Power Train Vibration or Misfire

[hfitz7748]

Good evening,

Mechanic I'm not, so I thought I'd look to you all for some guidance. We purchased our Georgetown XL that has the Ford V10 in May, and since May we have had a vibration, or something that makes me think the engine is not running right between 45 and 60 mph. It is most noticeable when climbing a gentle grade. If I downshift into a lower gear, the engine obviously revs up and the sound goes away. This issue thus far, no one has been able to pinpoint the problem.

We've taken it to Ford, who on a test drive they say the motor is running great. They checked the balance of the drive shaft and it is good, and they pulled all tires, rebalanced, and they are good.

Road trip home today, same issue. I cannot properly explain the feeling or sound, but is feels like a vibration, but them it sounds to me like something just doesn't perform properly under the hood, almost like a warble sound (youtube has a warble sound, but you have to slow the speed of the warble down and give it a much deeper sound). It is a very annoying sound.

Has anyone ever experienced something like this? Any thoughts or comments very much appreciated. We are getting ready for a long trip and I cannot imagine listening to this for a long period of time.

Thank you in advance !!!!

[minnesota65]

Did they check the U joints and also it could be a tire separation inside tire sometimes cannot be seen

[Crusadernoob]

Sounds like a good description of a torque converter failing to me.

[JimF]

I’ve seen many threads on line here on misfire and vibration . The answer was always the serpentine belt slipping, why that I don’t know but cleaning the pulleys and replacing the belt belts seemed to correct the issue. Might try a search for the threads. I even copied down the replacement belt recommended. Will try and find my information and post it.
Safe Travels and good luck.

[JimF]

Found my notes “Continental Poly-V. It has groves cut diagonally in the belt. The belt part number is Continental # 4081102 (Use caution when buying belts, a lot of parts books show the wrong belt (99 incWe should have a 110 inch belt. If your not sure, measure your old belt with a tape measure.”
The pulley has groves in it this diagonal grove belt does not ride in the pulley grooves and doesn’t slip which is the problem with the factory belt, as told by previous poster. Haven’t tried this myself as we have not had problems, yet.

[Bluepill]

Very unlikely that you will find the answer on an internet forum. Noise/Vibration/Harshness are very difficult to describe. If you can be very particular, as in what road speed and what gear(s) it occurs, maybe someone will have a similar experience to share.

If you can have a few mechanics give it a road test, you may get pointed in the right direction.

Good luck.

[hfitz7748]

Thank you all for the response. The vibration or whatever it is occurs when under load and prior to it downshifting. When going up a slight incline in the road is when its the most noticeable. I've tried the tow/haul and nothing changes. The only way to make the noise go away is to drop it into 4th manually which increase the engine speed and obviously the engine noise. Whenever it is not under load, the noise/vibration becomes faint or goes away.

[hfitz7748]

One thing I failed to mention, we only have 1,300 miles on the rig.

[perrogie]

Two things that you can try; 1) with the truck standing still, brakes applied hard so it can't move, transmission in drive, start raising the engine RPM (brake torque) until you reach the RPM where the vibration comes in. This will often show up a missfire, which is often fixed with a change of plugs or wires. 2) With the trailer on, at the speed where the vibration happens, touch the brake pedal lightly to disengage the lock-up clutch in the transmission. The clutch sometimes has a partial slip mode that shudders because it isn't "engaged" enough. A transmission oil change will sometimes fix this as it changes the slipperyness of the oil. On higher mileage units we would add a product called Shudder Fix available at transmission shops. A warble noise is always caused by two vibration adding together to make a sound above an audable level. They could both be non-issues until they add together. Fix either one and it goes away. I was a transmission and driveline mechanic for thirty one years, been there, done that. Hope this helps.

[RACarvalho]

Can it be that you have a loose engine cover and the noise is in fact the resonance of that cover?

If the vibration/noise happens only at certain RPMs and the engine doesn't show any fail codes, the noise / vibration more likely is related to the frequency of the engine vibration, therefore something resonating as a response to the frequency (Hz)....

I would look for things that are not bolted properly around the engine bay...

[Bluepill]

Originally Posted by hfitz7748

One thing I failed to mention, we only have 1,300 miles on the rig.

Originally Posted by hfitz7748

Thank you all for the response. The vibration or whatever it is occurs when under load and prior to it downshifting. When going up a slight incline in the road is when its the most noticeable. I've tried the tow/haul and nothing changes. The only way to make the noise go away is to drop it into 4th manually which increase the engine speed and obviously the engine noise. Whenever it is not under load, the noise/vibration becomes faint or goes away.

Some observations:

Based on your low mileage, this problem may go away as the vehicle breaks in. Sometimes a motor mount adjustment helps. (All mounts loosened to allow the motor to settle, then re-tightened.)

It may also be the "Nature of the beast".. It sounds like the vibration is caused by the engine "lugging" at low RPM. With all the new MPG regulations, manufacturers are doing some stupid engineering to pick up the last 1/100 of an mpg. Lowering shift points is a very common trick, and has created many NVH (noise/vibration/harshness) complaints from customers of many brands. It may be something you will have to live with unless Ford issues a program update, as others have sometimes done.

[campdoc]

I also had the same issue recently. Low mileage and such. Thought all kinds of things i.e. drive shaft, u joints etc. Bugged the heck out of me n our trip to and from Florida. Ended up checking the spark plugs and coils. Found a carbon track forming on #1 spark plug, changed out the spark plug and coil boot. Ok now.
I am a Master Tech by trade. Hope this helps you.

[larry pw]

Ford had a recall on drive lines on mew vehicles. Check with the dealer. Some to rv upfitters

[hfitz7748]

Update:
Ford checked the drive shaft, U joints, rebalanced the wheels. Bottom line is we still have vibration, mainly between 55 and 57 mph. So, as much as possible, we avoid that speed. Crazy yes, but for now it appears we are stuck with the issue. Ford has had this RV now for 2 different times and 2 weeks at a time, but no luck figuring this out. I know they are driving and testing it because they burned up about a 1/4 tank of fuel. We'll put some miles on it and see what happens. Thank you all for your comments ans suggestions.