droning

[matuva]

My truck start droning this week. I quickly looked at the exhaust line, everything appears to be nor$al. I will have a closer look at the downpipe when we'll get less heavy rains there.

Though, could it be worn motor mounts being involved?

Anyways, could it be considered as maintenance parts? and so having to be changed anyways?

In that case, what would be the best : stock with rubber bushings or aftermarket such as the ones from energy suspensions (polyurethane)?

Any opinion?

 

[Matt Bachand]

My truck start droning this week. I quickly looked at the exhaust line, everything appears to be nor$al. I will have a closer look at the downpipe when we'll get less heavy rains there.

Though, could it be worn motor mounts being involved?

Anyways, could it be considered as maintenance parts? and so having to be changed anyways?

In that case, what would be the best : stock with rubber bushings or aftermarket such as the ones from energy suspensions (polyurethane)?

Any opinion?

*I'm not sure what you mean by starting droning this week, but I think mine did the same thing.

I now have a 'surging' vibration feel, that has nothing to do with RPM, and nothing to do with WHEEL ROTATION, it seems to do it at diefferent speeds, mostly around 35-40, but it is like a slow throbbing that has nothing possibly to do with tire roation or driveshaft rotation. It's way to slow of a throb.

None the less I greased everything underneath and it seems to have changed it a little. Made it happen at high speeds, and less frequently. Is this the droning you are referreing to?

 

[Dan Hunter]

Are you talking about that gentle frequency phase shift sound that is noticeable when holding a constant speed? Take a look at your tire condition. Change the pressures a bit and see if that makes a difference.

 

[Brooklyn Tow]

If your original mounts are still in the truck, I would say they did there job.....on that note I would think OEM is your best bet.

But I don't think thats your droning issue.....Sounds like you're talking about an exhaust drone......Is it all RPM ranges or somewere in particuler? (Spell check)

 

[matuva]

Should be exhaut drone I think, but I haven't been able yet to locate the place where the line should touch.
That's pretty droning at around 1200~1400 rpms, a bit more quiet higher, and I can hear a slight "rooow-- roow--- roow" when I release the accelerator...

 

[Brooklyn Tow]

Maybe a hanger bearing.....Tranny mount......bad U joint?

Check your driveline, stranger things have happened.

 

[Acesneights1]

what size exhaust are you running ? Mine devloped a drone when I put the 4 inch on. Beeuive it or not a 5 inch tip can change that sound.

 

[matuva]

downpipe is a 3" flowmaster, and the line is 3" straight. I have this setup for several month, may be more than a year, can't remember.
This droning occured few days ago. I don't know if it is coincidence or not, but just before it happens, I got rid of the vacumm pump, and, as the belt was squealing, I changed the alternator and the tensioner, put a shorter belt (100") and realised that less 100 kms after, the belt is completely loosen so the tensioner doesn't even do its job. I have ordered a 99" belt.
Could a loosen belt induce droning somewhere?

 

[deejaaa]

My truck start droning this week. I quickly looked at the exhaust line, everything appears to be nor$al. I will have a closer look at the downpipe when we'll get less heavy rains there.

Though, could it be worn motor mounts being involved?

Anyways, could it be considered as maintenance parts? and so having to be changed anyways?

In that case, what would be the best : stock with rubber bushings or aftermarket such as the ones from energy suspensions (polyurethane)?

Any opinion?

carrier bearing would be my guess. these will transmit sounds all through the drivetrain system.
poly bushings are great for suspension parts(diesel/oil resistant) but are heck on the engine while all vibrations are transmitted to/from the engine to the frame and will tend to vibrate things loose.
the tensioner might also be the prob, does it spin freely or have any resistance?

 

[matuva]

Just a thought : it might be a coincidence, but as I post previously, I note that this happen few days after I change my serpentine.

Should it have stretched pulleys and may be damaged a few crank pulley or harmonic balancer?

How can you diagnose a bad crank pulley? Should it cause droning anyways---

 

[RadioMan]

How can you diagnose a bad crank pulley? Should it cause droning anyways---

Mine didn't drone, but it sure klunked when the engine changed speed, especially when it stopped.
It's easy to check - Pull the belt - grab the crank pulley and see if you can turn it by hand, either way. If it turns while the harmonic balancer stays stationary replace it. It's a sheave mounted with a rubber ring (basically). The rubber sometimes just quits being attached.

 

[matuva]

OK, I found the culprit : engine mount on the driver side.
The pic is not very good, but you can see what the arrow is pointing, that's the grey colour of fresh teared
of rubber of the bushing.

I'm not rude with my truck, so, I wonder how comes this mount has broke like that--- :sosp:

Anyways, just time to buy a new engine mount for driver side, and my frien mechanic will fix that for me.
He said this will be a PITA :mad2:

BTW, any knows the part # for the driver side mount, the all setup, not the bushing only?

 

[Schwind]

Drivers side mount receives a lot of torque pull.

factory mount# from sticky

Motor Mounts OEM - 15659675

 

[matuva]

Thanks for the part # :thumbsup:

Yup, torque, that's what I bet too.
Hope the mounts will afford the GL4 associated to the new A-team turbo--- :sifone: