View Full Version : Well I got the "hum"...

10-31-2005, 02:54 PM
Well on the way to/back from Talladega this weekend I noticed that my car would HUMmmm, HUMmmm from underneath/rear end at exactly 89 mph and get louder and more steady the faster I went.

(No, it's not my rotors you gobblers!;) )

Someone mentioned a while back that my 4:10's might require an Al driveshaft if/when it developed a vibration.

I think I have the vibration, but it was fine for over a year... I wonder what made it want to start acting b!tchy now?

Anyway, does this sound like the dreaded gear swap/vibration problem that requires the new driveshaft or what?

Any of you guys that have done rear gear swaps experience this?

11-01-2005, 06:49 AM
Just a thought, sounds like a precursor to premature wearout. My explorer did that for the longest time but it also made a horrible squeel when reversing. Eventually it just self destructed after about 100k miles. If the noise is still there (after you change tires once they wear out) it may be the gear alignment (backlash, or mesh). It may just be harmonic resonance of the road surface or tire tread pattern. If the same noise can be heard on different road surface or still occurs with different tires, it may be the rear gears. Drive shafts may do just that when the yokes begin to wear out but it will be heard most of the time at any speed. It may be related to the thermal expansion of the gears in the rear which relates to improper mesh or backlash. :side:

11-01-2005, 07:15 AM
I would go with the tires. Had similar problems with other vechicles. Sometimes just rotating can help. Like Aussie said start there if the noise still persists move to the gears.