2011 872G Has a violation shake. Chooses random times to go into what feels like axle wrap. Dealer mechanic Rebuilt diff. Still did it with tandoms removed. Rebuilt transmission, still does it. Replaced bushing play in articulation Rams, still does it. Replaced motor mounts still does it. Only 2000hrs on Rebuilt drop in engine. Measured Driveline up and down, has 3% slope like the other machines. Lucent 04 motor mounts and aligned Driveline, only 1/16" out. Still does it. Measured frame. Frame is straight and in lighn. Shake is so violent engine and transmission move side to side about an inch, what feels like some sort of axle wrap at random times going down the highway Vehicles following will back right off as the Ripper slams up and down and the muffler shakes from side to side Any one have any other ideas?
Are you saying it does this even with the tandems removed or did I misread that?
Yes it does it even with both tandems removed blocked up in the air. We also put a new driveline on. We really thought the 4 new motor mounts would fix it.
It shakes side to side with the wheels removed... Sounds like it hits a resonant frequency that amplifies the shake of the rotating engine mass. Does changing the engine RPM make a difference? Check the harmonic damper on the crankshaft. That's the part that's supposed to absorb the shake from the engine. Next suggestion is to bolt a heavy mass to the engine... changing the resonant frequency.
Yeah, I'd also say take a good look at and maybe remove the fan... Seen distorted fans really vibrate machines.
Coupler between the engine flywheel and the transmission changed? Did you try it with the driveline removed?
That absorption plate between the engine and transmission we went through all the Springs are good however we did not try it with the drive line off we will try that. Thank you! I will let you know the results
Wish I had words of wisdom. With that said, my bet is something internal on the engine. Hopefully the OP will post the search and solution.
I really suspect something that is rotating at or near engine speed. Flywheel is also a possibility. Torque converter another.
Truck owner asked me one time to look at his truck, cabover Pete if I recall correctly, silver 92 Detroit in it. Said it had a weird vibration that came and went. They had the cab tipped up and the engine running, he tells his driver to goose the throttle a bit... once, twice, I saw the problem and hollered to shut it down. Only thing holding the crank pulleys and dampener on was the tension of the belts, it was walking back and forth a couple inches at least and the keyway was an inch wide, lol. Whoops.
Does it smoke when this is happening? Just wondering if it could be turbo surge. This new stuff with EGR is always on the edge of that.
Really appreciate all the reviews. We can not get up to speed with the driveline off or the transmission yoke will come flying out. Thanks for the advice Monday morning we are going to measure the front engine dampner while running. No smoke. Engine sounds strong. Doesn't power down chooses complete random times to go into self destruct mode. Seems worse in higher gears or under load. When we find out what is causing this I will definitely post the solution. Thanks
I see I skipped a question. RPM doesn't make a difference. It won't do it if we Rev out the engine. It only does it in gear. We have 16 of these same machines on the road and seen just about every type of shake and break down possible. This one is an ugly one. The machine will be running top performance for a couple hours and then do a random Wicked Shake. We've spotted that the previous owner replace the bell housing between the engine and transmission for some reason. After we check the fan and the other recommendations posted we may investigate a little more to make sure that was the right bellhousing installed.
If it's got a new bellhousing, could it have something to do with the hydraulic pump drive? Be something when the pump is running wide open- like when the fan reverses?
I was reading this post...it dead ended...what was the problem?