Lining up driveshaft

[69rangerman]

Dealing with what I suspect is a mild but persistent driveshaft noise.

Are there basically only 2 ways to line up a driveshaft (2 pc) I can only flip it 180 degrees right?

Took the truck on a 80 mile work related trip tonight and the whine/drone that comes in at 40 is louder than anything else. Much more noticable when I let off the gas and disappears below 20.

Thinking about flipping it tonight.

Thanks

[fordman]

before you do anything to it. grab the driveshaft with the truck in park and see if you can turn it in either direction back and forth. if it makes a knock or noise it could be a bad ujoint. do that test to both halfs. if no noise is heard you could try flipping it 180.

[69rangerman]

Thanks fordman, I was just looking for an excuse to get my wrenches dirty - I'm on my way.

[72hiboy4x4]

sounds kinds like a bad pinion bearing or axle bearing to me.
A driveshaft thats out of phase will vibrate, not howl/hum.

another thought, did you change the tires recently? an aggressive tire will howl like that also.

[fordman]

i think he is hooked on bumps.

[69rangerman]

Well, Not sure what I've done until I drive it tomorrow but there was a little stuck on weight on both pcs of drive shaft. Don't know if they were lined up or opposite to begin with but I decided to oppose them just in case they were intended to cancel each other out.

Guy at work thought it might be in the diff also.

On a related note..when I dropped the rear driveshaft and was able to turn the front shaft freely, I noticed that when I turned it in the Drive direction it had this weak sort of sqeak/sqeal sound that seemed to be coming from the tail cone or the tranny.

[fordman]

could be the new seal? or a dry ujoint at the end of the tailhousing.

[390Nut]

Always, ALWAYS, put the driveshaft back together the way it came apart. The two-piece driveshafts are balanced as a unit, and you are very likely out of balance now.

Keep driving it that way, and you'll slowly destroy your trans output shaft seal, your rear axle pinion seal, or both, not to mention possible damage to the splines on the output shaft or pinion yoke.

You can do one of two things to correct the situation. Keep changing the driveline orientation (pulling it apart and moving it one spline at a time) till you think you've got it right, and hope that you DO, or pony up and get it rebalanced properly at a driveline shop.

[lightning_msd]

this brings a funny yet scary story in my mind. my dad (typical redneck) was towing the 78 f150 ranch truck when the axle bearing gave in, we towed it about 8 miles and then we felt a nice nudge sitting in the chebby tahoe i looked behind us and i saw an axle rolling in the ditch and perfectly hopped a barbwire fence and went on a few more yards. just goes to show, that ford did not want to be pulled by a chev. before that bearing went tho it was a lotta grinding and moaning and humming sounds. i would check both bearings if i were you. sounds a lot like the problem. good luck 69

[FORDification]

Well, one thing you need to be aware of is that with a 2-piece driveshaft, it's possible to assemble the driveshafts 'out-of-phase'. Your driveshafts will be phased properly when one U-joint is positioned so that there's a top, left, right, and bottom cap, the other one in an identical position. Both yokes need to be be in the same plane. If the second U-joint is installed out of phase, like maybe pointing out at a 45-degree angle when compared to the first, it'll often cause a vibration that's hard to track down and could also cause some binding in the driveline.

From the factory shop manual:

[390Nut]

Thanks Keith, I had completely forgot about that. One of those things so ingrained I dont think about it anymore.

Makes it much easier to find the balance of the driveline, you only need to take it apart 3 times (at most)

[69rangerman]

Thanks Keith,

I went for a drive tonight after switching the shafts around and it's better but still there so I'll try the diagram approach.

By the way, would it matter if I was unable to get the carrier bearing completely seated agains the step in the front shaft?

Thanks

[69rangerman]

Well, at least I'm not afraid of the driveshaft anymore - dropped it 4 times over the weekend. I've lined the yokes up one way and then again 180 degrees. It's not as bad as when I first posted but still noticeable.

Does it matter which way the support bearing faces?

I guess I'm trying to eliminate the driveshaft as the problem before yanking axles etc. Should I begin just going around the clock one tooth at a time?

Thanks

[fordman]

your carrier bearing should have been pressed on with a press. i think it does matter wqhich way it goes on but i am not sure. as far as being one tooth off on the splines i dont think so. line up the ujoints as above. i have never worried about how they came off or went back on as long as the ujoints lined up . i haven't had a problem so far. no noise or anything.

[ICEMAN6166]

i had a noise that i thought was from the transfer case, turned out my 4x4s front driveshaft was bad,yoke and slip end were loose, not real sloppy but even after greasing did not improve so i bought an NOS shaft and a NOS yoke on evilbay, both had arrows on them notating the correct orientation.lined up the arrows and installed it and no longer any noise.