Heavy shake/hop

crookedTRanspo · Mar 20, 2025

This post will be long and detailed

Truck:
2012 freightliner Coronado glider
12.7 S60 Detroit 10 speed 3.36 Rears
980,000 miles
Front Steertek air ride suspension
Rear airliner single leaf air suspension

bought the truck 5 months ago/40,000 miles since purchase
-previous owner mentioned driveshaft fell of truck and was replaced
-month later power divider over heated and was replaced with a Reman DS404

before I even hit the road I replaced the cab mounts, shocks, air bags and torsion bar plus a u joint at the trans yoke
Plus 2 new continental steers
New drums and shoes
New steer shocks
Front end was tight and in great shape

The issue:
Truck has a heavy shake/shudder/
First starts around 40 mph
Doesn’t matter which gear or rpm the truck hops every second or so
43-60 no issue
64-68mph it’s worse and worse the faster I go
It’s like a wheel is literally hopping
Very heavy shudder runs thru the whole truck
You can feel it in the sleeper, driver seat, shifter, steering wheel, dash .. the whole truck
It’s like 2-3 shudders a second
the vibration is worse with loads under 10k lbs and with 44k loads barely there
Tried 2 different trailers and no difference in vibration
Barely noticeable when bobtail
Clutch down and truck out of gear changes nothing so that rules out motor, clutch, flywheel
it’s literally shaking this truck apart

everything replaced so far
Driveshaft with slip yoke developed play so had a new one built from scratch
All drive angles are under 2.3 degrees
Ride Height at 2-5/8 inches
Alignment at truck rebuilder shop and he also checked pinion angles and ride height and said that was good
Also checked front end and everything was tight

no difference in shudder

transferred 8 wheels and tires from the truck I parked when I bought this one (I use centering bolts when I did this so wheels are centered)

No difference

New Eaton DSP 3.36 power divider after the
The Wheller reman front yoke had developed play and started to leak (not a fan of wheeler remans)
New axle shafts as well since the ones in the truck were Chinese aftermarket
New rear diff fluid(fluid was old but not burnt and no metal shaving)

no difference

had my dad drive his car around me on the highway and saw the drives wobbling
And confirmed when we put the truck on jack stands and ran it at 45mph
-4 new Conmet preset plus hub assemblies
-4 new premium balanced drums and shoes

no difference

interaxle shaft slip yoke developed play so had a new one built from scratch
Front two shafts were also checked and had carrier bearing replaced
-checked pinion angles again and all within spec

no difference

10 new Toyo tires
2 new steer Alcoa wheels
1 rear wheel was iffy
ALL balanced and centered with centered bolts
4 new Monroe magnum shocks
-alignment same day this time at Purcell and was good

no difference

new bushings and rebuilt Fontaine fifth wheel
New torque arms

no difference

I’ve pretty run out of ideas of what it could be
I’ve replaced everything that rotates in the drive portion of the truck
All the suspension bushing look great and are tight

I can’t remember the measurements from the top of my head but the frame of this POS truck doesn’t sit parallel to tfw ground
The front of the frame is 2.5 inches lower than the back
The front air ride is maxed out and the rear drive air bag sits 1 inch taller than the front drive air bag
I’ll try to sort that issue next but with pinion angles being under 3 degrees I don’t know if this would cause any issue

any and all insight will be greatly appreciated

crookedTRanspo · Mar 20, 2025

Literally the more I spend and the more things I replace I swear the truck gets worse.

I am putting in a 13 speed in the next week or so and will take driveshafts in to get shortened and I’ll have them recheck them but shudder is to heavy and consistent and slow to be shaft issue

crookedTRanspo · Mar 20, 2025

Also, NOTHING is heating up of wearing unevenly which is the most frustrating part

JB7 · Mar 20, 2025

crookedTRanspo said: ↑

Also, NOTHING is heating up of wearing unevenly which is the most frustrating part
Click to expand...

1 - timing of the driveshafts. Was the new driveshaft balanced?
2 - engine harmonic balancer. I read that you had clutch in and trans out of gear.
3 - engine and transmission mounts
Was the truck this way when you first bought it or did it start sometime after?

Deezl Smoke · Mar 20, 2025

the vibration is worse with loads under 10k lbs and with 44k loads barely there
Tried 2 different trailers and no difference in vibration
Barely noticeable when bobtail
Clutch down and truck out of gear changes nothing so that rules out motor, clutch, flywheel
and
The front of the frame is 2.5 inches lower than the back
The front air ride is maxed out and the rear drive air bag sits 1 inch taller than the front drive air bag

So now your inter axle drive line is is at a steeper angle than spec.
I'd want to know what front axle is under that air ride? I suspect your front axle may have too much drop.

Iamoverit · Mar 21, 2025

Why not take it to a good driveline shop (a shop with a dyno could be useful as well) instead of throwing endless amounts of money at it or asking random strangers that cannot see it in person to "diagnose" it?

201 · Mar 21, 2025

Such a shame people are spending so much money on these problems, being the skeptical type, these parts replaced could be junk out of the box. In a situation like this, they( foreign parts makers) know, it's not like it's a clear cut deal what's wrong, any number of things cause this, so they sell you inferior parts, they get their money, and it does nothing, or in this case, gets worse. If only trucks could talk, who knows what this thing has been through, and a million miles, it's clear, the truck has had it's useful life. It was so much easier with the old Transtars, they were made to last. Freightliner doesn't sell new trucks by keeping the old ones going. That carries over to the general attitude for all products today. Sounds like you have $20 grand in a $10 grand truck, I hope you get it figured out.

Deezl Smoke · Mar 21, 2025

What people "need" to understand, is that each of us is an individual. It's important that not everyone thinks or does the same as everyone else.
Everyone should take a step back and look at their own self. Many that condemn spending money on an older freightliner, spend 10 times that on a landscape for their house. It's just as stupid, or,....just as smart. It's all about individual views on life.
If anyone wants to talk about "controversial",.......just have a look at Wicked Intent. That guy has bigger brass than this whole board combined. I totally respect what he does and has done to his...... Freightliner.

Heavyd · Mar 23, 2025

For hops and shakes, I generally find any time the steering wheel shimmies back and forth, it is a steer tire problem. If you feel the whole truck shake or bounce and feel it in the seat, it is generally a drive tire. The frequency is not so fast to the point you can almost count the number of bounces. This is also consistent with a tire. Anything else simply spins too fast and becomes more of a hum or buzz. I take the truck, like you said, and put it up on jack stands again. Run it around 30mph or so and watch the drive tires to see if they are running out of round. Pick all the stones out first. If you run the truck at highway speed on stands, sometimes you cannot see the problem because the wheels are now spinning too fast for your eye to catch. The tire will be going up and down as it is rotating. Tires can be mis-mounted and wheels can be machined too big and not properly center on hubs even when they are new or have been swapped from other trucks. I find centering nuts do not always help, especially when the tire is not mounted true on the wheel in the first place. I hold a tire crayon very close to the tread of the tire and only the high spot of the tire makes contact with the crayon. Then adjust as needed. I hope this helps, good luck!

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