Bad Vibrations
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Joined: May 2005
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Bad Vibrations
Hey Guys. I Got A 2004 F150 And Had It Lifted And Its Great But Now I Notice A Vibration When I Put It Into 4x4. I Didn't Think Anything Of It But The Vibration Is Horrible. It Starts At 15km And You Can Still Feel It At 80km But Not As Bad. The Vibrations Are Horrible In High And Low Speeds But Only When I Engage In 4x Hi. In Two Wheel Drive There Is No Vibration. Took It To Mech And They Said Maybe Ujoint Or Transfer Case. Took It To Ford They Replaced Ujoint And They Said It Was The Angle Drive Shafts. Other Mechanincs Disagree. Tech At Ford Told Me On The Side He Figures Transfer Case As Well. Ford Told Me The Angle Of Driveshafts Was Off Tha**** Suppose To Be At4 And Mines An 8. Please Help I Need To Get Some Answers As Fors Says Go Back To Where You Got It Lifted And That Shop Says Go To Ford. Please Help
Senior Member
Joined: Jul 2000
Posts: 541
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From: Indianapolis, IN USA
Lesson on Driveline Angularity
There is almost nothing more beautiful than good looking lifted truck or SUV.
Many problem can arise when lifting a vehicle. The most common seems to be the driveline angularity. As a certified driveline technician, I have seen many abortions over the years. Yes, one was in a movie a few years back (cant remember the name of the movie).
The main concern on driveling angularity is the difference in operating angle of u-joint "A" and u-joint "B". How do I find this out and how to correct it?
Attain a spirit filled (liquid) protractor (usually available at Sears, Wal-Mart, or the local hardware). Put it on the D/S & measure the angle of the tubing at 12 o' clock (toward the vehicle floor board). Next measure the degree angle of each yoke on the flat (clock d/s to have flat ear of the yoke towards the floorboard of the vehicle).
Next: take the d/s tubing angle minus the u-joint angle "A" and then d/s tubing angle minus "B". the difference is the operating angle between u-joint "A" & "B".
For example: Let's say your reading @ the tran. is -3 deg., the angle at the diff. is +3 degrees and the angle on the tubing was 8 degrees. 8-3=0 and 8-3=0. You're difference in operating angle of the u-joints would be zero (don't worry about negatives and positives, they cancel out).
Zero difference in operating angle on u-joints is bad; it will brinnell the cross (trunion) of the u-joint. More than 2 degrees will generally destroy many components in the vehicle driveline, cab, and body, due to the vibration. Ideally, you want a minimum of 1/2 degree and no more than 1.5 degree difference in operating angle of u-joint "A" and u-joint 'B".
To obtain the correct operating angle, you may have to loosen the spring mountings and slide wedge shims under the axle mounting pads, checking and readjusting is usually required several times to get the assembly within tolerance.
Many problem can arise when lifting a vehicle. The most common seems to be the driveline angularity. As a certified driveline technician, I have seen many abortions over the years. Yes, one was in a movie a few years back (cant remember the name of the movie).
The main concern on driveling angularity is the difference in operating angle of u-joint "A" and u-joint "B". How do I find this out and how to correct it?
Attain a spirit filled (liquid) protractor (usually available at Sears, Wal-Mart, or the local hardware). Put it on the D/S & measure the angle of the tubing at 12 o' clock (toward the vehicle floor board). Next measure the degree angle of each yoke on the flat (clock d/s to have flat ear of the yoke towards the floorboard of the vehicle).
Next: take the d/s tubing angle minus the u-joint angle "A" and then d/s tubing angle minus "B". the difference is the operating angle between u-joint "A" & "B".
For example: Let's say your reading @ the tran. is -3 deg., the angle at the diff. is +3 degrees and the angle on the tubing was 8 degrees. 8-3=0 and 8-3=0. You're difference in operating angle of the u-joints would be zero (don't worry about negatives and positives, they cancel out).
Zero difference in operating angle on u-joints is bad; it will brinnell the cross (trunion) of the u-joint. More than 2 degrees will generally destroy many components in the vehicle driveline, cab, and body, due to the vibration. Ideally, you want a minimum of 1/2 degree and no more than 1.5 degree difference in operating angle of u-joint "A" and u-joint 'B".
To obtain the correct operating angle, you may have to loosen the spring mountings and slide wedge shims under the axle mounting pads, checking and readjusting is usually required several times to get the assembly within tolerance.