Mechanic Ear Needed: What is this sound on my truck?

[Dale Moser]

I always take the drive shaft to an auto supply and have them press new ones in, but they are getting hard to find.

American Drive Shaft & Gear will do it while you wait, they are down off Sylvania, around Long Ave. Old school driveline shop, they have helped me out with several tricky jobs over the years.

[Dale Moser]

DON'T FORGET TO BLOCK THE TIRES UP WELL BEFORE YOU TAKE THAT DRIVESHAFT OUT!!! "Park" no longer works at that point, and she will run off on you.

[Traildust]

U joint for sure. Just replace them all at once. They all have the same miles on them.

Rat here!

[CDF]

Thats a siezed up u-joint. Replace them all

[Sethmac]

Was curious and chocked the wheels and jacked up the rear end...put it in neutral and inspected each u-joint...back one had no play...

Front one on the other hand has all kinds of lateral play when orienting one way. Figuring that is the culprit. Was even able to coax a little squeak out of it.

[RifleBowPistol]

Probably U-joint. Just because that rear joint does not have play, don't assume it's good. Often they get bound up. The best way to check u-joints, is to pull the drive shaft and check their movement out of the vehicle. Either slack in the U-joint or a stiff/hard to rotate joint, would be bad.

[twistedmidnite]

U joint

[Hollywood]

If you have never installed U joints ( especially in an aluminum driveshaft ) take Dales advise & have them installed for you. Fairly easy if you have the right tools & a vise. Be sure to grease output splines on that transmission yoke while you have the d/s out.

[Big Lee]

If you have never installed U joints ( especially in an aluminum driveshaft ) take Dales advise & have them installed for you. Fairly easy if you have the right tools & a vise. Be sure to grease output splines on that transmission yoke while you have the d/s out.

This. You can use a little Vaseline on the splines on the yoke.

[sasqy]

DON'T FORGET TO BLOCK THE TIRES UP WELL BEFORE YOU TAKE THAT DRIVESHAFT OUT!!! "Park" no longer works at that point, and she will run off on you.

Good advice here !
My Bro. In law sat with his Ford LTD on his chest for 2 hrs before someone came hone and helped him.
Thank Goodness he was skinny as a rail.

[Sethmac]

Pulled the drive shaft, pressed out u joints (culprit was bone dry). Pressed back in one side before I ran out of light (and steam). Hopefully tomorrow

[Sethmac]

Job finished on the 23rd..picture of the no longer round culprit

[Randy]

I had a hotrod square body in highschool that used to break and eat ujoints. Know that sound you had well.

[easeup]

that is the smoking gun

[UncleBubba]

that is the smoking gun

Yes, OP you are lucky.