Intermediate thumping from under '05 Tahoe

[CincyTahoe]

2005 Z71 w/125k. I was driving home last night and got an occasional rapid thumping from under the truck - honestly it sounded like machine gun. Jumped in this AM and had it happen again. I cannot reproduce the issue on demand. Seems to happen randomly while driving 45 - 50mph on smooth pavement. Any ideas?


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[Tonyrodz]

Did you look underneath? Maybe around the driveshaft area, or where ever it sounds like it's coming from. It's amazing the stuff that gets caught in moving parts.

 

[CincyTahoe]

Did you look underneath? Maybe around the driveshaft area, or where ever it sounds like it's coming from. It's amazing the stuff that gets caught in moving parts.

Yes. Nothing obviously loose or tangled in the drivetrain. The noise is intermediate and I cannot seem to reproduce it.


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[retiredsparky]

Could be a dry u-joint on one of the drivelines, or cv joints on front axles (they turn all the time even in 2WD) intermittently locking up. Drive train problems can be difficult to figure out.

Or it could be tranny or transfer case related. The rapid staccato noise means it is something rotating as opposed to suspension.

 

[CincyTahoe]

Could be a dry u-joint on one of the drivelines, or cv joints on front axles (they turn all the time even in 2WD) intermittently locking up. Drive train problems can be difficult to figure out.

Or it could be tranny or transfer case related. The rapid staccato noise means it is something rotating as opposed to suspension.

Definitely seems driveline related. What's odd is how intermittent it is. Seems to happen when warm and at speeds 45-50MPH. The last time it occurred (3 days ago) there was a cadence to the sound - 3 pops then a pause - repeat. I tried speeding up, slowing down, switching from 2 wheel drive to 4, step on brake, turn off the heater, etc. nothing I did make it better or worse. My 1st thought was the plastic inner fender had come loose as was making contact with the tire on the driver's side.


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[cmc76]

total longshot, but try compressing the shocks one corner at a time.
i had a rear blow out, that made a very odd " thump". i couldn't get the sound to duplicate after exhausting myself. then i climbed on the bumper to reach the roof rack, and it happened.

 

[Tom Joad]

Go under it with a clean rag. Check the tansfer case especially the area of the "long neck" where you insert the rear driveshaft.
Clean all space between the parts that make this long part stronger. Check for drawing on the net. Check if there's holes where the oil pump dig through the rear body.

Also check the level of liquid inside. that may be a clue.

 

[CincyTahoe]

I had an opportunity to get under it this morning. I checked the transfer case for any pin holes - none, pulled the fill plug - fluid looks good, checked the u-joints - seem ok. Took it out for about 30 miles - not a sound. Mystery continues...


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[ALVTAHOE]

Check your e brake shoes. Mine was making a sounds like that as well and it ended up being the e-brake shoe falling apart.

 

[08HoeCD]

Beyond all the good advice offered, check all your bushings to make sure all are intact and in place.
A disintegrated bushing will separate and cause a knocking/banging noise between sway-bar and bracket until replaced.