Trans Whining Noise

[RyanbabZ71]

This is hard to describe. It also is only noticable when the radio is off (no background noise). After stopping and accelerating between 1K and 2K Rpms around 30 mph there is a whining type noise coming from my truck. It only happens if I am keeping it around this speed if I accelerate quicker like trying to get up to 45 then it doesnt do it but if I stay around 30-35 it makes the noise. It is kind of high pitched. I noticed this after having my trans filter/fluid changed not to long ago. I turned the radio down to listen for anything wierd and heard this. I do not know if it was making the noise prior (never paid attention). Its like the truck is hitting its resonance frequency or something and something under the truck may be making a funny noise. It may have nothing to do with the trans at all. Any of you have this experience. This is on a 00 Silverado 1500 Z71. Truck has about 51,000 miles.

 

Thanks

[DesertRace21]

I think you are complaining of the same noise I have on the same truck! Hopefully someone can help!

[mcreyaufmiller]

I'm lost here, sorry.

[budhayes3]

Can you tell if the noise is coming from front, rear, center? Maybe from the area of one of the wheels?

[min9861]

maybe engine noise? my truck does the same thing. but i have after market sound system with a stock deck. its usually caused by the hyalic converter or however you spell it. so ill need to get a new radio to make the whine go away.

[RyanbabZ71]

its coming from the front. Its not from the wheels but its like directly under or just in front of the floor boards (at least thats what it sounds like)

 

Its like its hits a certain frequency causing a high pitched noise. I checked the heat shields I seen and didnt notice any looseness. Truck drives and shifts fine (knock on wood )

[budhayes3]

Hmm, hope it's nothing with the trans (like the front pump), or the front diff. Nothing common like that, that I've heard of...I'll check out the TSB's on AllData tomorrow to see if there's anything there. Hey, you don't think it could be the air catching something and making a wierd wind noise under there or anything like that? Does it sound mechanical and/or rotational?

[RyanbabZ71]

its nmot a wind noise. Happens the same time right at 20mph and 30 mph around 1500 rpm??? Its like the truck is hitting a resonance frequency (vibration but i dot feel a vib)

and giving off a high pitched noise

[asilverblazer]

What about tire wear?

[RyanbabZ71]

I hope not I had my brand new less than 1500 mile BFG mud terrains on and I recently switcheed back to my ATs and the noise is still there. Its a metal sound under the truck definitely

[DesertRace21]

look for bearing play, my axle nut was backed off a hare.. solved my noise problem.. and i think made the truck safe to drive again!

[budhayes3]

Is there any way to duplicate the noise while not moving? Put it in park or neutral and rev the engine to the rpm that the noise occurs and hold it there? Maybe you can hear it under the hood, or have someone hold the throttle for you while you listen underneath. That could narrow it down if it makes the noise when there's no load on the vehicle and it's not in gear. Could it be frequency from the intake, or an adjuster pulley at the front of the engine, or maybe the power steering pump? Just tryin to throw some ideas at ya.

 

Does turning the steering left to right while driving change the frequency of the noise at all? If so, does it change more left or right? Sorry about all of the questions, just trying to be thorough to help you pinpoint the source.

[ness5575]

I had a similar noise, and it was very frustrating because it would only happen while it was moving, so there was no way to duplicate it while I was under the truck looking around. It happened at about the same speeds that you are describing.

I tried a bunch of stuff, finally I saw a heat shield under the center of the truck, between the doors (this was a while ago, so I forget its exact location) that was maybe 18-24" long and went in the direction of door to door. I bent the heat shield a little bit and have never heard the sound again.

If the rain and cold slow up here, i will crawl under the truck later and see exaclty what the shield is between.