Vibration Fix
05-21-2015, 08:17 AM
#1
Junior Member
Thread Starter
Vibration Fix
Has anyone found a fix for the chassis vibration. Everyone at Ford says this is just part of the characteristics of this vehicle. I can not believe that someone has not found the magical fix with so many issues.
I love my truck but this is really annoying.
I love my truck but this is really annoying.
05-21-2015, 11:20 AM
#2
IMHO Ford doesn't want to invest the time, resources, and capital to resolve. This issue has been complained about at nauseum for years on the 6.5' bed configuration trucks.
I have a 2 piece rear driveline. In all my research and trial lead me to a few possible suspect areas. Some are easier to address than others.
#1 Yoke phasing
#2 Driveshaft and U-joint operating angles
#3 Transmission mount
#4 Less than "best" configuration (carrier bearing/slip yoke)
I sorted through industry known best practices from Spicer and other sources on proper driveline operating angles and configurations.
The yokes should either be in phase, or 90 degrees out of phase depending on configuration. My best assessment was my config was suppose to be in phase, found the factory had a 16 degree disparity. I separated mine and clocked it at 1.6 degrees which is within the 3 degree specification. This helped some. Documented the video before and after evidence (non-scientific).
The OEM driveshaft run-out acceptable specification seems to be less than optimum.
Using a Spicer white paper. Found that my configuration didn't match any of the suggested angle ranges of operation. The Spicer specification calls for the jackshaft (shaft directly connected to transmission or transfer case) to be at the same angle as the pinion. I added pinion shims, to bring the pinion nose up, dropped the carrier bearing 1/4" and finally rigged the leaf spring isolators to engage the above leaf sooner in the travel range. This has helped immensely. Need more miles on it to validate. Haven't tried this setup with any real payload in the bed yet.
The stiffness of the transmission mount seems woefully inadequate to quell most all motion induced to the driveline, which allows any movement of the components to pick up a repeated oscillation, felt as a vibration. There are numerous videos on youtube that document this issue. Most prevalent from a dead stop, gets worse when load is applied, doesn't aid, quell or prevent the oscillating vibration at speed.
The "better" configuration driveline for those with a two piece rear shaft design is a fixed carrier bearing, double cardan joint and a slip joint build into the rear most shaft. This setup is around $600 to $750. Last resort for me. This would resolve the slip/bump/clunk compliant and having to lube the carrier bearing slip yoke on intervals. The double cardan joint would also totally resolve any phase induced vibration.
Youtube is loaded with best practice information, education and demonstration videos on proper driveshaft setup, phasing, angles of operation. The physics involved is amazing for what appears to be a simple component.
In summary on my truck there appear to be many small suspect areas that contribute to the larger experienced issue.
I have a 2 piece rear driveline. In all my research and trial lead me to a few possible suspect areas. Some are easier to address than others.
#1 Yoke phasing
#2 Driveshaft and U-joint operating angles
#3 Transmission mount
#4 Less than "best" configuration (carrier bearing/slip yoke)
I sorted through industry known best practices from Spicer and other sources on proper driveline operating angles and configurations.
The yokes should either be in phase, or 90 degrees out of phase depending on configuration. My best assessment was my config was suppose to be in phase, found the factory had a 16 degree disparity. I separated mine and clocked it at 1.6 degrees which is within the 3 degree specification. This helped some. Documented the video before and after evidence (non-scientific).
The OEM driveshaft run-out acceptable specification seems to be less than optimum.
Using a Spicer white paper. Found that my configuration didn't match any of the suggested angle ranges of operation. The Spicer specification calls for the jackshaft (shaft directly connected to transmission or transfer case) to be at the same angle as the pinion. I added pinion shims, to bring the pinion nose up, dropped the carrier bearing 1/4" and finally rigged the leaf spring isolators to engage the above leaf sooner in the travel range. This has helped immensely. Need more miles on it to validate. Haven't tried this setup with any real payload in the bed yet.
The stiffness of the transmission mount seems woefully inadequate to quell most all motion induced to the driveline, which allows any movement of the components to pick up a repeated oscillation, felt as a vibration. There are numerous videos on youtube that document this issue. Most prevalent from a dead stop, gets worse when load is applied, doesn't aid, quell or prevent the oscillating vibration at speed.
The "better" configuration driveline for those with a two piece rear shaft design is a fixed carrier bearing, double cardan joint and a slip joint build into the rear most shaft. This setup is around $600 to $750. Last resort for me. This would resolve the slip/bump/clunk compliant and having to lube the carrier bearing slip yoke on intervals. The double cardan joint would also totally resolve any phase induced vibration.
Youtube is loaded with best practice information, education and demonstration videos on proper driveshaft setup, phasing, angles of operation. The physics involved is amazing for what appears to be a simple component.
In summary on my truck there appear to be many small suspect areas that contribute to the larger experienced issue.
Last edited by joedotmac; 05-21-2015 at 11:42 AM.
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Pirate Edward Lowe (05-26-2015)
05-22-2015, 07:38 AM
#3
My truck had been to the dealer 5 times and for a total of 23 days. The last time they had the driveshaft balanced. Truck still has the same vibration. Have been looking at the pinion angle but have not found any specs as to what the factory angle should be but mine is around 3 to 4 degrees up. Was also thinking about doing exactly what you have done but am unsure of how much I need to move it. I guess it's up to me to figure it out since Ford hasn't been much help.
05-22-2015, 09:23 AM
#4
Senior Member
I'm dealing with it too. But I have a 4" rear block. Only notice it now(Did not notice it with 2 1/4" blocks and no center bearing shim), but the drive shaft was replaced under warranty 5-8K ago. And I bet the splines are dry, so I am replacing the transmission/transfer case mount with one from a 6.2L which is stiffer and should stop some movement, and greasing both splines in my two piece shaft and will check for U joint phasing while I'm at it.
From research ford has had crappy drive shafts from 2000 onward.
I've also changed my carrier bearing to be shimmed from 1/4" to 11/2" and notice no difference still feel the shimmy/shudder starting around 90 km/h, even felt some around 60 km/h. Currently have 1 1/2" shim in there and the drive shaft is almost perfectly inline from the rear diff to the transfer case. But I think it's way too much. Going back down to 1/2".
Funny thing is that it has to be a harmonic imbalance induced somewhere in the system at those speeds. Funnier thing is its not felt during acceleration say but when you are at a constant speed and the torque would have no bearing on the axle flexing etc.
From research ford has had crappy drive shafts from 2000 onward.
I've also changed my carrier bearing to be shimmed from 1/4" to 11/2" and notice no difference still feel the shimmy/shudder starting around 90 km/h, even felt some around 60 km/h. Currently have 1 1/2" shim in there and the drive shaft is almost perfectly inline from the rear diff to the transfer case. But I think it's way too much. Going back down to 1/2".
Funny thing is that it has to be a harmonic imbalance induced somewhere in the system at those speeds. Funnier thing is its not felt during acceleration say but when you are at a constant speed and the torque would have no bearing on the axle flexing etc.
Last edited by winchested; 05-22-2015 at 09:26 AM.
05-22-2015, 11:55 AM
#5
Ford has some really smart people. They could fix it if they invested to do so. I have a feeling they know how to address it, it's just cost prohibitive to the business.
I haven't run across any OEM specification ranges for operating angles. They likely exist somewhere. In lieu of, I've been using the following operational setup standards from Dana/Spicer as a ball park. Figures 9 and 10 are most representative of our two-piece configuration. http://www2.dana.com/pdf/J3311-1-DSSP.pdf
My OEM measured angles the first shaft was positive .2 degrees and the pinion negative .5 degrees.
My modified non-loaded pinion angle with 2.5 degree angle shims installed the pinon is up 3.0 degrees. I got more adjustment swing out of the shims than anticipated. My first shaft out of the transfer case now measures is 1 degree positive. Thus I currently have a 2 degree disparity.
With the OEM setup on deceleration at 75 mph the oscillation gets worse. This tells me as the pinon is moved negative the symptom increases. Thus way I tried to bring the pinion positive ever so slightly.
I haven't run across any OEM specification ranges for operating angles. They likely exist somewhere. In lieu of, I've been using the following operational setup standards from Dana/Spicer as a ball park. Figures 9 and 10 are most representative of our two-piece configuration. http://www2.dana.com/pdf/J3311-1-DSSP.pdf
My OEM measured angles the first shaft was positive .2 degrees and the pinion negative .5 degrees.
My modified non-loaded pinion angle with 2.5 degree angle shims installed the pinon is up 3.0 degrees. I got more adjustment swing out of the shims than anticipated. My first shaft out of the transfer case now measures is 1 degree positive. Thus I currently have a 2 degree disparity.
With the OEM setup on deceleration at 75 mph the oscillation gets worse. This tells me as the pinon is moved negative the symptom increases. Thus way I tried to bring the pinion positive ever so slightly.
05-22-2015, 12:09 PM
#6
It's hard to fathom the intricacy involved. Even with everything in perfect balance, things can still vibrate. The angles involved without a double cardan U-joints cause the shaft to speed up and slow down during a single rotation of the drive shaft.
Driveline Angles
Driveline Phasing
Driveline Phasing
Proper phasing will only eliminate vibration if the driveline angles are correct.
Driveline Angles
Driveline Phasing
Driveline Phasing
Proper phasing will only eliminate vibration if the driveline angles are correct.
Last edited by joedotmac; 05-22-2015 at 12:13 PM.
05-22-2015, 12:17 PM
#7
Thank you for the info and videos. My pinion angle is positive on my truck, but I just noticed last week that it has factory 1" or so lift blocks on it. I'm going to look over the info you sent and get some shims and see what happens. Thanks again.
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05-22-2015, 04:24 PM
#8
Something I've overlooked.
The transfer case output housing isn't parallel to the ground. I'm measuring positive 3.8 degrees. Positive being the plane of the transfer case output shaft is higher in front, than on the rear. Since the first coupling shaft out of the transfer case measures 1 degree positive, this creates a 2.8 angle at the U-joint connected to the transfer case yoke. This angle is the inverse of any angles represented in the Spicer documentation. I'm not sure of the ramifications. Going to make a Visio diagram so its easily understandable.
The transfer case output housing isn't parallel to the ground. I'm measuring positive 3.8 degrees. Positive being the plane of the transfer case output shaft is higher in front, than on the rear. Since the first coupling shaft out of the transfer case measures 1 degree positive, this creates a 2.8 angle at the U-joint connected to the transfer case yoke. This angle is the inverse of any angles represented in the Spicer documentation. I'm not sure of the ramifications. Going to make a Visio diagram so its easily understandable.
05-22-2015, 10:03 PM
#9
OEM Measurements
Modified 1/4" carrier bearing shim, 2.5 degree pinion shims
Modified 1/4" carrier bearing shim, 2.5 degree pinion shims
Last edited by joedotmac; 05-23-2015 at 07:19 PM.