Ford Power Stroke Nation banner

Rear Axle Vibration???

75K views 43 replies 14 participants last post by  1970something 
#1 ·
Here is the background...2003 F250 Supercab 7.3 PSD, I have had a vibration that feels like it is coming from the rear. I have had the tires road force balanced and rotated with no effect. I replaced the carrier bearing and all the U-Joints with no effect. I have tried balancing the driveshaft with hose clamps per the Ford tech article with minimal effect. I just replaced the fluid in the rear axle and everything looked fine...no metal shavings, no movement in the pinion gear or carrier assembly. There was some movement in the spider gears for the trac loc. The axle bearings have maybe an 1/8" of play. I just checked the ebrake cables and calipers and the only thing that was stiff was the two lower sliders on each side of the caliper...I greased those and am heading out for a test ride. The only unusual thing is there was differential fluid slowly leaking around the pinion flange and out of the bottom of the cover. When I went to loosen the lug nuts while on jack stands on the driver side the tac loc held the wheels, when I moved to the other side the wheels started spinning in opposite directions as soon as I started turning the wrench. I went back and started tightening the drivers side and the trac loc held for three lug nuts and then started spinning in the opposite direction as the other wheel??? Is the trac loc shot and causing the vibrations? Any help is appreciated
 
#2 ·
Well after a test drive, the traction loc is shot....Did a burnout and only on wheel spun. No change with the vibration. I have also noticed that first thing in the morning or after the truck has cooled off the vibration doesn't start for about ten miles....then it seems the further you drive the worse it gets. It oscillates when it starts and by that I mean it is smooth for a half mile and then it starts and gets progressively worse for a mile and a half and then smooths out again. It repeats that cycle and the vibration gets worse the faster I go. Any help is appreciated.
 
#5 ·
Have you checked the axles to see if one is bent? It can happen that is my thought. Also does it vibrate on the coast side?
 
#6 ·
I have not checked for a bent axle yet...I do all street driving so it didnt cross my mind. Just some more info on the nature of the vibration...it is really pronounced at 45-50mph hot or cold, and happens while driving, coasting, and decelerating. Occasionally I can feel it in the steering wheel. Any thoughts on where else to look?
 
#7 ·
I suspect the limit slip is somehow chattering.

I've got 2 Superduties ('99 F250 and 08 F350) and both of them do this. You might try adding a bit more friction modifier to your diff.

The other thing to check out is the carrier bearing, if your truck has one. The rubber isolator can be dried out.
 
#8 ·
I didnt think about the friction modifier....I had bought 4oz of it and had not put it in yet while I was checking the traction loc. I will put it in and see if it makes a difference. I replaced the carrier bearing when I replaced the ujoints so I don't think it is the issue. I also cant tell if it is my imagination or not but on the highway if I enter a sweeping turn to the right it seems to make it vibrate....but only occasionally. I will try the friction modifier and report back...
 
#11 ·
Does anyone know the acceptable runout on axle flanges? I placed a dial indicator on the outside edge of the hub with the wheels on and found the right hub has .035" of vertical travel and the left has 0.15". I pushed and pulled on the wheels to check the bearings and the left had a little wiggle but nothing from the right. I am sure the right axle is causing the majority of the issue. I know the bearings or bent axle can cause this runout....can a worn carrier bearing do it as well??
 
#14 ·
I'm watching this thread. I'm hoping you find the issue. I'm going to check my trucks for whatever you find wrong with yours.
 
#18 ·
08 shop manual, 10.5 diff section, vibration troubleshooting sends you to section 100, where they want you to measure the frequency of the vibration and then do a bunch of calc to determine the tire, driveshaft and engine frequencies and harmonics thereof and then compare to see what matches up.

In the diff section, it says that if wheelbearings are a problem, you'll get louder noise in turns.

Under driveshaft troubleshooting, it has different things possible for different orders of vibration.

First Order- driveshaft, pinion gear, pinion bearing.

Second Order- U joint, Output shaft bushing in transmission.

Third Order - Axle shaft, Ring gear.

Section 205. Driveline Vibration at cruising speeds.

Causes.
- worn U Joints
- worn carrier bearing support
- loose axle pinion flange bolts
- excessive axle pinion flange runout
- Driveshaft is out of balance
- Excessive driveshaft runout
- Driveline angles out of spec

There is quite a bit of material on each of these topics. I don't know where to start explaining.
 
#19 ·
That is alot of info....I checked the output flange at the the transmission and there is quite a bit of rotational play and a little up and down play. I am not sure how much play there should be. I know that .035 is way out of round and should cause one heck of a vibration I am just trying to source why it is so far out. I am leaning toward balancing the driveshaft, replacing the rear axle bearings, replacing the rear shocks, and replacing the tires as they are getting pretty low on tread and after several thousand miles of out of round I cant imagine they would ride smooth. I will update as I repair.
 
#20 ·
The spec on the flange run out (on the diameter) is 10 thou, but Ford uses a special plate attached to the flange to do the measuring. Its in section 205-00-15.

If I were you, I'd buy a shop manual before I went any further.
 
#21 ·
Did it list the possible causes for excessive axle flange runout? I pulled the axles and there is play in the bearings on both sides. Not excessive but they will still move. I checked the runout again using the same setup of the dial indicator on a magnetic mount on a flat piece of steel sitting on the garage floor. The indicator is then set against the bottom edge of the flange and the wheel was rotated. This time I got almost .045 of runout on the right side? The only thing I can think of that would cause that much runout is worn axle bearings.
 
#22 ·
I forget and I'm on the road for the next few days. I'll reply when I get back home.
 
#23 ·
Update...So I replace the outer rear wheel bearings as that was all the parts housees carried, the inners are special order only at all of them. It definately tightened up the rear but made the vibration way worse. I repacked the front bearings due to a noise that I thought had been coming from the front and it made no difference. At highway speeds it sounds like a bearing noise coming from the transmission tunnel area. When I got home I had it in park and revved the engine up to about 1250rpm there was the same vibration I had been feeling at 50mph. Can a bad torque converter cause all these issues?
 
#25 ·
There is another thread on here with guys having the same issue. One of them thought there converter was bad like you are. They replaced there clutch fan and the vibration went away. Could be your problem since it is doing it in park.
 
#26 ·
Thats funny....I was just checking things over today and noticed a slight wobble in the fan. I wiggled it and there is a little play in it. The wierd thing is that in park at 2200 rpm little vibration. At highway speed and 75-80mph it feels like the truck is gonna shake apart and there is a loud bearing sound coming from the area around the transmission tunnel. If I put it in neutral and the vibration gets better and the bearing noise goes away. I also noticed a shudder upon acceleration and decceleration......I am at a loss??
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top