When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
My 2000 7.3 4X4 Excursion has developed a vibration (currently 350k miles). This vibration is most noticeable
between 58 and 73 MPH. Vibration seems to be coming from the rear of the vehicle. There is a slight torque component to the vibration (feels different when under power (foot in throttle) vs. slack (foot out of throttle). I will describe sequences leading up to today:
1) Replace all leaf spring, sway bar, track bar, even body mounts with urethane bushings.
2) Add-A-Leak on all 4 leaf packs. Doesn’t fit the profile listed in the Vibration Diagnosis Details over in the tech folder, added for consideration. Vibration began 2500 miles after this work was complete.
3) Installed Roadmaster active suspension. Again doesn’t meet the profile, added for consideration. Vibration began 2500 miles after this work was complete.
4) Installed Sulastic Rubber Springs/Shackles on front and rear leaf springs. Again doesn’t meet the profile, added for consideration. Vibration began 2500 miles after this work was complete.
5) Installed Hellwig rear sway bar. Again doesn’t meet the profile, added for consideration.
6) In concert, the 5 items above were done simultaneously and resulted in 3.5 inches of lift. But again vibration began 2500 miles after this work was complete so I don't think pinion angle is the problem.
7) Replaced Upper and Lower Front Ball Joint. Doesn’t meet the profile, added for consideration. Vibration began 1000 miles after this work was complete.
8) Tires Rotated/Balanced - No Change in Vibration.
9) New U-joints in Drive Shaft and Greased the slip joint – Vibration slightly got worse.
Took to a transmission shop (quality of workmanship unknown) for differential servicing and inspection in hopes that this would result in something meaningful in this vibration chase. During the inspection, the technician sent me the below pictures and said: “I’ve never seen anything like this in my 30 years in the business”.
He closed up the Diff, filled with fluid and said: "Nothings rubbing, here's your bill, good luck."
Not sure what to do Next. Anybody ever seen this kind of gauling on a carrier?
Did you have the drive shaft lengthened or checked since you added 3.5 inches? When I say checked, measure from the flange face of the transfer case to the flange on the pinion. Take that measurement and your driveshaft to a good drivetrain shop and ask them to check it. The slip joint in your drive shaft can only be extended so far before it will start to show vibrations like you are experiencing. I am going through similar situation right now. I lifted rear 2.5 inches, replaced both U-joints and greased the slip joint. I started getting vibrations in a very narrow band between acceleration and deceleration. Nothing on acceleration; nothing on deceleration. Turns out, I likely screwed up the phasing of the drive shaft and possibly need to have it extended.
Pirate4x4 should be along shortly to comment here. He is an expert in this arena of discussion.
I was thinking of taking it to a driveshaft "specialist" for a balance check. But then I think how does a driveshaft get out of balance it doesn't have any damage?
I was thinking of taking it to a driveshaft "specialist" for a balance check. But then I think how does a driveshaft get out of balance it doesn't have any damage?
You possibly have a length issue that needs to be checked. Any maintenance...like changing out u-joints...can put the shaft out of balance or out of phase.
You possibly have a length issue that needs to be checked. Any maintenance...like changing out u-joints...can put the shaft out of balance or out of phase.
It is my understanding that “Phase” is a specific condition that is directly related to the angle between the Pinion and the rear end.
Is 3.5 inches of lift enough to put the pinion and rear-end angle into an out of phase condition?
To me that looks like the pinion gear is rubbing on the carrier. That is the only possible explanation for that type of wear pattern. Even if they said there is no rubbing I would pull the cover and take a look for myseld. But I am no expert..
You might want to have a driveline shop measure the backlash on the differential (If you don't have the dial indicator to do it on your own). I am thinking on that either the pinion bearings or the carrier bearings are shot. You could also the do grease check on the gears like when you do an install to check for the contact pattern.
Edit: The driveshaft could've cause the problem the problem if it is the pinion bearings. Abnormal stress on the pinion yoke destroyed the bearings. But at 350k miles, it may just be worn out especially if the fluid was not regularly serviced.
Engage 4wd
Remove the rear drive shaft
test drive in front wheel drive.
if the vibration is present when the rear driveshaft is removed then the issue is in the rear axle/wheels
if the vibration is gone then the issue is either your rear pinion angle or as noted above a ujoint or the slip yoke.
In summary, the driveshaft is in question. I will focus my next round of this science experiment on that component.
Is it “safe” to drive 60-80 mph in the front drive only configuration? My truck has seen very little engagement of the front driveline, but I know it’s all functional.
You could also the do grease check on the gears like when you do an install to check for the contact pattern.
The shop "SAID' the did a grease check and the surfaces were matting as expected. I asked them to give me the ring gear backlash measurements and they "SAID" we don't have that tool, that's when I knew I was NOT using the right shop. In their defense they are a transmission shop, SO I guess that what I get.
In summary, the driveshaft is in question. I will focus my next round of this science experiment on that component.
Is it “safe” to drive 60-80 mph in the front drive only configuration? My truck has seen very little engagement of the front driveline, but I know it’s all functional.
Yes it is safe as long as your front axle and related components are in good working order.
you can drive at 55 mph in 4 high as long as you are not on dry pavement, with the rear driveline taken off the vehicle there will be no binding. When you drive in 4x4 with the rear driveline installed the front and rear are locked together and the tires need to be able to slip ( like on a dirt road or snow ) to eliminate the bind.
Fwiw, everything is in question, this test just helps narrow down the area you need to hone in on.
but if I were to guess it is your pinion angle after the spring changes, but the slip yokes is also a good candidate since where the spline are engaging inside of it has also changed after you altered the ride height. Basically anything that was changed when you altered the ride height is most suspect, Or it could just be coinsidence and something else wore out just so happened to after the change..... those would be ujoints, tires, rim, ect.
entirely possible the new driveline angle pissed off your ujoints so they decided now would be a good time to fail, or maybe your wife hit a curb and bent a rim and forget to mention it to you..... but that never happens.
Yes it is safe as long as your front axle and related components are in good working order.
Excellent, I will give this a try and report the results in a few weeks when I can get to the test (Or sooner if it fails) this is my daily driver, so....
Have some red loctite on hand when you do the test. You will need to clean your driveshaft bolts of the old loctite and put new loctite on them when you re-install.
I am getting my drive shaft back in the morning. He told me the 2 inch lift is still within operating range of the slip joint. My new measurement from flange to flange is 52 5/16"...you might check yours for comparison. $87 to balance and re-phase mine.
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Slideshow: The VelociRaptor Expedition gains a lift, upgraded suspension, Brembo brakes, and trail-ready equipment while retaining the stock 440-horsepower EcoBoost V6.
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
