Is this "noise finding" test OK to do?

[rcolosi]

I've been dealing with a drive train whine at 40-45 MPH. ..definitely not the tires.

I jacked the back end of the truck up and had it securely on jack stands in a place where there was plenty of room, to get the drive line up to speed to hear the noise. Other than the obvious..the truck falling off the stands... is this going to cause problems? I did notice the ABS light went on right away...I'm guessing since the front wheels were stationary while the rear were turning. I just want to make sure this wont dork up the ABS system, or harm the transfer case, etc. It turns out I did not hear the whine, so now I want to jack all 4 wheels up and try it in 4WD. Again, I want to make sure this is ok to do, assuming the truck is securely jacked up and stable. Also, this is on a 2004 Ranger super cab 4WD.

Thanks!

 

[Earl43P]

Yeah, I've done that.

If your jackstands are secure, do it.

Could you be hearing the front hub grease excluder seal? Pretty common for those to make a speed-dependant whine of sorts, pretty high - pitched. Almost sounds like a whistle when it first starts. Gets drowned out by ~45-50 mph.

 

[rcolosi]

Hi Earl,
That's actually good info. If I do not find it, I am going to bring it to the dealer, and I'll definitely mention that.