many other vehicles on the road, this extra strength I believe creates resonance issues. The vibration is felt in gear while stopped because the transmission has a load applied to it. When the transmission is free spinning (in neutral or park), all the extra forces have a place to dissipate. As our vehicles age, their rubber starts to harden and crack or give way, leaving little to no proper material for vibration dampening.

I believe that our issues are not simply one item, but a collection of problems that manifests itself over time. Engine running at a lower RPM due to dirty throttle body, MAF, etc. and bushings not properly doing their job.

Some things I have done that have improved vibration:
-removed engine cover
-changed spark plugs and bad coils
-clean throttle body
-changed all fluids to synthetic

These helped, but I still have some vibration and I feel it can be gone away with. My plans for dealing with it are to:
-replace engine and transmission mounts (1 engine mount is failing for sure)
-replace all coil packs with OE denso
-Add sound deadening material to the body to help deal with general resonance issues.
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Couldnt agree more dude. Well said.
 
allan man said:
I vote rubber engine mounts /transmission and exhaust.
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I will add that I had my muffler swapped out and that helped a little bit. I would like to replace all my exhaust hangers at some point, but with the steep price of OEM, I will probably just come up with something on my own.

My vibes are almost all gone.
 
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I get noises if something is resting on the transfer case lever, or if a pop can in the cup holder is not full and is touching the sides of the cup holder, it will vibrate and make noise.

For you it could also be a heat shield that is loose.
 
I still get some rattling, but one major source was silenced by making sure the Hi/N/Low nob on the center diff lever was as tight as it could be.
 
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