Vibration coming from transmission maybe torque converter

[Wyatt Tankersley]

Its a 2003 chevy 1500 ls z71 So I've been noticing a vibration, it feels like its coming from around where the trans meets the engine maybe the torque converter. The vibrations happen at around 2000-4000 rmps. It doesn't happen every time I'm accelerating. It doesn't really make the truck lag to much but I'm just curious what could be causing it.

[asilverblazer]

When you notice the vibration, put the truck in neutral let the revs go down or/rev the engine up - does the vibration change? Isolates the vibration to either engine or drivetrain. Engine loaded vibrations could be misfires. (Check engine light on?)

 

Try different combinations of gear selection, speed, rpm - a speed only related vibration is not caused by engine or transmission. Speed related vibrations check tire balance, drive shaft balanced and true, worn u-joints.

 

When you notice the vibration lightly rest your foot on the brake (only enough to turn the brake lights on) does the vibration go away? If so check the torque converter clutch.

 

Could also be something as simple as some mud build up on the tire or rim. 

[Wyatt Tankersley]

So it is definitely not tires being out of balance or u joints being worn. I don't take thus truck in the mud so definitely not mud or anything like that. I can definitely feel it right next to my foot when on the gas pedal. I will try messing with putting it in different gears and all that. Check engine light is on but it's for one of those stupid evap codes

[Wyatt Tankersley]

19 hours ago, asilverblazer said:

When you notice the vibration, put the truck in neutral let the revs go down or/rev the engine up - does the vibration change? Isolates the vibration to either engine or drivetrain. Engine loaded vibrations could be misfires. (Check engine light on?)

 

Try different combinations of gear selection, speed, rpm - a speed only related vibration is not caused by engine or transmission. Speed related vibrations check tire balance, drive shaft balanced and true, worn u-joints.

 

When you notice the vibration lightly rest your foot on the brake (only enough to turn the brake lights on) does the vibration go away? If so check the torque converter clutch.

 

Could also be something as simple as some mud build up on the tire or rim. 

UPDATE 

So I guess I would describe it as a brrrrrrr noise it happens in 2 gear at about 4k rpm and in 3rd gear at about 3k rpm I can also put it in neutral and drive it to 3k rpm and it will do it and same thing in park. I check the fluid and it's maybe an 1/8" of and inch to a 1/4" above the full line. The color of the fluid is still kinda purple but alittle brown. The noise is definitely coming from where the engine and trans meet.

[asilverblazer]

Can you have someone hold the RPMs where it is making the noise in Park and listen with a mechanics stethoscope? Is it the sound causing something to vibrate - the catalytic converter is in that area - the media inside could be broken and rattling. Heatshield... Happening in park and neutral leads me away from transmission. 

[Wyatt Tankersley]

On 11/3/2022 at 9:21 AM, asilverblazer said:

Can you have someone hold the RPMs where it is making the noise in Park and listen with a mechanics stethoscope? Is it the sound causing something to vibrate - the catalytic converter is in that area - the media inside could be broken and rattling. Heatshield... Happening in park and neutral leads me away from transmission. 

So I change the trans fluid and filter this week and I didn't seem to help to much maybe alittle better but hard to tell. Drain and change again maybe? Also it's been happening for a while now but when I first start the truck in the morning it has a very small knock or tick only fir a few seconds till the engine warms up alittle I always thought it was the engine but you think it could be the flex plate?