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Topic: Harmonic & Vibration in Rear End (Read 1005 times) previous topic - next topic
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Harmonic & Vibration in Rear End

Yahoo Message Number: 26141
We have a harmonic (noise) and vibration stemming from the engine, transmission, rear axle area. It occurs at about 50 mph under light load and dminishes by 60 mph. The greatest intensity is felt in the hallway/bathroom immediately above the drive train area. However, vibration can be felt through the steering wheel and even the accelerator pedal. It is very disturbing and annoying to the point where we have to pull over periodically to unwind, but moreso we are not using the coach for extended travel due to the potential that something will break.

We traveled to the factory where CC addressed the problem by replacing the rear end, the drive shaft, all shocks, 5 tires, and assuring correct ride height. None of this corrected the problem.

We (owners) are continuing to investigate the cause of the loud noise and associated vibration. We entertain any constructive ideas for further diagnosis of the cause that you can provide us.

Thanks,

Jim and Joyce Posik
06 Intrigue 40' 400 ISL

Re: Harmonic & Vibration in Rear End

Reply #1 –
Yahoo Message Number: 26143
Did they retest the unit on the CC dynamometer? As I recall they send the tires out, why did they leave just one tire and replace 5? Did they check rims? Other items, engine mounts, transmission mounts, any exhaust components touching frame? You have the generator off? Does it do the same thing going up or down hill?

Re: Harmonic & Vibration in Rear End

Reply #2 –
Yahoo Message Number: 26149
Re-adjust rear ride height to within spec. This part is important... the height must be within specs as measured with both front air bags and rear air bags on the rear axle. Then bring your front end up to spec and recheck the rear and readjust if needed. That rear axle has to be riding level or the ring and pinion become loaded and then we have noise.
AL

00 affinity #5851

Re: Harmonic & Vibration in Rear End

Reply #3 –
Yahoo Message Number: 26157
Jim,

Try having the rear wheels checked for lateral and vertical run out. It is very simple to do by removing the tires and spinning the wheels on a stationary balancer and measuring the run out with a dial indicator. CC must have a acceptable run out limit for your coach since no wheel is perfectly round or true

We have a harmonic (noise) and vibration stemming from the engine, transmission, rear axle area. It occurs at about 50 mph under light load and dminishes by 60 mph. The greatest intensity is felt in the hallway/bathroom immediately above the drive train area. However, vibration can be felt through the steering wheel and even the accelerator pedal. It is very disturbing and annoying to the point where we have to pull over periodically to unwind, but moreso we are not using the coach for extended travel due to the potential that something will break.

We traveled to the factory where CC addressed the problem by replacing the rear end, the drive shaft, all shocks, 5 tires, and assuring correct ride height. None of this corrected the problem.

We (owners) are continuing to investigate the cause of the loud noise and associated vibration. We entertain any constructive ideas for further diagnosis of the cause that you can provide us.

Thanks,

Jim and Joyce Posik
06 Intrigue 40' 400 ISL

info/terms/

Re: Harmonic & Vibration in Rear End

Reply #4 –
Yahoo Message Number: 26199
Al, Good advice! I agree 100%. However, ride height was checked at the factory in June on 2 different occasions, and the tech reported that this coach was one of the closest ride heights he has ever encountered. But I think I'll check it again myself after reading the manual for instructions. as I've never done it before. Is it tricky?

Jim 06 Intrigue

Re: Harmonic & Vibration in Rear End

Reply #5 –
Yahoo Message Number: 26200
Paul, This was done by Les Schwab to a point. The run out was measured not on the coach, but on a machine, and as a result, 3 out of 6 rear tires and 1 rim had to be replaced on the rear because of run out. Wonder if I need to check it again?

Jim 06 Intrigue

Re: Harmonic & Vibration in Rear End

Reply #6 –
Yahoo Message Number: 26207
No, not at all. Couple of suggestions, as I heard the same story with my coach. What a statement by the tech when he says" that's the best I've ever seen". Then why do you have rear end noise ? Get the specs from country coach.... one of the free things.
Make sure your fresh water tank is full. This will put some weight in the rear and act as stabilizer. Then make sure you are on level ground.
I made a jig on a piece of cardboard for the front air bags, which I will say made the front very easy to do.
You will never get the front air bags to be the same, because you only have the one ride height control. I better say you could if you played with the rear. Your main concern will be the rear ride height. Let me know where it was in relation to the factory spec. Thanks.
Question, when is coach is on level ground does it sit level?