was saying that if you drop the front shaft and lock your center diff (cdl) you can see if it makes a difference. might help chase it down......might not (again, hard to make out the noise), but 8 nylocks is a cheap test.

 

You getting any vibrations?


sounds like a bad center ball bearing, or a dry one at least.

 

No, no vibrations but I quit when I got to 50 mph when the noise came on......both drive shafts were replaced by P.O. with updated one's......guess I'll go burn it down the HW and see what shakes. "center BB in the front driveshaft" ??? or BB in the t-case outputs ?

 

Pull the shaft, feel for a bad bearing, you'll be able to tell. Then go for a little drive with the tcase locked to make sure of any assumptions.

 

PULLING both shafts today and will post......

 

Keep in mind that the E-Brake is connected to the Rear Driveshaft. Be sure to block the tires if you are not jacking it up onto blocks. I ALMOST learned that the hard way on a hill. Lift ONE back tire and the truck will roll.

EDIT: I see you are in a '99. I'm not positive if it's the same as my '03. Maybe someone else can confirm.

 

All the same. Just pull the front, the rear is a pain, you need one on to drive around also.

 

Does it whine in neutral? higher pitched when revving? If so its the transmission pump. Probably put the trans in sans the alignment dowels. If it is not rev related and is road speed related, Its most likely something in the transfer box.

 

Had time today to pull off the rear Drive-shaft and inspect and it was fine. Pulled off the front as well and inspected all U-joints etc. ....all is well.
Will re-install the rear in the Morn and manually put it in CDL mode and see what happens.
The odd thing is if I stop then go the sound is not there for a few hundred yards and then just starts almost like it was "sprung" if that makes sense. Any chance it's tied to the ABS or traction control system? Like I said the 3 amigos are on full time now since the tranny and t-case rebuild but prior the Amigos used to come and go. The brake reservoir had drained out while it sat all winter and I had to bleed the valve on the passenger assembly to get the caliper to work. Does the ABS have a pump? Maybe I need to bleed the ABS or am I reaching for straws? IDK it's maddening considering all the friggen time I have put in. Here is another vid I shot from inside the cabin, If you turn up your volume you can hear it perfectly..........will post more results tom !
It whines in N if I get it up to speed Then shift it from D. Can not reproduce the sound in R. Driving in low-range produces exact same sound. The sound is only present while going over 15 mph. Not engine related as it sounds great when NOT Driving.

** here is Vid , click on Rover2
Rover2 on Vimeo

 

My driveshaft is bad, its brand new, literally ~300 miles on it, but its making a whining noise and vibrating. Put just the rear on and lock the CDL and check it out then. DONT put the front back in yet.