2004 Ranger Ext. Cab 4x4. 205,000 miles, 5 speed stick. Several months ago I began to experience a vibration, that I believe is coming from the rear driveshaft. My mechanic checked the universals and said they were fine. Tires balanced 5,000 miles ago, new front rotors-pads, greased slip yoke, new upper-lower ball joints, new front universal in front driveshaft, (mechanic said transfer case end universal was good). Still have the vibration, which is more noticeable when driveline is slack, (going downhill) and occurs around 68 mph. While checking rear driveshaft universals, I found that I can move the slip yoke up and down about 1/4" or more. Could a worn slip yoke cause this vibration. I have read this is a problem on high mileage trucks. Don't know what else to check.

 

Is it a steel driveshaft? I got a new steel 1-piece from ford and it comes with a blue plastic substance inside the female end of the slip yoke. My old driveshaft had completely destroyed this plastic coating over the years. It was vibrating from a dent though, so I don't know if this coating will allow enough slop to cause a vibration by itself. If you pull th driveshaft slip yoke boot off the two parts slide apart, and you can inspect the slip yoke. Mine had wads of plastic mashed into the bottom of the female end.

 

Aluminum driveshaft. Would it still have the same coating you describe on a steel driveshaft?

 

Different shafts will have different slip yokes sometimes so it's hard to say. If you have your driveshaft off pull the yoke apart and look inside, see if there's some blue plastic mashed in the bottom. If not, and if it seems tight, it's probably not your issue. While you have it apart, pack that yoke with grease and put it back together, wipe up the excess. If the vibrations go away you know it was partially the yoke. The grease isn't a permanent fix but it can keep it from vibrating for a few miles or a few weeks sometime.

 

Thanks HM. Will pull the driveshaft soon and check it.

 

I also have a vibration problem that has showed up in the last couple of thousand miles. (total mileage 154,000) This is a 2007 FX4 Level 2 vehicle, automatic. First of all there is a weird rhythmic sound near the back that sounds like a rock rattling in a can when you start out for a bit. Then, at say 50-70mph there is pretty bad vibration that is worse when I take my foot off the accelerator until it slows down enough. The vibration is still there even if I put it in neutral when doing those speeds.
I have had the wheels road force balanced and that did nothing.

Any ideas?

 

@Nucks you should have started your own thread,

But the vibration you are describing sounds like a bad U-Joint.

Set the parking brake or chock the wheels so truck can't move

Put transmission in neutral

Crawl underneath and see if you can get any movement from the U-Joints

 

Thanks! I will give that a try.

 

I cured my problem and it may apply to others I read about here. Pulled the slip-yoke apart and used break clean, screwdriver, rag etc. and clean about 8 oz. of grease out of the female end of the yoke. Amazing that I never thought of doing that when I greased the yoke. Vibration is gone.

 

I will give the yoke thing a try too. It is just about undrivable at highway speeds. Whole interior of cab is rattling.