Engine/Transmission (1998.5 - 2002) VP44 and 2K rpm drone

[Gary - K7GLD]

"Does yours occur when pulling a trailer or solo? "



MUCH more pronounced when towing our fiver, and under a good load - but can be reproduced driving unloaded under heavy throttle - just not as noticeable - sounds to me exactly like a vibrating baffle plate inside the muffler...

 

[tmccormick]

So far it's been a solo thing but like I said in the above post it won't be long untill it does see a load.



Just for the record the truck is completly stock.

 

[rfletcher10]

Garry kj6q sounds like a call sign mine is kg6jrt



my drown gets louder with more load the steeler said it is the overdive but I don't think so. I am on a trip right now and I tryed driveing with out overdrive and was able to get it to drone at 1900- 2000 rpm. While I was in overdrive and drive around 80 mph I hear and feel a slight vibration kinda like a driveshaft out of balance. The dealer called me just before I departed on my trip and said they have a rebuilt transmission for me so when I get back I will let them put it in under warrinty. So we will see if thay are right.



robbie fletcher

2001 2500 auto

 

[sag2]

A quick way to check for exhaust drone is to wedge wood blocks between the exhaust and the frame to put it in a bind. If the noise/vibration changes, you are on the right track. A tie down at the outlet can also be used to put some pressure on the exhaust.

 

[rfletcher10]

Sag2

Great tip I will try it before I get the transmission replaced.

 

[Lsfarm]

Pipe resonace or vibration

What you guys are hearing is the exhaust pipe itself vibrating in concert with the engine vibrations at those certain rpm's.



The reason it can just develope is that the rubber mounts get softer over time, and the weather is warming up. These combined makes the 'hold' on the exhaust system weaker and allows it to whip or vibrate easier .



The engine vibration is greater when under load, so the pipe also vibrates more when you are towing or under load.

The suggestion to block the system and see if it changes is a very good idea.



Do a search for Drone or Dreaded Drone and sit down with a beverage for a long read, this is a common problem.



The best way to 'fix' it is to change the mass or resonance frequency of the pipes. Clamping on angle iron has been done with some success.



I changed the system to a very heavy pipe [1/8" wall] and this eliminated the drone. [in my truck at least]



Our engine makes a different sound, I like to call it a groan of power, it is the combination of intake noise, exhaust noise [NOT exhaust pipe] and the engine straining under load. This sound is not annoying anywhere near as much as the 'Dreaded Drone'



Hope this helps



Greg L. The Noise Nazi

 

[John]

The way I cured my 1,900-2,100 RPM drone (started just after I installed my Banks 4" dia. stainless steel exhaust system), was with Rip Rook's advice and installation assistance. Although I insisted on the replacement of my Banks Dynaflow stainless steel muffler with a slightly longer MagnaFlow stainless steel counterpart, I also added a 14" long (body length) MagnaFlow stainless steel muffler approx. 2' upstream of the main muffler (the downstream end of the "main" muffler terminating just ahead of the rear axle)... the division of the long run between the turbo and the "main" muffler totally eliminated my drone!

 

[tmccormick]

Lsfarm, sounds like a good possibility as to what you are saying.



Yea, just showed up one day out of the blue and hasn't stopped.



The thing that gets me is the vibration. If it's the exhaust will it vibrate the go pedal and floor board?

 

[Lsfarm]

Yep, sure will

Have you ever noticed the door to your kid's room rattling and vibrating to the loud music they are playing in thier room? [or any similar situation]



Sound is energy transmitted though the air, and any surface will try to vibrate in concert with it. So yes you will feel loud noises as a vibration through the floorboards of the cab.



Greg L. The Noise Nazi

 

[tmccormick]

OK, you got me on that one



Lets for grins say I take it into the dealer and explain to them what it is doing, what do ypu think they would do to remedy the problem if anything?

 

[Lsfarm]

Dealer?

I kind of doubt it, unless you can take the service writer out and demonstrate just how obnoxious it is, then maybe they will try to fix it.

But considering the amount of effort some of the TDR members have used to try to minimize the drone, I can't see the average parts-changer at a dealer doing you much good.

The problem is that there is nothing actually wrong with the exhaust system, it is just vibrating with the engine. You can't SEE anything wrong. I suppose it is worth a try.

I would find a stretch of road on which you know you can duplicate the drone at it's worst and take the service writer for a ride, and keep your fingers crossed.

What they would actually do to fix it? I don't know; I guess they might just replace the system or the hangers.



Good Luck, Greg L The Noise Nazi

 

[John Berger]

I had that drone also, same RPM level as most; 1800-2100 rpm, especially when towing. Putting on a 4 inch exhaust system seems to have minimized it. I don't think it's anything to worry about.

 

[tmccormick]

One question though... I always thought you got the drone after going to 4-5" exhaust not the stock one



I will try to wedge or some how change the way the exhaust hangs and see if I get any change. I really really want to believe that is all it is but dang it everytime I get in and drive it something comes over me and says thats not what I'm hearing/feeling but again I may be wrong.



This may be going out on a limb but by chance is there any member that is in the Denver area that has had this problem that may be willing to drive my truck and tell me what they think?



To me and I'm sure most others the dealer is the last place I want my truck to be.



Thanks for all your responces, tmccormick.

 

[rfletcher10]

HI EVERY ONE I GOT MY TRUCK BACK FROM THE DEALER WITH A REBUILD transmission AND THE DRONE IS GONE. THEY SAID THAT THE OVERDRIVE WAS THE PROBLEM. I AM NOT SHURE IT WAS THE REAL PROBLEM I STILL THINK IT WAS AN EXHUST PIPE HANGER THAT COMES FROM THE transmission MOUNT. IT MIGHT OF BEEN INSTALED WRONG OR SOMETHING BUT WHAT EVER IT WAS THE DRONE IS GONE

ROBBIE