Chassis Vibration

[Roger.H]

We just took delivery of a "new" 07 Alfa coach on a Freightliner XC chassis with a Mercedes engine with 2000 miles. On our first drive from the Fort Worth dealer to San Antonio we encounter a vibration. It happened about six times during this trip. The vibration slowly increases in amplitude, then dampens out and stops. The frequency seems to be about the same as tire rotation speed. When it is at is maximum amplitude, the shaking is very noticable somewhat like a very out of balance tire. I drove at 55 to 60 and it does the shake intermittantly. I drove at 65 for an hour and it did not do it. When it is shaking there is no feel of vibration in the steering wheel.

Took it to the local Freightliner dealer. We took a test drive and got it to do it once with the Freightliner tech, but not as big of a shake as it has done in the past. He jacked up the front spun up the tires and checked it out. He could not find anything wrong, suggested I go to another local tire shop for a tire balance and trueing of the tires. I did this, and on the next trip it did the same thing. Freightliner says it is the tires, so I went to a Goodyear dealer and they said it was a Freightliner issue. At $145 per hour the Freightliner dealer runs up a big bill quickly, and Freightliner warranty did not cover it.

Anybody ever have this problem with your Freightliner?
Any suggestions on how to get it fixed?

Roger & Kathy

[Pusherman]

I had a problem with my 07 Journey (on a Freightliner XC '06 chassis) when I took delivery. The unit had several driveability problems, including a vibration and a tracking issue. To make a long story short, I ended up taking it to an independent alignment shop who can handle large (bus) chassis. They checked alignment. Spot on. They checked square of the chassis. Spot on. They also balanced the front tires/wheels while on the chassis. Problem was here. Turns out the 2 front tires were out of round.

I then contacted Michelin and they replaced the tires under warranty.

Take it to a good independent shop and have them take a look. You may have to pay the bill, but it will be worth it. If they find an issue, you can then go back to the appropriate manufacturer for a warranty claim (except Alpha of course).

[Roger.H]

Don,

Thanks for the input. My front tires (and probably the back) were also out of round. The local tire shop actually shaves some tread of the tires as they turn them making them round, then balanced them on the coach. It made a big difference, it is completly smooth driving down the road, i.e. better than before. However, the intermittant vibration issue did not go away.

Roger

[J Walker]

I vote for out of round especially on Good Year tires. Take it to a shop that can check and fix this. Shaving the tires may be necessary. That is where I would start especially if the problem varies with speed.

[Getting Old]

Had my tires balanced at a truck tire shop with "Equal" and put up with the vibrations until I got to Gaffney. They said it was a very common problem with IFS and replaced the Equal with lead weights and had a smooth ride home.

Don, WIT 70041

[Gary RVRoamer]

The other possibility is a drive shaft that is out of balance (rare on a pusher with short shaft) or a bad universal joint.

I'd bet on a tire that has a tread separation internally and it gets out of balance at speed and under load. It doesn't always show up when spun on a machine. You could try moving the tires around to see if the vibration moves with it.

[jimandsue60]

I thought Freightliner bought back all the Mercedes powered Alfas and re powered them with Cummins?


Jim

[JMJCSIM]

We had the same problem with our '07 Freightliner, but we have a Cat C7. Ours would vibrate at the same RPM range, 1500-1800, which was about 55 miles per hour. It vibrated more while under a load. After several trips to the Freightliner dealer, I took it to the Cat dealer and found a fouled injector. The Freightliner dealer thought it was tires, the driveshaft, and even the transmission. Haven't had a problem since.

Good Luck!