vibration???
 

I have 2005 freightliner with a cat c15. the front end shakes, i had the tires balanced and front aligned but didnt fix it. It shakes more going up hill and over 65? the truck has 550,000miles, what can i check next to fix the problem?

check this out,look at the aluminum hub, look at the drum alignment tangs,and also they align the rims on the hubs also. after time they get worn,basically corode and fall to pieces,and dont hold the drum squarely on the hub,causing the vibration.also fare they oil packed hubs or the merritor sealed hubs?

https://mis.conmet.com/HubCatalog/Hu...s/image002.jpg

see the wheel pilot diameter,and the drum pilot diameter,look at the tangs and see how badly the drum wobbles on them.

http://www.conmet.com/pdfs/Hub_Service_Manual.pdf

page 6 shows the tangs in better detail.also this is the manual of the hub.

vibration
 

You might also check your u-joints, or back tires, many times a vibration radiates up thru the steering wheel, making it feel like it's in the front end, but it could be originating elsewhere. Going up hill does put more strain on the driveline. Vibrations can be very elusive.

When you had your front end aligned they should have checked your other front end parts, but it would be good to check te rods, king pins, shocks and see if there is anything that might be loose on the front end. If you have dipping on a tire that could also cause some vibration as could a belt coming out of your tire.

You may also check your drive tires to see if there are any tires that have dipping or flat spots. Sometimes, vibration can be a little difficult to pin point. I would check my entire suspension to make sure that everything is tight. It doesn't take much for a vibration. I believe someone else mentioned checking your drive train. It is sometimes a process of elimination.

Universal joints would be one of the first things I would check.

also check the ride height. i think it is 2 3/4" from top of the spring u bolt pad to the bottom of the frame bump stop bracket,for that year.

Kingpins....

is the vibration more in your hands or the seat of your pants? hands mean front end, pants back end. have you had the front wheels off lately? if so try loosing them have someone put a light brake application on to center the brake drum and retorque the wheels.

vibration
 

Ive taken two light loads east to west I10 to Cali. I think the shake comes under tourque, like up hill. I coasted down a nice mountain and the shake was not as bad.
But up hill th cat cat seems to vibrated more int the floor. could it just be a cat? I hear they run loud. Could be a lot of things but she still roll up that hill. May be u ujoint?

different tires can cause vibration. when I had hwy tires on my drives, no vibration. when I put 8 new kelly kda lugs it would bounce & shake my eyeballs until the tires wore down a bit. 3 axle alingnment & new steers did nothing. the kelly's were wearing even too. just with that type of tire on my truck, it road different than others. I will say that the kelly's are quite a bit taller than other brands of the same size.

Drive axle alignment?
Seems I had this problem once, and that made a difference.

If you have eliminated the other suggestions, you might check your fuel lines. Your stated mileage is is minimal for this, but entirely possible. What happens is the interior of the fuel lines start to collapse, cutting off your fuel. This is magnified under a pull.

A torque sensitive vibration is usually coming from the driveline.

Check for loose yokes at the output shaft of the trans, and at the input shafts of both diffs and the output shaft at the rear of the power divider on the front diff. Also check for worn slip joints on each driveshaft, and worn U joints.

I just thought of something else:

Check the harmonic balancer at the front of the crankshaft too, a defective or worn out balancer will cause vibration on a hard pull, and will eventually result in a broken crankshaft if you continue to run it that way.

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how about the crankshaft vibration damper? pittsburg power says they are only good till 500k mi. if your mileage is higher than that, maybe you should have the damper checked because if it doesn't do its job properly your vibrations will increase. pittsburgh power sells new ones for cat engines for around 300 bucks.

Could be many things:

Worn input shaft
Clutch worn/out of balance
Worn engine mounts
Sloppy spring bushings
Tires out of round
Drums out of balance
Exhaust leak under cab
and what already was said...