broke something???

[HARDTRAILZ]

I have been chasing a sound for a couple weeks now in the drivetrain of my truck. It is hard to explain and it is baffling me. I will share what I have done and tried and maybe someone can help shed some light.

The sound is like rocks in a can or a metal tapping, but it is not always there. Some days it is all the time I drive and others occasional or not at all. Cant find a driver inducing action to force it to happen everything. It has gotten progressively worse. It is however induced by motion and throttle. No noise when the truck is not in drive or reverse. At take off it makes noise while you are on the throttle and the noise will reduce or go away when off the throttle, but will sometimes reappear when braking, but not always.
Sound seems to come from TC, but while out of truck with it on stands and thottle being given it seems to come from driveshaft. But last week i could have sworn it was in the front diff.m Also have had a slight whine/howl when driing for the past few months, but the rear diff looked good when I popped the cover and it it didnt really affect anything. New noise makes me thing failure is coming.

What I have done... I changed TC and diff fluids....no help. I thought it was front diff since when the DR tire is off if io spin the half shaft about once every rotation it seems to grab the front drveshaft and move it a bit. Front diff had light metallic to the fluid but no chunks. TC fluid looked good. Rear was watery, but that makes sense with what I do with the truck.

I still was thinking front diff, so I pulled the dr half shaft and it changed nothing. I did notice that the front draveshaft spin when the truck moves though, but can be stopped by hand and can be freely rotated either way. Currently dr shaft is out and milk cap covering diff hole. A peek in the hole shows no chunks or broken pieces like I expected.

I then thought TC since when I grab the front shaft it seems to move more than I thought and makes some noise, but the neighbors stock TB has same movement and sound when I crawled under it. I put the rearend on jack stands and blocked front tires. Check rear driveshaft, Feels pretty good, maybe a minimal amount of play in the pinion and slightly less play in TC side. I put truck in nuetral and have some one spin tire while I hold driveshaft and the driveshaft seems to want to spin and like the rear is kinda grabbing it, but no noise. Then try starting truck with rear in air and when I rev the motor in D the sound is there. Seems to comes from driveshaft. But also seems that rearend is not acting right, may have been my head. Also seems that more noise from TC than rearend. I try and try to pinpoint sound, but cant so I crack open the poumpkin epecting parts and find nothing, to metal bits, no chipped teeth, just looks like it always has. Spin tires with cover off and diff seems fine. I have pics if anyone wants to see.

So my guesses...u-joints and or rear wheel bearings, but the noise sounds like broken pieces in a diff or something. The transfer case went in and out of 4x4 fine before the issue and again this week including right before tear-down.

Currently it is on jackstands under rear axle and minus the dr half shaft. If you have anything for me to try. Any and all help is appreciated. I talked with Barton and Regulator and ?????...no one knows. Kinda stuck unless I start tossing parts at it.

[fishsticks]

Pull the rear driveshaft out. Run the truck. No noise? Great, you've eliminated the rear output of the TC (for the most part).

Shake the driveshaft. Anything inside?

In my experience, bad rear wheel bearings have a vibration associated with them.

IMO change out the U joints while you have the D/S out. Get the type that you don't have to torch out. I need to do this as well.

[HARDTRAILZ]

Driveshaft is gonna be pulled but it literally started hailing as I washing my hands from pulling diff cover. Figured it would have to wait.

[fishsticks]

Might start looking for an 8.6"... assuming you eliminate other possibilities. If I could find as cheap one I'd do that rather than bother with whatever is wrong with your current rear axle.

[HARDTRAILZ]

The rearend looks good. It feels tight and looks like it spins good. No pieces cracks or wear showing. I would probably go stronger than an 8.6 if I change the rear.

I would post the gear pics but my phone and I don't know how to work together on that.

Plus finding a newer 8.6 isn't cheap or easy around here. Older is easy but if I am gonna lose tc and stab trac than 14 bolt or 60 seems like a better idea for the long term.

[fishsticks]

How about a 9.5" 14bolt out of a wrecked SS? Correct width and no need to weld the 5 link stuff onto it.

[HARDTRAILZ]

Or the locked 14 I have and then use the matching 44 in the front....

[fishsticks]

Or the locked 14 I have and then use the matching 44 in the front....

Pfft...

[Trail X]

Chasing down funny sounds is always tricky. I've chased down two on my truck so far. One ended up being the crushed bearing in the front disconnect, and the other ended up being a silly piece of metal that got bent and was rubbing on my LCA (I was convinced that it was my tie rods).

Anyways... when you said rocks in a tin can... I immediately thought of the exhaust. Have you inspected that to see if the noise is coming from there? You said it was throttle induced... does that mean revving in neutral never makes the sound? Maybe there is a heat shield that's vibrating? I'll bet that when you find the source, it will be one of those... oh! just that?

The whine during the past few months may not be related to the other noise. When you said you had movement in the pinion of the rear end, that could be an issue. However everything else you said sounded pretty normal. I don't believe pinions should have any motion due to the way their bearings work.

Anyways, that's my quick takeaway from your post.

[fishsticks]

I don't believe pinions should have any motion due to the way their bearings work.

The pinion should have a slight amount of rotational lash but shouldn't move in and out. When I did my rear gears I didn't seat the pinion bearing all the way initially. That caused mine to loosen up and whine on deceleration.

[Trail X]

I don't believe pinions should have any motion due to the way their bearings work.

The pinion should have a slight amount of rotational lash but shouldn't move in and out. When I did my rear gears I didn't seat the pinion bearing all the way initially. That caused mine to loosen up and whine on deceleration.

Right, only rotational lash, as that's just the clearance between the gear teeth. Moving in and out or up and down at all could indicate an issue.

[HARDTRAILZ]

Can't get the sound without the wheels turning. I had my exhaust done about a year ago and it looks good. I think I tried moving everything and the driveshafts are about all that has any movement.

The pinion movement is not in and out but slight wiggle..I thought about tightening it up when driveshaft is out. The whine was mostly accel not off throttle or decel.

[bartonmd]

It should also be noted that the noise almost completely went away when in 4WD...

Mike

[HARDTRAILZ]

Yep. It did at first, but now it doesn't go away as much in 4x4.

[fishsticks]

It should also be noted that the noise almost completely went away when in 4WD...

Mike

Interesting... that makes me think TC. Is it possible to shatter a clutch in these things? That would make the noise but not necessarily blacken the fluid immediately.

[HARDTRAILZ]

Other than for testing purposes after the noise got bad it had not been in 4x4 since begin of January.

I thought front output but it moves and sounds like factory one next door. Rear output is not as loose as front.

[bartonmd]

So it didn't go away as much when you put it in 4WD, recently, before taking any half shafts out? If it was after a half shaft came out, I would say that you basically weren't in 4WD, because the front end wasn't loaded, because there was no driver side shaft in it...

Mike

[HARDTRAILZ]

Never tried 4x4 after removing halfshaft. Noise was still there. I can hold front driveshaft still and get noise when rear spins

When noise initially started 4x4 would almost eliminate sound but not completely. Now when I did 4x4 yesterday the sound was slightly less but not by much.

[dirty anton]

hey have you tried putting it in neutral while driving to see if noise goes away. i had the exact same sound once in a while. then tranny had to be rebuilt several months later.

[HARDTRAILZ]

I want to say I tried that and it didn't make much or any difference but maybe I only thought about trying it. Tried alot of things and it all runs together at this point.