Weird ticking noise

Hey guys...need some help here. '99 2.7L 4cyl.

I have a ticking noise that corresponds to the RPM.

It happens only when I'm accelerating. It sounds like it's coming from underneath the truck (not the engine compartment.)

I hear it most often when turning from a stop sign, but also if I am going up a steep hill, or speeding up to get on a highway.

It stops once I hit 30-40mph out of a stop sign, or once I stop accelerating on a hill or on-ramp...no real correlation to speed.

I put my truck up on jack stands and I could not replicate the sound...so the wheels making contact with the road has something to do with it.

It's a really ugly sound...like if instead of putting baseball cards in your bicycle spokes you put a piece of metal.

Hopefully this is a decent description...you guys have been really helpful to me in the past so I appreciate any input.

Thanks.

 

It corresponds with RPMs but isn't coming from the engine compartment? That's odd. I would say CV axle but you said RPMs and not relative speed.

 

Put a load on engine with the brakes when you put it on jackstands. Have a buddy carefully listen and find the noise if it makes it. CAREFULLY!

 

Ok, thanks Devinzz I will try that right now.

Thunderone, I do not think it is the cv axle as the noise appears to be coming rear. My truck is RWD and there a straight shot to the rear wheels from the differential...no CV axle.

Thanks for the help so far...much appreciated

 

Rocks in your tire tread? Huge annoyance for me but unavoidable

 

Another description of the sound would be that it sounds like there were pebbles in my tires and they're flying out and hitting the truck...except there are no pebbles in my tires, so...

 

Unavoidable for me as well...so that was my first thought of what it was. But I know that's not it, as my treads are clear right now.

 

sounds like your u-joints are going out on your driveshaft. check for play and wear around there.

 

The rear ujoint is completely dry and beginning to rust...no grease at all. The ones in the front look very healthy.

The one in the rear has no zerk fitting so I can't lube it up. I think it is worth replacing since I know it's not too difficult of a job...and hopefully that will be the end of the problem.

Thanks

 

no problem. i chased what sounds like it is the same noise for about a month on my last truck before finding it. at lease ujoints are cheap and easy to replace.

 

Before you just go replacing things, just check them for play. Push it side to side and up and down and see if it's loose, and make sure the "looseness" you are feeling isn't coming from the carrier bearing.

 

Is your truck a 5 speed or auto? If it's an auto than I would remove the bell housing inspection plate and check the flexplate for cracks. Under acceleration it will flex the crack and can contact the engine block as it rotates. If this is happening you will see scrape marks on the block by shining a flashlight up through the inspection plate opening.

 

I changed the u-joint and it seems to have fixed the problem. I'll know for sure after a longer drive.

There was no play at all in the u-joint I took out...totally stuck in place from lack of lube. It had a zerk but it was between the yokes and so inaccessible with a grease gun. The one I replaced it with is of better quality overall but also has an accessible zerk.

I had to use an angle grinder to cut the old one out...which was a real treat making sure to not slice up the yokes in the process.

Thanks again for everyone's help.

 

It is an auto. Even if the noise doesn't come back I think I'll do this anyway just to have a look. Sounds like good maintenance.

Thanks