Yesterday, I just started hearing a chattering metallic sound (seemingly from the underside of my truck) whose pitch and frequency coincides with my acceleration. I don't hear it when cruising or braking. There is no clunking or vibrating, and everything feels solid and runs well.

I checked each U-joint, front and back one at at time, by putting the manual transmission in gear, and twisting the drive shaft by hand, while trying to hold steady the other part connecting to the U-joint.
I detected no play in either U-joint.

I also checked for play by putting a pry bar where the U-joints connect and twisting in every possible direction. Again, no play.

Could this be the early sound of a U-joint that soon will need replacing? Maybe a bearing which has lost its lubrication?

Thanks in advance for anyone sharing their previous experience.

 

Sounds more like a bearing to me, but you could grease up the U-joints, that's never going to hurt.

 

Thanks, Encho:

Maybe the U-joint bushings? I'll try to squirt a little grease in there first and see what happens.

 

Sounds like a dry u-joint that has not come apart YET.. If the joints have grease fittings you can pump a little grease in them and try it, if the noise goes away it was dry.. If there are no fittings you might look for signs of rust at the seal area of the u-joint bearing caps..

My experience has been when they squeak, they are asking for a replacement..

 

If that is so, don't wait for the U-joint to fail, replace it ASAP, the same with bearings, when you let any of those fails it usually leads to more expensive repairs.

 

Thanks White97 xlt:
That's what I was wondering, if there are grease fittings. I didn't notice any last night when I was checking for play. I'll check the bearing caps like you suggest.

Yeah, they're squeaking, which I guess is just a prelude to the rattling and clunking stage. In past vehicles, I only remember the rattling and clunking stage. It seems like for the last couple months, I've had about one new problem per week. Welcome to the club, I guess. U-joint disassembly/assembly and/or replacement has been straight forward in my experience ('72 Buick Skylark and '69 Pontiac GTO), but we'll see. :-)

 

I think I would just go ahead and replace the U-Joints and see if the squeak goes away. They are cheap and easy to replace, plus you then know you have good U-Joints. Who knows how long those old ones have been in there. Since they don't have grease zerks on them, it's possible they are original.

I have had U-Joints start to squeak like that before having any noticeable play in them.

 

Thanks kd0axs and Encho:
You're right, of course. I'm sure they are original and I have > 130,000 miles. It's an easy fix. I'm hitting the parts store on the way home today. I've been reading a little, and there are serveral things that could have failed, e.g. needle bearing, c-ring, which could eventually ruin a yoke or worse. I think the bearings come in the kit.
I'll post the results. Thanks, again.

 

Search for the ones with grease fittings (Spicer is a great choice), you will be able to lube/do maintenance to them, this will prevent them to dry and fail for a long time.

 

Thanks, Encho: I'll ask for them.

 

I just did the u joints in my truck and van. I kept hearing clunking. I was checking them in gear and didn't see any play. Someone on here suggested checking them in neutral. Thats when I could see the play. I guess in gear theres pressure on them and they won't move either way.

When I changed them 4 cups out of 8 didn't have any needle bearings left in my van. 1 out of 12 didn't have any left in my truck. Narrowly avoided disaster there. Even if they don't have play in them I'd do them anyway. It was my first time doing them and it was about as easy as it gets.

 

correct, you need to be in nuetral

 

Thanks, redrivergorge: Yeah, dropping the driveshaft and removing the u-joints was easy with a vise and sockets, but I was having a hard time pressing the new ones in using the same tools. I think I was having a bearing cap alignment issue, and couldn't get the bearing caps to go in (I was careful that the needle bearings were in place), so I dropped the stuff off at a good local mechanic who has a press and will do it for me for a few bucks. Reinstalling the drive shaft assembly should be smooth. I was careful to mark the mating parts with chalk for alignment.

 

Ive had problems with reinstallation myself...what usually happens is, a needle bearing or two will get jarred into the bottom of the cup while trying to get the second side in...you can't really tell until both sides are seated and the clip won't fit the groove...take it apart and repeat...

I found that a good coating of heavy grease pressed around the bearings helps to hold them to the sides of the cup during assembly....also, a rag wedged between the yoke and the u-joint helps control spacing while you drive the cups in...

 

I put a little grease around the outside of the cup on mine. They slid right in with a C-clamp. Maybe thats a bad idea I don't know thats what my dad told me they used to do.

On my truck the 2 cups that go on the u bolts were slightly bigger than the ones that went to the drive shaft. I barely noticed myself I could see that making them hard to get back in.

The u joints I got were pre-greased I dropped one of the cups and the needle bearings still didn't move.