Need Help with Popping Noise!!

[Pstyckiewicz]

So my truck developed a rather loud binding popping noise.
Back ground- drove the truck a few weeks ago on the highway and melted a fork in the transfer case. Drained oil- only had about a cup of oil in there, plus the pin was missing on the shifter fork. Fixed that cleaned it up put it back in there. Drives normal, shifts into each mode on transfer case fine. Drives on highway no problem.
Now I get a rather loud popping binding sound when I’m backing up and turning. And sometimes going slow and turning like going through the McDonalds drive thru, but not as bad and almost not noticeable and not all the time. It never happens when driving normal speeds.
I just figured out how to recreate the sound almost every time by cutting my wheel and backing out my uneven driveway.
It sounds like it’s coming from the rear but it is tuff to pin point.
Any ideas or tests to run?
CV Axle? Diff? Wheel barring? Some weird bushing?

 

[Mogman]

Every HMMWV I have owned does that so I don't worry about it too much.
19K on the DuraVee and there is no material on the magnetic plugs to show any problems
Some will say they should not do that and that may be true, but go to any Camaro forum and they complain about the "popping" from the factory GM Torson diffs.
There may be a "cure" so lets see what others have done!!

 

[Pstyckiewicz]

Thanks for the quick response!!! It was kinda driving me crazy because I couldn’t figure out what was make that loud crazy popping/boom sound but yet drive perfectly fine around town. Figured something was going to have a catastrophic failure and was going to have to learn to rebuild something else. Haha

 

[Coug]

Noises that only show up when turning and moving forward/backwards are commonly in the front CV joints.

 

[Pstyckiewicz]

Yeah it’s tuff to figure out where the noise is coming from exactly. Now I can recreate the noise I can see if I can try to pin point where it is. And if it’s normal.

 

[TNDRIVER]

So my truck developed a rather loud binding popping noise.
Back ground- drove the truck a few weeks ago on the highway and melted a fork in the transfer case. Drained oil- only had about a cup of oil in there, plus the pin was missing on the shifter fork. Fixed that cleaned it up put it back in there. Drives normal, shifts into each mode on transfer case fine. Drives on highway no problem.
Now I get a rather loud popping binding sound when I’m backing up and turning. And sometimes going slow and turning like going through the McDonalds drive thru, but not as bad and almost not noticeable and not all the time. It never happens when driving normal speeds.
I just figured out how to recreate the sound almost every time by cutting my wheel and backing out my uneven driveway.
It sounds like it’s coming from the rear but it is tuff to pin point.
Any ideas or tests to run?
CV Axle? Diff? Wheel barring? Some weird bushing?

And just to be safe, check the bolts on the brake disc rotors. Just to be safe.

 

[Mogman]

And just to be safe, check the bolts on the brake disc rotors. Just to be safe.

This should be done on ALL HMMWVs when received and and during routine maint.

 

[Pstyckiewicz]

Checked the rotor to CV’s those were good. What was loose was the bolts holding the entire brake caliper to the diff. I tightened those down after taking things apart to get at the bolts. It still produceses the sound.

 

[Mogman]

Noises that only show up when turning and moving forward/backwards are commonly in the front CV joints.

Changing to new half shafts made no difference in the popping, they were not changed for that reason but just the same.
In my case the popping is from the rear, which makes sense as the front diff. is not forced into as much "differential" action when making a turn as the rear.

 

[Pstyckiewicz]

Did another little test in the driveway. Reversed again cut the wheel hard to left and got the pooping noise. Pulled forward straightened out shut the truck off and put it in HL. Turned on reversed cut the wheel in the same manner. No popping.
Not sure what that means or confirms. Probably all natural sounds.

 

[Coug]

Did another little test in the driveway. Reversed again cut the wheel hard to left and got the pooping noise. Pulled forward straightened out shut the truck off and put it in HL. Turned on reversed cut the wheel in the same manner. No popping.
Not sure what that means or confirms. Probably all natural sounds.

If changing from H to HL eliminated the sound, then I'd say there is a decent chance it is inside the transfer case. HL locks the transfer case outputs so they spin together, instead of having the differential type action.

 

[Mogman]

If changing from H to HL eliminated the sound, then I'd say there is a decent chance it is inside the transfer case. HL locks the transfer case outputs so they spin together, instead of having the differential type action.

He also was winding up the drive train, (putting everything under a bind) it could be everything was running tight so no slack to "pop"

 

[Pstyckiewicz]

I hope it’s everything was tight and no pop. There is snow on the ground so I’m not going to be able to crawl under there until I get a warm day.

 

[Pstyckiewicz]

Update
So I could reproduce the sound by just backing up in a straight line in my driveway. After a few feet I would get a loud pop/bang. Took some time to stick my phone in there and take some videos. Narrowed the sound down to the right rear differential/brake caliper. I noticed in the video that the brake caliper seemed to be the source of the pop.
-what I did was I took the caliper off but kept it attached to the brake line. Just propped it up there out of the way. I then went back and fourth a few times and no pop. (So when I got the truck the brake line was disconnected and a bolt was missing from this caliper). Maybe there was an issue with the caliper before I got it.
-So after a few times of applying the brake with it off the cylinder thing was all the way out and leaking brake fluid. In addition the boot around it was destroyed.
-My thoughts are the thing sat in Yermo for years with the line not attached and maybe dirt and water got into the caliper. (Yes I cleaned it the best I could before attaching back to line when I got it). Now fast forward I think there is some sort of internal damage if the caliper.
-Ordered a new caliper and it should be at my house on the 6th.

 

[Pstyckiewicz]

One picture of the caliper in the truck and another after I took it out.

 

[Pstyckiewicz]

Also the sound it was making had a spring like noise.

 

[Pstyckiewicz]

Changed out the caliper and it no longe makes the noise! Crazy how that made that noise. Not sure what could have been wrong with the old one.

 

[TNDRIVER]

Changed out the caliper and it no longe makes the noise! Crazy how that made that noise. Not sure what could have been wrong with the old one.

THANKS for the follow up!

 

[Pstyckiewicz]

Takeaways from this:
Loud popping noise-check brakes.
To test:
-Remove brake caliper and pads.
-prop caliper up under there out of the way hooked up.
-Go back and forth a few time and see if it happens again.
-The brakes will be soft, the piston on the caliper will extend all the way out and leak so you will have a few times to test it out.
-If it is the caliper and you want to slap it back up there you will have to turn the piston for it to go back it.

Hope it helps someone out there haha

 

[Pstyckiewicz]

Oh as a disclaimer I would not drive anywhere other than your driveway or yard. The brakes will not work good at all.