Constant buzzing noise?

[DK5]

It's a '90 350tbi, but no, only happens with the engine running

 

[KohlTrain]

My 87 with the 700 and around 130k made that sound when pulling hills or trailer. HOT tranny TC.

 

[4X4HIGH]

Sounds to me like radio static interference. Remove the fuse for the radio and then start the engine and see if the noise is gone.

If this turns out to be the issue (pretty sure it is) there are several things that could cause it. If you don't use resistor plugs, or wires this is the biggest reason for it, the other would be installing an aftermarket radio and choosing a "dirty" 12 volt power source. There are radio noise suppressors for this reason.

 

[DK5]

I don't think its the radio (not that kind of buzzing sound) plus, it is the factory radio. I'll try anyway for the heck of it though.

I'm leaning towards the tranny because it sounds like it is coming from there. Its more of a rattling mechanical noise than a buzzing radio noise... if that makes sense

 

[Never Satisfied]

I know mine is definitely not the radio.

 

[4X4HIGH]

I don't think its the radio (not that kind of buzzing sound) plus, it is the factory radio. I'll try anyway for the heck of it though.

I'm leaning towards the tranny because it sounds like it is coming from there. Its more of a rattling mechanical noise than a buzzing radio noise... if that makes sense

If it turns out to not be the radio then you could unbolt the torque convertor from the flexplate and push it rearward then start the engine and see if the noise is still there (this would eliminate the trans as the problem entirely).