Driveshaft questions.

[DocVijay]

After lifting my X, there is a big vibration at about 30mph it only lasts for a few seconds. It's independent of engine speed, as it happens in any gear at 30 mph. I think it's the driveshaft. At the front, where it enters the tranny, there is about an inch (maybe a bit more) of shiny metal thet used to be inside the tranny. Now it's exposed. Could this be the problem, that there is too much play between them?

Now, where can I get an aluminum driveshaft from? Ford Racing has one for the Mustang. If it's the right length, could I use this? Also, how is the driveshaft measured? The Ford Racing one is 45.5" long. Do they make custom lengths? Also, I read in another post about the Ranger having an aluminum driveshaft available. As they X and Ranger are similar, would this oone work?

 

[Stephen S]

I would suspect the vibration is from the driveshaft as a result of your lift. The 1 inch of shiny metal you see is there because the rear axle was moved farther away from the truck. This pulls the driveshaft out of the tranny a bit to make up for the movement (it's normal operation of the slip yoke). Since you have a Sport, the driveshaft is already short and the increased angles at the end of the tranny and where it enters the rear diff may be contributing to your vibration. I believe Taxxman had the same problems when he installed his 4" Superlift kit. If I remember right, the fix for him was to angle the rear diff a little more towards the tranny (using shims) to decrease the angles on the u-joints. If you can find the thread, it might be helpful.

 

[DB_1]

From what i've been told your driveshaft angle and your pinion angle (the yoke on the differential) should be within one degree of eachother to avoid vibration. You can measure it with an angle finder by putting it on the driveshaft, get your reading, then measure the pinion angle then see what the difference is.

 

[Harry5150]

Could also be the tires. My 33's vibrate a lot below 20 mph ( the most below 10 mph) but kinda diminsh with increase in speed.

I've also noticed that the tires vibrate the truck when making u-turns or almost full lock turns.

When I'm at crusing speeds on the freeway the tires make a lot of noise / vibrate but when I hit a slight dip and then come out of it (not catching air), un-weighting the tire make less noise / vibration leading me to belive that the tires were the source of vibration.

As my torsions have sagged creating additional negative camber, the tire noise/vibrations have increased some.

 

[DocVijay]

I don't think it's the tires. First of all it doesn't "feel" like the tires making noise. Also, and more imortnantly, I jacked up the back and tried it and it still made the noise/vibration.

I'm going to look into jsut getting a longer driveshaft. I know that the stock one is too short, as I can see shiny bits that weren't there before. So why not. Besides, If if get an aluminum one, it'll be about 30% lighter, which means more hp!

 

[Harry5150]

I had a concern about the shaft poping out if I caught some air but it hasn't happend yet. Let us know how much it costs to have it retubed.

I have a lot of shiny drive shaft showing and I think it's putting some stress on the tailshaft oil seal. I have a little leakaged now from it.

 

[DocVijay]

Originally posted by Harry5150
I had a concern about the shaft poping out if I caught some air but it hasn't happend yet. Let us know how much it costs to have it retubed.

I have a lot of shiny drive shaft showing and I think it's putting some stress on the tailshaft oil seal. I have a little leakaged now from it.

While I am somewhat concerned about the driveshaft popping out on me, I'm much more concerened about putting additional stress on the drivetrain. I don't want the driveshaft to vibrate too much and shake other things to pieces. I still spend 80% of driving on-road, so catching air is not too much of an issue.

Besides, an ounce of prevention is worth a pound of cure. I figure I might as well just do it now just in case it would have broken more stuff in the future.