1995 K1500
 

hey guys my pickup is acting up , for the past couple months when gas is applied, and only when gas is applied i have a loud humming noise that smoothes out the faster i go, but doesnt start until i hit 25 mph no matter what gear im in , as soon as i let of the gas it goes away, front cv shafts are good, u joints are good, rear pinion bearing has no play in it. Im stumped, help would be appreciatted

Driveshaft CV ball?

ball? what do you mean ?

Speculations... (since it isn't engine speed or specific-gear dependent)

In addition to Red's suggestion...
Tire wear
Driveshaft out-of-balance
How's the rear diff gear oil?
Have you tried the 4-wheel drive engage/disengage?

Any more info on the problem -- does it do it in neutral, things like that?

RH77

tires are nearly new 33 inch BFG all terrains, with no unusual tire wear , all the weights that were on the shaft are still on , rear diff oil is ful both front and rear, it not in the 4 wheel drive already tested that, somewhere in the tranny on back

How many miles on your truck. Your fuel pump might be going bad.

its not the fuel pump, been checked, its in the driveline , 216,000 on the truck 55,000 on the tranny, tranny flushed 4000 ago, goes in for pitman arm , idler arm , and alignment tommorow

exhaust leak?

lol no , its in the driveline i can feel the humm in my pedal

Put an extra pair of socks on.

Not to familiar on how Chevys are setup but I'm assuming one of your driveshafts, probably the front one, has a Double Cardon Joint. Two u-joints and a CV ball in between them. When the ball goes bad and starts to seize up you either get a vibe, harmonic, or what us jeepers call "Angry Sparrows" cause it sounds like a bird from hell has decided to nest underneath.

Pull the front shaft and see if it goes away, else its something else. Easiest way is to just unbolt it at the diff and type it up somewhere. Make sure you stay in 2WD.

You might have a bad shock. The shocks on the Heep are adjustable, when I set them too soft I get a minor vibe in the back at speed. But once stiffened up, the vibe goes away.

yeah ill need them when im walking back to town cuz I didnt fix the vibe.


thanks red

You'll find the problem and have it fixed in no time, look at the people you have working on it.

Yeah i know this forum has the best of the best

did you lift the truck? Lifting would change the pinion angle and sometimes that cause funny vibrations/noises from the drive shaft.

What about a bad inner axle bearing in the rear diff? My guess is that something in the rear end is going down. Bearing, gear, etc.

is it a new brand or tread pattern on the tire

OMG! I have a 1995 Chevy Cheyenne 4X4 and found the carrier bearing bad. It is in the driveline.

You have a Metro too! LOL

yeah haha thats pretty rare, well i took the truck in and they said it was a common problem with chevy in the driveshaft, said there was nothing they could do about it unless i wanted to buy a new one, and it wouldnt hurt it to drive it that way, wish i had a 98 metro instead of a 93 though haha

Wish I had a pre-1995 instead of a 1998, but yeah :rolleyes: