Bad torque converter?

[Rusty knuckles]

I have a 71 charger with a 318/auto trans. At moderate speed (40-45mph) under very light load, like just maintaining speed on flat road, it will make a buzzing noise like something spinning against a piece of tin. I'm fairly sure its coming from the transmission and at one time thought it may be the little tin dust cover on the front bottom of the transmission. But after taking that off and tweaking it several times I don't know that it is the issue anymore. I'm wondering if the torque converter may be giving up? No other symptoms than what I've described and to my knowledge the drivetrain has roughly 120k without rebuild.

 

[66Satellite47]

Doubt that a torque converter makes buzzing noise. Check to see that the converter to flex plate bolts are tight. How about any other heat shield like parts, muffler or ?? A buzzing sound can come from bad U joints too. Check them carefully.

 

[Cranky]

No noises when cold and or backing up? Had a buzzing sound with my 95 Dakota once and the trans filter was pretty clogged up but made the noise when in reverse. Does the buzzing sound change if you give it some gas or let off? Did you drive it with the dust cover off and it didn't make the buzzing sound?

 

[Rusty knuckles]

No noises when cold and or backing up? Had a buzzing sound with my 95 Dakota once and the trans filter was pretty clogged up but made the noise when in reverse. Does the buzzing sound change if you give it some gas or let off? Did you drive it with the dust cover off and it didn't make the buzzing sound?

Yes it does change. If I step on it a little to load it or completely get off the gas and coast it stops. And like I say only at this particular speed in high gear. If I throw to 2nd at the same speed it doesn't do it. It also doesn't seem to do it in any other gear but 3rd.

 

[Cranky]

I'm betting the torque converter bolts are rubbing the shield. Had a car that did that once. The converter does move back and forth a bit when on and off the gas and the fluid pressures change....

 

[Kern Dog]

You have a resonant vibration that is related to the exhaust system.

 

[Rusty knuckles]

I'm betting the torque converter bolts are rubbing the shield. Had a car that did that once. The converter does move back and forth a bit when on and off the gas and the fluid pressures change....

I will check it out. Thank you