TV Vibration


May 20, 2015
Filed under RV Tech Q&A


We own a 2005 Phoenix Cruiser 2350 motorhome. It has a flat-screen TV that is mounted on a swivel arm located over the cab area, between the driver and passenger seats. When traveling, the TV vibrates and rattles; this gets worst at highway speeds. We have tried a number of ways to stop the vibration. I have tried putting padding around the area and even stuffing a pillow behind the TV when we are traveling. However, none of these has been very effective. In addition to being very distracting, I’m sure this vibration is not good for the TV. I hope you have a solution to this problem.
Chip Bradstreet | Stockton Springs, Maine

CP-TVWhenever you have a TV on an extension arm, unfortunately it magnifies the road vibrations. Other than mounting it elsewhere, which wouldn’t be easy in a compact motorhome, you might try using nylon straps and brackets that can pull it toward the bulkhead and stabilize movement while driving.

A Challenge

In a previous column you said you love a challenge. Here’s one for you. We have a 2005 Fleetwood Jamboree GT on a Ford E-450 chassis with 11,000 miles. The problem is a harsh noise coming from the engine/transmission area. The symptoms are as follows:

First, when traveling at exactly 58 mph, a grinding/scraping noise (similar to driving over a steel grid bridge deck) can be heard.

Second, when traveling at 62 mph (with cruise control on) and entering a slight incline (1-2 percent grade) there is a chugging, pulsating sound that disappears when the transmission downshifts to a lower gear.

Third, when traveling at 62 mph (with cruise control on) and entering a slight decline (1-2 percent grade) there is a bucking motion that’s felt until the terrain becomes level.

A Ford truck dealer checked it out and found no problem with the U-joints, driveshaft center support bearing or differential pinion bearings. I also visited two shops that specialize in driveshaft problems and they were unable to offer a solution. I checked with Fleetwood RV service and they told me they have not had reports of this type of problem. Do you have any ideas?
James Kunik | LaGrange Park, Illinois

Finding a problem, or set of problems such as this can be very difficult to diagnose, as you have discovered. Understand that without having the motorhome to drive and check over, I can only offer a guess.

Vehicles give off frequencies during operation, which change with load and RPM. Tire vibrations and driveline imbalance both become prominent as these highway speeds are reached. Assuming you trust the dealer’s diagnosis, my best guess on the first problem is that something like an exhaust heat shield is vibrating when it hits a certain frequency, which is why it doesn’t do it at other speeds. It’s necessary to do a very careful, thorough inspection of heat shields top and bottom, using inspection mirrors where necessary. Move them around by hand (when cool of course). Look for telltale rub marks where they vibrate against floors, exhaust pipes, mufflers and catalytic converters.

The second problem is likely that the engine is lugging very slightly at that speed and this vibration frequency is being felt through the lockup-torque converter through the drivetrain and into the vehicle. An easy way to verify this is to have a technician ride along with a scan tool connected to the vehicle, which can command the converter clutch to lock and unlock.

On the third problem, I believe it is likely that the cruise control is causing the bucking motion as it adjusts throttle position. Slight variations in gradient, which may not even be visible to the driver, can cause this. Again, a scan tool (available at the Ford dealership and other shops) can verify cruise control operation and throttle position changes during a test drive to confirm this as a cause.

Finally, and this sort of goes back to basics, have the balance checked on all of your wheels. If one is out of balance its vibrations can cause a feedback through the drivetrain and chassis at certain speeds and that can affect the rest of the rig. I’d be happy to hear from other readers who have experienced and solved similar problems with their motorhomes.

Big Batteries

I own a 1988 Bluebird Wanderlodge powered by an 8V92 Detroit Diesel. These beasts were equipped with six batteries; I’m not sure what the original configuration was, but mine has six 12-volt batteries wired in parallel, servicing both the engine and the coach. They’re no longer holding a charge so I’m upgrading. Reading your columns, the way to go seems to be 6-volt batteries in series for better life when boondocking. So should I go with three pairs of 6-volt batteries, or separate the engine from the house and use a pair of 12-volt high CCA batteries for the engine and four 6-volt golf cart-type batteries for the coach?
Mike Williams | Fruit Heights, Utah

I definitely recommend using two pairs of 6-volt golf-cart batteries to power the coach when you are off the grid. I was working for a GMC truck and Detroit Diesel franchise when this engine came out, and I can still remember how much power they required to get them started on a cold morning! As you note, the original equipment was 12-volt batteries in parallel for engine starting. There are a lot of diesels running around the country with a pair of 12-volt batteries for starting and I recommend going that route, using the original equipment size and type.

RV Leans While Driving

My wife is an avid RVer and I am an occasional RVer. To satisfy her gypsy spirit, she has a friend with an RV that goes on road trips with her. She drives a 2012 Thor Challenger 37-foot motorhome. Generally, my wife tows a Honda CR-V and follows her friend down the road. Since her friend purchased the RV, my wife has noticed that the vehicle leans to the passenger side while driving. Lately her friend has been complaining about the back end wagging when turning or when a truck passes the RV. When the RV is parked, it appears to be level. Recently, while getting the door step repaired, the service man mentioned to her that a TruTrac suspension stabilizer for the rear and a TruCenter for the front would cure this problem. To me, it seems like the suspension on the F53 chassis’ leaf springs or shock absorbers are the real problem, but I am not sure. What is your opinion?
James Rodda | Orange, Texas

Shock absorbers (unless they are air shocks or have coil springs wrapped around them) don’t support weight and therefore don’t affect ride height. So we can eliminate them as a cause of this problem. Most roads have a “crown,” which means the center of the road is slightly higher than the edges, to facilitate water runoff and proper drainage for safety. This crown causes tall vehicles such as motorhomes to lean outward slightly, and it can be several inches as it is accentuated by the height. If the coach appears straight-up level when parked in level areas, this is likely the culprit. This can be verified by measuring the ride height when it is parked on a flat level pad. Measuring from the pavement up to the center of the wheel openings directly above each axle is a rudimentary method. It is possible that the body was not formed exactly the same on both sides. If you want to be more accurate, measure from the ground to the bottom of the frame in the same spots on both sides, near the axle centerlines.

If you find that one side is significantly higher than the other, weigh the coach on a truck scale. Get individual wheel weights if possible. Often, the coaches are built with substantially more weight on one side or corner although the manufacturers have been better about this in recent years. It is also possible that one spring has sagged more than the opposite one. However, if there’s several hundred pounds of difference from side to side, it may be necessary to add a short leaf, install all new leaves, or otherwise prop up the lower corner(s). A spring shop that works on trucks can help you get this sorted out, but before doing that you might be able to shift items that are loaded in the motorhome.

The swaying is a separate issue that has to do with chassis design. We get many complaints from readers about the F53 swaying and tail wagging. The Davis TruTrac is a type of Panhard bar that helps position the rear axle more solidly so it doesn’t move side to side as the springs flex. The Blue Ox ( TruCenter goes on the steering linkage and allows the driver to adjust steering wheel pull, sort of like rudder trim on an airplane. Blue Ox also offers the TigerTrak, which is designed to do a similar job as the TruTrac, and SuperSteer ( also offers a Trac Bar designed to handle tail-wagging issues. In our experience, installing a rear-end Panhard bar is one of the most effective steps you can take toward improving your motorhome’s stability.


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