Hi Everyone,

I had a whining ring and pinion around the 40-50 mph range and at 75-80 a terrible and I do mean terrible loud humming vibration. The ring and pinion and all bearings,cups, cones and all the parts contained in the rear axle were replaced. The 40-50 whine is gone but the dealer cannot find the cause of the humming vibration at 75-80.

The sound happens when you accelerate or hold gas pedal steady through 75 to 80 but if you let off the gas it stops. Dealer says it is not drive shaft, is not U-joints, is not torque converter. My tires are brand new Goodyear Fortera Kevlar Silent Armour, only 1200 miles on them and no steering wheel shimmy at any speed.

My 2003 Edge 3.0 Auto is well cared for, not modified, 41,000 miles.

Any ideas guys?

Thanks a ton!

 

did it do this before you got the ring and pinion done? I know both my 01, and o4 ranger 4.0 starts to hum and vibrate ate close to 80mph. All of the other new rangers that I have driven do the same thing. It may be normal, but I would need someone to back me up on that one.

 

did it start when u got the new tires on? i had this and the ppl who mounted and balanced did not balance them right. and another time a weight fell off the rim and it would do this at 75mph.
i still have a slight vibration but its now at 85 and i know its from the tires thet they did not balance them right again lol

 

Hi Guys,
Yes my Ranger had this humming vibration between 75-80 before the ring and pinion were replaced.

The sound and vibration is extremely gas pedal sensitive so I would think you could rule out tires or balancing. My steering wheel is shake free from 0-90. This vibration/hum certainly feels engine/driveline/tranny related to me. But what is it.

I really wouldn't worry about it but I drive the Ranger 90% on the highway and wouldn't you know it that traffic moves exactly 75-80mph.

 

My guess is driveshaft balance. My truck had an imbalance from new at 68 MPH+. It took some arguing but the dealer finally replaced the original driveshaft under warranty. Now the imbalance has moved up to 75~80MPH+. It is probably not as severe as what you're describing but it is still there.

We all know what an out of balance tire feels like. A driveshaft imbalance has a higher frequency - about 4 times as high. So it feels more like a buzz than the thump that a tire/wheel imbalance gives. That's the best way I can describe it. It usually happens at high speeds and gets worse as speed increases.

I would give the driveshaft a quick inspection to see if there is an obvious dent or a blob of undercoating or something else that would explain the vibration. If not, you can attempt to improve the balance by reorienting the driveshaft.

 

Hi Bob,
I really think it is drive shaft related too. There is nothing stuck on the drive shaft except the OEM weld blobs that they balanced it with at the factory. No dents, nothing unusual.
But the dealer nor Ford is replacing it. Wonder if I should do the old band clamp trick to see if that amplifies the problem or corrects it somewhat?
Thanks, and keep the ideas coming.

 

So, it's a buzz when you're getting on it at those speeds or just cruising? I have the same "buzz" thing happen when I'm hammering the gas and as soon as I let off the truck rides smooth, it's done this since it came off the lot.

 

Yes, that's one way to do it. I would use a pair of spiral hose clamps. Just clamp them on the rear of the driveshaft body and try different combinations of positions to optimize it. A second set of 2 can be added to the front of the shaft body for more experimentation. If the "best" setting is with the 2 adjusters directly across from each other, then obviously you don't need the clamps on that end of the shaft.

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Here's another way that the dealers sometimes use. I have to get busy and do this to mine to see if I can push the onset of the vibes to a higher road speed.

Mark the original location of the driveshaft flange relative to the rear axle flange where it bolts on. Then remove the 4 bolts, rotate the driveshaft 90 degrees, reinstall and retorque the bolts. Test drive to see if there is an improvement.

Repeat the above steps two more times, rotating it 90 degrees each time in the same direction and retesting each time. When you're done, you will have tested it in all 4 possible positions.

You will probably find one or two settings that are better than the others. Pick the best orientation and install it there. Replace the bolts (or at least coat the threads with threadlocker) and be sure that they are correctly torqued to spec.

You can also do this at the front of the driveshaft. 4x4's bolt to a flange in the front just like at the rear. 2WD driveshaft assemblies have a splined slip yoke that slides into the transmission tailhousing over the output shaft splines.

The 2002 shop manual lists the torque spec for the flange bolts as 83 lb-ft.