Front end noise in 4WD (video)

I've heard this one on and off all winter. Sometimes the conditions are right and it's a little annoying. Other times it's not there. When it is, it almost sounds like a small diesel. It's just the rythmic sound, no groaning or whining or squealing or anything like that.

When it's doing it, it only happens in 4WD (silent in 2WD); only under light throttle; coasting or heavy throttle it goes away; only makes the noise between 30-40 mph.

Front diff fluid and transfer case levels are still up to the fill holes, both changed 13k miles ago. I can't feel any looseness in the u-joints and they're greased every oil change.

Just wanted to see if anyone else has heard this before. If it doesn't change or do anything weird I'll probably just keep it in the category of wacky tacoma sounds.

Lucky me, I finally got it on video tonight. Guess it had to be 13F to get loud enough.

http://youtu.be/GGd8hdz9tv8

 

Honestly it sounds more like tires to me, but hard to tell on video.

 

I have noticed the same thing in my truck. Maybe it always did it, but it only stood out to me recently.

I just turn the radio up. If something breaks, I'll have to deal with it. Like you, I have kept fluids changed regularly, u-joints greased and checked for play.

Where in MI are you?

 

That's probably why I didn't really notice it much before. If the radio is on, i can't really hear it unless I put the needle exactly at 36 mph where it's the loudest. When the speedo gets over 41 mph it's pretty much silent so it's only prominent when the roads are super icky.

Glad I'm not the only one. Misery loves company? Maybe it's just normal with that differential bolted to the subframe where sounds transmit well instead of isolated like the rear end. I hope so. I thought our diffs were supposed to get quieter in 4WD, not the other way around!

I'm in SW Michigan where the lake effect snow never seems to end. Well, except for today. The skies have cleared and temps are going into negative fahrenheit. The frigid temps probably helped my roommate's avalon snap its timing belt tonight. That's never a fun call to get at 2:30 in the morning. Still waiting for the cold to break something on the truck.

 

Maybe you put a weight oil in the diff that doesn't like the cold much? When it's engaged you'll be more susceptible to feeling road and tire vibes.

 

That very well could be. My old Dayton tires make all kinds of loud hums and vibes. I hope to have some new tires on within a couple weeks so that'll tell.

Diff oil is redline 75w90

 

I've heard some mixed things about redline in diffs before. At least in the 3000gt VR-4 realm... most people stopped using it because it wasn't smooth at all and causing problems. Most people switched to Royal Purple or lucas. May have no bearing on our trucks though, just something to note.

 

just noticed this same problem with my truck today.... only happens in 4wd under slight load, goes away when I take my foot off the gas.... hard to pinpoint where the sound is coming from.... sounds more like a ticking sound than a growling sound... Anyone else have this or figure it out?

 

What you are hearing is transfer case gear rattle, it's caused by increased noise of the transfer case gears meshing in fluid which is too thick from the cold.

My truck has the same noise in the winter. It can be very loud.

 

I'm starting to think transfer case too. If I lean forward enough it sounds like it comes from the shifter area. As long as it's not busted teeth in the diff I'm happy.

Caught it on video again yesterday

http://youtu.be/DZgpaW4J1Ro