Originally Posted by Fish
Have been monitoring the Forum for some time. Really good stuff. First post though. Bear with my "newbieness".
Any of you out there know of or have any experience with drive-train vibration in a Class C? Kindof a long story--so I’ll summarize. I have a Thor Four Winds 31W--2016--purchased in June of 2019 with 22,000 miles on it. In February of 2020, I took it to a local Ford dealer (their commercial truck shop) for inspection, front end alignment, steering stabilizer replacement and heavy duty sway bar installation. At the time, when they took it for a test drive, they indicated they felt a significant vibration and suggested having the drive shaft balanced. I had not really noticed the vibration previously, but then the unit was new to us and after having towed a 5th wheel with a 3500 dually for a number of years, the Class C diving experience was totally new. So, I had that work done too. They sub’d it out to a local shop that specializes in drive shaft work.
What I noticed, once I got it back, is that there still seems to be drive-train vibration that begins low cycle vibration at about 45 mph, peaks at about 55 and then starts to decrease at 65. Since there’s still warranty left, I have it back at the Ford garage for evaluation.
I’ve tried researching the Forum to see if there’s any history on this topic, but have not found anything. So I thought it was time to put the question out there to you experts to see if anyone’s been down this road before and can help me help the shop resolve this.
Thanks in advance for any insights you might have.
The Ford 90 degree V-10 has three vibration periods. Two are somewhat canceled by the engine's balance shafts and engine motor mounts. The third one is around 2,000 rpm and again in the 4,400 rpm range. Mine is severe enough to make the tailpipe hit the heat shield on the coach.
You could have a driveshaft that is out of balance but MorRyde usually does a good job of balancing the drive shaft before Thor MC gets the chassis. Inline 5 cylinder engines are notorious for the vibrations. So much so that they require active engine mounts. Putting two together in a 90 degree engine does not make then vibrate any less.