Drivetrain squeak?

Can anyone give me some troubleshooting tips on this or know what the problem might be? I've got an 05 v6 AT 4x4, yesterday I started hearing a squeak coming from directly under me outside the truck. It only happens 0-30ish mph and sounds like birds chirping. Matches engine rpm not wheel rpm. It does not squeak when rolling in neutral or reverse, only forward gear. But in 4x4 it's quieter and goes away sooner. In the rain it went away completely all day. I can't tell if it's coming from inside the transmission or maybe the output shaft, or carrier bearing? The rain thing has me leaning toward carrier bearing. I need to be under it while its in gear rolling to hear it better and that's hard to do by ones self. So far, I'm not having any vibrations, other noises, shifting issues, or evidence of fluid leaks. Any ideas? Thanks in advance.
-Mr. O'Foolery

 

Welcome to TacomaWorld
Do you lube the drive shaft zerks?

 

Crawl under it and inspect your u-joints

 

Center bearing as well.

 

I'll be tinkering with it today, so I'll look into these things. I did look at the ujoints while I was under it, but not very closely. I was more focused on the bearings thinking that was the source.
Thanks sirs and/or madams

 

I would try greasing all the ujoints first and see what happens. I have this issue currently but only in reverse and it's definitely my ujoint nearest the transmission

 

U Joints.
The best way to inspect them is to remove the drive shaft from the truck and inspect ( manipulate ) each joint by hand. Replace them all if any are stiff or loose.

 

Update. Greased all the u joints, no difference, actually getting a little louder. But the noise isn't coming from a joint It sounds like it's coming from the middle of the shaft between the carrier and diff. When I was down there greasing I could hear it better than the other day. And now it squeaks when rolling in neutral, it didn't do that before. Should I be shopping for driveshafts?

 

You should also check all the heat shields along the exhaust system.

Diagnose and isolate first, then buy the needed parts and undertake the repair.

 

I've been chasing this noise for a few days. I've checked everything and it's coming from the driveshaft between the carrier and the rear U joint. It's the only thing that makes noise when the truck is off and I roll it back and forth while underneath. I've tracked the source of the noise down. I've never had a driveshaft break, so I don't know the symptoms. I'm asking if this noise is one of them.

 

Did you remove the drive shaft and inspect the universal joints and carrier bearing?

If not, then it could still be one of those, regardless of where you think it is coming from. The only thing else would be the slip joint and you would still need to remove the drive shaft to grease it.

 

The next step is to pull the driveshaft check the joints by hand