Noise in 2WD with hubs locked...

[the_dingman]

Hey everyone,

I've been driving my 4Runner a lot lately, as my daily driver was on jacks in my garage. Now we've got lots of snow and I've been having fun.

Anyway, on my way in today I started having some noise from my front driver's side. It sounds kind of like a louder version of the rubbing/humming/slight whistle you get on some pavements. It began as only happening when driving over packed, bumpy snow patches in the road, then started happening later on dry pavement. It's only happening with the transfer case in 2WD and my manual hubs locked.

Facts:

-Hubs have been locked for a few days, working fine both in and out of 4WD
-Noise stops immediately when shifting into 4WD at speed
-Sometimes begins right after shifting back to 2WD
-No noise with hubs unlocked
-4WD seems to work find
-It's very cold (~2F with -15 windchill)

Any ideas? It's too cold for me to look at it right now, and everything is covered in salt. I'm trying to get an idea on what I might be looking at and if I should park it for a while.

Thanks in advance.

 

[fourwd1]

Could be a wheel bearing, or maybe CV joint.
Put ht e front end up in the air and check the drivers side for a bad wheel bearing. Try it with the hub locked and unlocked.

 

[the_dingman]

I was leaning on the CV axle as I would expect bearing issues to persist no matter the drive I'm in. I also had the bearings re-done about 2 years or ~10k miles ago.

It was a strange noise... Usually CV issues will cause clicks, but who knows.

My 35mi drive home with the hubs unlocked gave me no problems.

 

[Footofgod]

My vote is for CV. Mine did something similar last year. Changed the CV axle and problem solved.

 

[KidVermicious]

Check your fluid level, though... I've heard diffs with low or bad fluids make all sorts of interesting noises, and that'd explain why it only does it with the hubs locked too.

 

[the_dingman]

Jacked it up today, and there doesn't seem to be excessive play in the bearing. The wheel does more a very tiny bit up and down, but it's just enough to acknowledge that it moves. I'm not enough of an expert in bearings to say one way or another.

The CV boots look ok, but obviously I can't see what's underneath them.

As for the front diff, I want to change the fluid in it, but my quick look I couldn't find the fill plug. Can anyone give me a location on it? Do I have to remove the skid plate?

 

[KidVermicious]

Do I have to remove the skid plate?

Yup. 2 bolts on the frame rail, two bolts on the crossmember and it falls right out. Then you'll see your fill bolt facing forward about halfway up the diff cover, and your drain bolt underneath. Don't drain the fluid until you've got the fill bolt free, they like to seize up on you. PB Blaster and maybe some heat will be your friend.

 

[the_dingman]

I've had the cover off before, and I'm familiar with the stickyness, I did the rear diff a few weeks back.

I was hoping to avoid the cover as it's all of 15 degrees out today.