04 Sierra Front End Humming

RJMMass · March 16, 2010

Good evening,

I have a 04 sierra with 120k on her and ive been dealing with a humming for about 9 months now from the front end somewhere but only between 30-35mph. I just cant pinpoint it ive had my mechanic check it and he cant seem to find it either. Ive replaced the tires since and it wasnt that. Ive done a fair amount of searching on the net and here on the forums but cant seem to find anything.

Thanks for any help...

Bob

gbayfisher · March 17, 2010

Good evening,
I have a 04 sierra with 120k on her and ive been dealing with a humming for about 9 months now from the front end somewhere but only between 30-35mph. I just cant pinpoint it ive had my mechanic check it and he cant seem to find it either. Ive replaced the tires since and it wasnt that. Ive done a fair amount of searching on the net and here on the forums but cant seem to find anything.

Thanks for any help...

Bob

Have you checked the front bearings? Is the truck in 4 auto?

i would bank on the bearings though, they have been known to go early.

knipper_03 · March 17, 2010

I would bank on the bearings.....I had to replace one in my truck last weekend.

Make sure your auto 4wd isn't staying engaged. If you have a drive shaft that spins freely then its not your u joints. If it doesn't spin freely in park and in 2wd then it might be your u joints.

Find a new mechanic. If he can't trouble shoot the front end of a pickup I would not trust him with a fisher-price crescent wrench.

RJMMass · March 17, 2010

Thanks for the quick responses...

He has already checked the bearings and said everything looked fine...but i guess we will have to take a closer look...ive checked the 4wd and it does switch back and forth from 2 to 4

Won-hunglo..it happens all the time if the radio is on or not

CapitalTruck · March 17, 2010

Is it engine RPM speed related or vehicle speed related? (if you were to operate the truck at any engine RPM at 30-35 mph would it still do it?)

gbayfisher · March 17, 2010

I would get him to check the bearings again just in case. As mentioned, check to see that the 4 auto isn't stuck on, perhaps the switch is malfunctioning. Check your CV joints though they would cause more of a clicking sound but you never know!

Have you checked all U-joints? Hanger bearing can hum as well so check there.