Posted by bryan on June 05, 01 at 10:30:32:
In Reply to: Deja Vu??? posted by BIG BLUE on June 05, 01 at 08:29:58:
I have the exact problem you listed below. My noise comes on at 35 and tapers off at 55-60. Let off the gas and the noise is gone. I used to get the noise all the time until I added some GM limited slip diff lube and some Lucas gear oil addative and now I only get it at the above speeds. If the rear end isn't going to detonate I will live with it.
Bryan
: Wow, I thought I was going crazy! I have this EXACT same sound you are describing, but I don't consider it a "whine" as much as I do a hummmmm type of sound. Here's what I have; 97 Sub K1500/3:73/5.7L. I notice if I'm coasting at between 45-50 it does not do it, but if I "touch" the gas pedal I can hear the sound you are describing. It almost sounds like the hum of an aggressive tread tire, but only between 40-50 mph does it do this and only if I touch the gas a bit.
: Same as you, my U-joints seem fine, tranny checks out ok, tires are balanced etc. There is a web page for diagnosing rear diffy sounds, but the closest I can come to compare is a ring and pinion noise. I'm stumped too. If anyone else has any ideas let us know.
: Thanks,
: BIG BLUE
: : Thanks for the feedback. No bug shield or other appendages. 2wd 1500 not 4x4. Not tires. Never been hit. Sounds very much like mid to rear underbody area. only when you have the gas on between 40-50mph. let off and it goes away. Checked oil in rear and it looks and smells fine. universals feel fine and really don't have much time on them. I was thinking it was a typical suburban sound. otherwise this thing is showroom cond. and never even used hard.