I thought bearings had gone bad in the OD section - which is what happened 50K miles ago. So I took it back to the transmission shop to have them check it out. After driving it with them remote sensors hooked up so they can listen to everything they concluded it was probably the OD. They replaced all the bearings in the OD and it's still making the noise.

The noise, singing/howl, sounds like it's coming thru the floor of the cab. On the freeway on the level it's fairly quiet, start pulling even a small grade it gets progressively louder till it maxes out then tapers off when it levels out again. I've had the rear diff carrier out to rebuild the Powr-Lok and at that time there was no junk from disintegrating bearings, the ring and pinion teeth looked good and no slop in the pinion. The noise was happening before I rebuilt the Powr-Lok.

Got any ideas?

 

Driveshaft joints?

Is it just howling or vibrating too?

Sounds like the tranny shop missed something inside the trans to me....

 

No vibration other than the usual 16 year old buckboard old truck type stuff! In other words, doesn't feel like a u-joint and I've never had a u-joint howl. I'm suspecting something in the trans itself, not the OD.

 

carrier bearing maybe

 

could it possibly be a wheel bearing? my car did the same exact noise until i replaced the wheel bearings.

 

when its hard to get the direction, put it on jack stands spin the driveline under brake load, use a mechanics stethiscope, or long ratchet extension, held to your ear, to listen for sub audibles, that compare to the noise at load, remember your brakes will also transmit noise, poking at each driveline component, you should be able to isolate the culprit, watch those spinning tires!

 

I guess if a professional can't find it I'll have to! Just did 4.5 hours of driving today, 2 round trips to Yuba City, return trip pulling a heavy flatbed trailer with a 2wd crew on it up some 40mph grades and she ain't dead yet!

 

and drive shafts......