Diesel vs gasser differences

[chrisbh17]

In an effort to try and combat some of the buzzing feeling during acceleration, I was looking at various mass dampeners available for our trucks.

Turns out the diesel gets a bunch of stuff our gasser doesnt. For example: a harmonic damper attached to the axle/engine mount, a mass damper attached to the steering wheel and a harmonic damper attached to the transfer case.

The fact my vibration gets worse when 4-Auto is engaged makes me think it might have something to do with the 3 driveline pieces mounting together (engine, differential, axle), so Im really curious if any of the above dampers might help the issue any.

Does anyone have any idea if the diesel dampers/weights might help any? I know its a tough ask (most people probably havent even noticed them there) but any help you could provide would be appreciated.

Thanks.

 

[Mr.AK902]

In an effort to try and combat some of the buzzing feeling during acceleration, I was looking at various mass dampeners available for our trucks.

Turns out the diesel gets a bunch of stuff our gasser doesnt. For example: a harmonic damper attached to the axle/engine mount, a mass damper attached to the steering wheel and a harmonic damper attached to the transfer case.

The fact my vibration gets worse when 4-Auto is engaged makes me think it might have something to do with the 3 driveline pieces mounting together (engine, differential, axle), so Im really curious if any of the above dampers might help the issue any.

Does anyone have any idea if the diesel dampers/weights might help any? I know its a tough ask (most people probably havent even noticed them there) but any help you could provide would be appreciated.

Thanks.

They would help if it was possible, but you won't e able to mount the dampness produced for the HD trucks on your half ton.

 

[chrisbh17]

They would help if it was possible, but you won't e able to mount the dampness produced for the HD trucks on your half ton.

Sorry I didnt state it....they are made for the 1500 and Ecodiesel.

Axle damper - 68196766AA Its called an axle damper but seems to mount on 2 of the bolts where the engine and axle mount together. Best pic Ive seen of it installed is in the instructions for various aftermarket air suspensions.

Steering wheel damper - 5057613AH (I actually already bought a used one, have not installed it, confirmed it does fit though)

Xfer case damper (requires a different rear xfer case half, though) - 68232310AA

 

[Scottly]

I'm confused. It's truck, not a Rolls Royce. If it vibrates THAT bad, maybe something else is wrong with it.

 

[FXCLM5]

i did not know the ecod 1500 has 3 extra dampeners to help with sound deadening, interesting,

i can tell you my 14 hemi and 17 ecod had roughly the same cabin noise driving around town and cruising 70-75, but when you step on it the hemi sounds like 500x louder then the tiny diesel.

 

[chrisbh17]

Its not a vibration like the steering wheel moving back and forth, etc. Its a buzzing type "vibration", like if you put a cellphone on the back of the gas pedal and called it. Feel it in the gas pedal, floorboards and steering wheel. but it is not "death wobble" or "wheel/tire out of balance" or "rear driveshaft/u-joint wobble".

I know its a truck and not a Rolls, but its literally the only thing that bothers me about my truck. And oddly enough every other one I test drove did the same thing to some extent, BUT my 17 year old Frontier NEVER did. So, why should me new (at the time, now 1 year old) RAM do it?

The fact it seems worse/more pronounced with the truck in 4-Auto makes me think its something with the front axle, differential, or how they all mount together (harmonic resonance). Add a weight here and there and it might break the resonance.

@FXCLM5 you can see the axle weight if you look at where the axle comes together near the engine mount. The transfer case weight looks like a puck on the front engine side of the case. Steering wheel weight is invisible.

I know some of these weights are "tuned" so they might be unique to whatever frequencies the diesel causes, but Im still curious enough to possibly try at least the axle mount weight.

 

[FXCLM5]

i would just put sound deadening in,

check out some of the guys build threads in the audio section, they remove the entire interior and dyno line it, it literally blocks every noise possible lol, people who do it just in the doors say its a night and day difference, then again full interior is night and day difference from just doors.

 

[Fitz-0518]

That is not going to help with his issue. Mild out of balance vibration. Chris my neighbor has a 2018 GMC 2500 diesel. Has the same issue. The dealer has had him drive others and he notices the same but not as pronounced. I suspect something is out of balance in that front end. If it was me,,,I would be suspect of the drive shafts. I would have to take them out and take them to my drive line shop. Have them spun and balance. But,,I am OC. Fitz

 

[huntergreen]

Chris, are you leveled ?

 

[chrisbh17]

Truck is stock, does have "raised ride height" option from factory, I think thats just taller springs (and 99% of the RAMs seem to have it anyway)

Something I noticed today...it is most obvious in 4-auto, but as I was driving if I maintained steady state acceleration, from below 2K RPM to above 2K RPM, you could almost "hear" a louder vibration or rubbing just "turn on" at 2K RPM. Then it slowly faded away by 2300RPM. Under 2000RPM there was nothing. Its really strange, almost like a quiet rubbing noise and the corresponding feel you would get through the steering wheel and floor.

Also note this is with MDS disabled, I basically lock into whatever gear I need to be able to hold the engine around 2K RPM so I can re-create the issue.

 

[Big Terry]

Only thing I hear in my cummins, is my cummins. I am personally not prone to hearing random noises; I'm a truck driver and somewhat hard of hearing, so no matter what noises my personal truck makes it is still quiet as a morgue compared to the work trucks.

 

[chrisbh17]

Yeah this isnt as much a noise as it is a buzzing vibration you feel in your feet and hands. Its an annoyance, at least so far, but I dont know if its something major that is causing it.

Driven several other Hemi based RAMs and they did it to some extent. Mine feels worse (maybe because its mine?), dealers say its normal because they found other trucks on the lot that do it.

But the fact it gets worse in 4-Auto is what bothers me the most. Because A) my old truck never did it and B) worse in 4-Auto should be a clue to help figure out WTF it is but no dealer wants to bother.

 

[JPT]

Wonder if it is an out of balance front drive shaft. I'm not entirely familiar with the 44-44 and if the front shaft spins when in 2wd.

It may be cheaper/easier than dealing with the dealer to just bring it to a driveline shop.

 

[chrisbh17]

Wonder if it is an out of balance front drive shaft. I'm not entirely familiar with the 44-44 and if the front shaft spins when in 2wd.

It may be cheaper/easier than dealing with the dealer to just bring it to a driveline shop.

Driveshaft does spin in 2WD, but I pulled the driveshaft and drove it over the weekend, still had the buzz feeling. Im not 100% sure all of what that rules out, but it definitely was not the driveshaft itself (that would be too easy...)

Just trying to logic it out - all 4-Auto setting does is engage the axle actuator (a sleeve that connects the front right axle to the front differential....that part works the same as trucks with the 44-45). Without any rear-wheel-slip, there should technically be no torque coming from the transfer case.

The fact it gets worse with the axle actuator engaged but no torque coming from the transfer case, what does that mean?

It should be a clue but the dealers dont seem to care and I dont really know what it means.

 

[JPT]

axle shaft u-joint?

 

[Silver Goose]

Driveshaft does spin in 2WD, but I pulled the driveshaft and drove it over the weekend, still had the buzz feeling. Im not 100% sure all of what that rules out, but it definitely was not the driveshaft itself (that would be too easy...)

Just trying to logic it out - all 4-Auto setting does is engage the axle actuator (a sleeve that connects the front right axle to the front differential....that part works the same as trucks with the 44-45). Without any rear-wheel-slip, there should technically be no torque coming from the transfer case.

The fact it gets worse with the axle actuator engaged but no torque coming from the transfer case, what does that mean?

It should be a clue but the dealers dont seem to care and I dont really know what it means.

The vibration that you hear/feel is real, but until it is isolated a fix cannot be assigned. I would suggest to put the vehicle on a dyno and run it at different speeds
You may be able to isolate the area of the vibration and then dampen the vibes.
It is true many vehicles have dampeners located around or on the drive system.

The other plus by running the vehicle on the dyno is the fact that the drive shafts can be observed running under load.

Good Luck

Larry

 

[chrisbh17]

If I get it onto a dyno, how could I track down the vibration? I figured I needed to be under it which cant really happen while on a dyno.

I used a GoPro to get a couple videos of the front driveshaft and could tell it wasnt vibrating. I have not tried videoing the front axles, yet.

 

[huntergreen]

I am not sure you visually check a drive shaft for vibration. Have you you turned of MDS to see if that has any effect ?

 

[Rader]

Driveshaft does spin in 2WD, but I pulled the driveshaft and drove it over the weekend, still had the buzz feeling. Im not 100% sure all of what that rules out, but it definitely was not the driveshaft itself (that would be too easy...)

Just trying to logic it out - all 4-Auto setting does is engage the axle actuator (a sleeve that connects the front right axle to the front differential....that part works the same as trucks with the 44-45). Without any rear-wheel-slip, there should technically be no torque coming from the transfer case.

The fact it gets worse with the axle actuator engaged but no torque coming from the transfer case, what does that mean?

It should be a clue but the dealers dont seem to care and I don't really know what it means.

Something does not sound quite right. The reason for the front axle disconnect is to stop the ring pinion and front drive-line from spinning thus cutting drag = a fuel saving measure. My understanding is in 2WD the right axle is disconnected so when the left axle turns the torque takes the path of least resistance and that path is spinning the spider gears that weigh ounces and normally spin much easier than the combined drag and weight of ring gear, pinion, drive-line and front output on the T case.

I would guess that cold and especially in winter the thickened lube could cause enough parasitic drag between the side gears and carrier to spin the carrier but when the lube warms up the carrier should stop spinning. I think one preventive measure would be drain and fill the front diff with some quality synthetic with the lowest recommended viscosity.

 

[cbsmith]

Maybe it is the axle half shafts going from the hubs to the front diff? They would spin all the time though but only be engaged in the 4x4 modes.