X15 efficiency idle vibration

[newyorktruckah]

Hello everyone have a 2019 t800 with a Cummins x15 efficiency 500 with an Allison 4500rds. Truck idles at 600rpm from factory currently around 45k miles. I am having an issue with a heavy vibration at idle and when truck is put in neutral, drive or reverse. It’s shakes so bad you can’t make anything out in the mirrors, we do a lot of paving and my driver can’t make out hand signals from the spotters when slowly trying to reverse. I attached a slow mo video so you can see just how bad it shakes the ps reservoir. The engine mounts are good the trans has a type of transversal leaf spring which was missing the Teflon spacers which has been corrected. I am now starting to suspect that maybe the harmonic balancer has gone bad. Truck was parked for about a year in between it working started occasionally to shuffle around the yard. I am suspecting that the harmonic balanced might have internally become stuck or something to that effect. Let me know what you guys think could be the cause. No check engine lights or anything pulls great and smoothes out once comes off idle but will vibrate again if the engine lugs around 1450 rpm pulling a hill. Have a c15 in a 20 year old T800 and feels like a Mercedes v12 compared to this thing.
Thank you everyone!

Link to video

https://www.dropbox.com/s/9gtgqerr1gcdwe...6.MOV?dl=0

[Rawze]

That is kinda normal for those power steering reservoirs to shake like that... the mounting is horrible for them that have that style of bracket. if I owned it, I would have welded in a small piece of L brace to stop that crap.


as far as the mirrors shaking, tighten them up and its usually not a problem. I had to install hose-clamps on mine a long time ago where the cross-braces attach to stop mine.

the only real way to see if the crank shaft damper is bad, is to replace it and see if things get better.

[Hermjeji]

You could try bumping the idle speed to say 700? Used to do that on our cats all the time, everything was smooth at 700 onwards, and at 650 ish there was just a crap ton of resonance with everything in the cabs. I'm sure you can bump up the idle pretty easily through insite. Someone can chip in.

[SemiSweet]

Idle speed is easily adjusted with insite. I’ve got mine at 800rpm. Smooth idle at that setting plus better oil pressure if it does sit at idle for longer periods. Although, I always bump the idle up to at least 1000 when i need to let it run longer. I find every truck has a different rpm range where it will resonate and shake around

[newyorktruckah]

Great thank you gentlemen. The only problem with bumping the idle is that with the automatic it already really pushes at around 600 rpm. Even just holding it stopped at idle at a light requires significant brake application pressure. Anymore rpms would be excessive in this application although with a manual I could see it not really being a problem. With your foot off the brake it reverses at probably 13 mph lol! I have see a harmonic balancer from {aftermarket} do any of you guys have any experience with this product. This would be in addition to the dampener from what I am understanding at the moment.

I was also thinking could this be something in the tune of the engine with Cummins trying to advance timing too much to reduce emissions is this possible? With this being an efficiency series motor more geared to fuel economy. Could retarding injection timing at idle help remedy this is situation?Not sure if this is a worth while theory to pursue.

Thanks again everyone !

[Pete379]

I have a few x15s and they all idled just as you described when they were at set at 600 rpm.i bumped them to 720 and it smoothed out considerable

I am not familiar with the Allison transmission but I do have experience with x15s and Eaton automatics. As far as it pushing at idle with the automatic, With the Eaton ultra shift plus transmissions and there are settings in the transmission software that control this. I believe the setting was called urge to move and could be altered from the factory setting to stop the push you are describing. Do you know if the Allison has software settings that can be altered?

[newyorktruckah]

(01-21-2022 )Pete379 Wrote:  I have a few x15s and they all idled just as you described when they were at set at 600 rpm.i bumped them to 720 and it smoothed out considerable

I am not familiar with the Allison transmission but I do have experience with x15s and Eaton automatics. As far as it pushing at idle with the automatic, With the Eaton ultra shift plus transmissions and there are settings in the transmission software that control this. I believe the setting was called urge to move and could be altered from the factory setting to stop the push you are describing. Do you know if the Allison has software settings that can be altered?

Hello
Yes there are some settings of the Allison that can be altered like shift points, downshifting ect but as far as I know and I’m no expert the “grab” of the Allison is more of a Mechnical function of how aggressive the torque converter is and the viscosity of the oil since there is no clutch which I do not believe can be altered. Funny that you mention it I also have a t880 with an Eaton ultra shift 8ll and it is very smooth in comparison. I will try adding the harmonic balancer {after-market} as I don’t think that my dampener has failed with such low miles. I was hoping it would go in front of the dampener but it actually goes behind it lol sucks to have to pull both to install. It like 300 bucks and see what’s was. Thank you for the advice I will run through the Allison settings again to see if there might be anything I missed just in case.

[Rawze]

(01-21-2022 )newyorktruckah Wrote:  ... I will try adding the harmonic balancer {after-market} as I don’t think that my dampener has failed with such low miles. I was hoping it would go in front of the dampener but it actually goes behind it lol sucks
...

Your blowing smoke up your own arse there if you think that aftermarket garbage product is going to magically make all the vibration in the whole truck go away. - I have seen my share of ppl buy those things, put it on, and it did noting for them, especially if there was noting wrong with their balancer already.

[newyorktruckah]

(01-22-2022 )Rawze Wrote:  

(01-21-2022 )newyorktruckah Wrote:  ... I will try adding the harmonic balancer {after-market} as I don’t think that my dampener has failed with such low miles. I was hoping it would go in front of the dampener but it actually goes behind it lol sucks
...

Your blowing smoke up your own arse there if you think that aftermarket garbage product is going to magically make all the vibration in the whole truck go away. - I have seen my share of ppl buy those things, put it on, and it did noting for them, especially if there was noting wrong with their balancer already.

Ok well I am open for suggestions what do you propose? bumping idle is basically out due to the tranny pushing as it is. What other options are there? I don’t think all the vibrations are going to go away ... {rest of post removed by rawze}