Hummin Noise

Hey guys. I got a humming noise in my 2WD Taco.
It's been going on for awhile, just now it's pretty loud. I got my Alignment n Balanced my AT2s and the noise is still going.
I noticed it only makes the noise when my foot is on the throttle, and goes away when I let off. Then when I threw it in neutral it also went away. Any idea what it could be? Tranny? U- Joints? Diff?
Thanks- David

 

Greasing the U-joints would be a good start but I'll guess they are toast.

 

Can you humm a few bars for us?

 

Hmmmmmmmm And as I go faster the pitch goes higher and when I slow to a stop I hear it go down

 

I know it's hard to pinpoint, but can you tell where the noise is coming from? Rear diff or middle near tranny.

 

More near the middle. That's why I fear it's tranny

 

Any other symptoms from the tranny?

 

No tranny problems or symptoms of tranny issues

 

No tranny problems or symptoms of tranny issues

 

Like Steves said, try lubing the u joint. See if there is extra play in it. How many miles does the truck have?

 

I don't think you can grease the u-joints on a 2wd. No fittings. Try driving it a short distance then feel the u-joints. If one is failing it will get really hot.
I just changed one for a friend and it got hot enough to melt the plastic on the bearing cap seals...

 

Well that sucks.

 

Some do some don't is what I've gathered from my readings here. My Prerunner ( 2WD ) has jerk fittings on the U-Joints. Better to look and see.

Opps. Meant Zerk Fittings.

 

Lol. Sorry, it fits well and made me laugh.