U-Joint failure?

[RangerPilot]

So I got this "whomp...whomp...whomp" noise that increases with speed...starts to be noticable about 25 and isn't noticable above about 60. I have had the tires all balanced and replaced the front wheel bearings. It's the exact same.

I'm thinking it may be U-joints. The I can "feel" the noise in the floor of the truck, but not in the steering wheel.

We have the U-joints (Precision #354) in stock, and they're pretty cheap.

What you guys think...should I give it a shot?

 

[1985 Ford F-150]

Go under the truck and take all the load off the drive train and put it in neutral then shake the drive shaft and if it moves then theyre bad.

 

[RangerPilot]

Doesn't seem to move other than a slight wiggle. Doesn't seem unattached to the other mounting points for the joints.

 

[mrfixit]

Well, USUALLY, if they're bad, they're sloppy, true. But just because there's little-no play doesn't mean they are good.
Are they greaseable? if so, grease em up and see if they sound better. If they aren't greaseable, replace 'em anyway.
Get down next to the pinion on the differential- same scenario, blocked and in neutral, and give it a hefty push to test the pinion bearing. Also make sure the pumpkin's up on its lube.

 

[5.0]

The way I check u-joints... position the u-joint so that the cross is vertical and horizontal (like a + sign). Grab the drive shaft and push straight up toward the bed and pull down toward the ground. Rotate the shaft 90* and check again.

I haven't had much luck with spinning the shaft to detect a bad joint since the play in the differential makes it hard to tell what's really happening.

Do you have a carrier bearing?


.

 

[blacksnapon]

That kind of noise reminds me more of a cupped out tire. U-joints are closer to being a "harmonic" type of vibration. The tire can still be in balance. Think of balancing like taking an aspirin for a toothache.....you don't feel it, but the problem is still there.

 

[1985 Ford F-150]

Does the drive have a slip joint in it? If so check that to see if thats sloppy.

 

[mrfixit]

That kind of noise reminds me more of a cupped out tire. U-joints are closer to being a "harmonic" type of vibration. The tire can still be in balance. Think of balancing like taking an aspirin for a toothache.....you don't feel it, but the problem is still there.

Or even a separated belt, no? That was my first thought, but figured if he'd had them balanced, presumably it was someone looking close at the tire, lol...
But even as I write this, I hear that inner VINCE in my head saying, "Presume NOTHING!"

 

[john112deere]

It's kinda imprecise...but a friend's Ranger had a noise that I thought might be the u-joints.

I crawled under and "whapped" the driveshaft with the heel of my hand, hard, and paid attention to how it sounded. Then I crawled under my truck and did the same thing. His sounded "looser/sloppier" than mine, by a lot, and sure enough, new u-joints fixed it.

 

[RangerPilot]

Alright I'll smack the hell outta the driveshaft tomorrow Ian...a guy at work drives a Ranger, I'm sure he'll let me smack it as well.

No carrier bearing.

I'll also try the push, 90, push method. May just replace them anyways (they're less than $25 together).

The tire thing genuinely worries me...as all I can imagine is a tire giving out at 70 going to/from Dallas. I guess I could yank them one at a time and swap the spare around to see if the noise goes away.