Spun out, now AWD / 4WD grinds/ratchets

[Qyota]

On the way to Gramma's house (no joke), on an icy dirt road. Going about 20 mph in 2WD, and the rear end got loose. We spun around, and the rear driver side hit the ditch first. Luckily, it was a pretty flat ditch. The engine stalled, however.

Back on the road, it's driving fine. I decide to put it in AWD (push button on stick), and within a few seconds after engagement, there was a fairly nasty grinding sound from the mid-front area underneath. Took it out of drive, then pulled the stick back into 4WD. It went in, but the grinding and ratcheting continued. Not constant, but on/off.

Drives fine in 2WD. Got to Gramma's, played around with it a bit in the driveway, and the problem is still there. I haven't had any issues whatsoever with AWD or 4WD in the 5 years I've owned it, and I use it at least once a month, if not more in the winter.

Thoughts? Front diff? Transfer case? CV axle?

Video of noise: http://youtu.be/szN8B1cJjyw

Thanks!

 

[shootmymime]

What year? Does the 4wd constantly flash when it engages or stays lit?

 

[Qyota]

99, multi-mode, lights behave normally. They stay lit when engaged.

 

[Qyota]

Boxing Day bump. Can anyone suggest a starting place?

 

[wake_rider]

Mid-front? Remember that your transfer case is fairly far back, so if the sound is pretty forward, I would think to start first at the front diff and cv's.

Have you been underneath with a pry bar to see if there is a bolt or mount loose causing some "chattering?" Is it making the noise whenever you're going straight, in a turn, both, on more slick surfaces where the diff might be slipping, etc...?

As a disclaimer, I am throwing questions out there just for brainstorming general diagnostics. I am by no means educated in drivetrain diagnostics, but am just trying to generate some ideas for places to start. Hopefully it can help a little.

 

[Qyota]

Thanks wake_rider. Sound may be coming from transfer case (directly below shifters), or from front diff. I couldn't quite tell, and I didn't leave it engaged long enough to really investigate. The sound was bad enough that I took it out of 4WD very quickly.

We were going straight on an icy dirt (no dirt exposed) road, at less than 20mph. No turning involved. However, in the driveway (my testing after the first experience), I was basically just rocking it back and forth slowly (forward, then reverse, putting it in and out of AWD and 4WD), and it was OK until I tried to move forward with a little gas...then the winding/ratcheting sound came up, including some jerking/clunking from what I assume was the driveline. Wheels were turned to the left (about 1/2 way) during these tests.

I'm about to roll around on the garage floor looking for answers. Will lube the driveshafts and look for anything obvious. There are no leaks that I'm aware of. Garage floor is clean, undercarriage is dry.

 

[shootmymime]

Check u joints and cv axles for starters. That kinda the weakest parts on our vehicles

 

[MVP]

Check u joints and cv axles for starters. That kinda the weakest parts on our vehicles

x2

I too suspect CV joints. I have something similar going on after taking a few dips too hard. :doh:

I wouldn't have thought the dips would cause these issues, but it sounds like the clicking noises that I used to hear up in Alaska when the front wheel drive cars would lose their CV joints.

Google "cv joint failure sound" and see if that helps...

 

[Qyota]

Thanks for the ideas, but this doesn't sound like CV clicking...this is a teeth-not meshing gear-y sound. The reason I suspect transfer case is because of the speed of the sound. It's something that's spinning at a relatively high speed, compared to wheel speed. Again, the noise was there going > 1mph in the driveway.

Just greased and inspected all U-joints, and they seem fine...nothing loose or broken.

Half-shafts are "new" remans from NAPA about 2 years ago. I don't do much for off-roading, certainly nothing that would stress CVs.

I guess I'll have to try it again, and get the phone ready to take some video. I just hate to think what is grinding, and what I'm breaking by testing it!

 

[LittleCaesar]

You could drain the fluid and see if there are metal shavings in it.

When is the last time you used 4wd? How old is the fluid?

 

[Qyota]

Front diff hasn't had a "real" gear oil change since I don't know when (can't remove the drain plug, did a suction-empty & refill about 25K miles ago). Rear diff and transfer have new gear oil in the past 2 years (also ~25K miles). I use the AWD quite often in the winter, rarely do I use 4-hi or 4-lo...maybe once or twice a year. I've used both AWD and 4-hi several times already this winter with no issues. Is this just a coincidence that this happened right after our spin off the road surface? The truck was in forward gear, but spun backwards off the road, and the engine stalled. This was in 2WD, so I can't imagine what that could have done to the 4WD system.

YouTube video with the sound:

http://youtu.be/szN8B1cJjyw

<iframe width="420" height="315" src="//www.youtube.com/embed/szN8B1cJjyw" frameborder="0" allowfullscreen></iframe>

 

[SilverRidgeRunner1]

Try this out put the vehicle into Awd and then shift it to 4W hi does the sound go away, then if yes shift out of 4wd hi. does the sound come back

 

[Qyota]

The video shows the sound happening in 4-lo, and yes the condition exists also in 4-hi. But it does seem to be more prevalent in AWD.

Front diff, or transfer? It can be hard to tell from the video. I'll try again to remove the drain plug from the front diff tomorrow, and change fluids in both if I can.

 

[LittleCaesar]

It sounds (pun) as if the sound is emitting from the transfer case, but only when the brakes are applied?

When my transfer case went out on my Bronco, it sounded like rocks inside a dryer. The bearings were shot, but the noise was constant when engaged, like a wheel bearing on its last leg. A used transfer case found in a junkyard and I was good to go.

It seems as if the shaft is not engaging, causing the transfer case to bind so to speak.

The best remedy may be to get it on a lift.

 

[Doc2012]

You're not engaging all the way into 4WD. You can see the front shaft start to go in, but then it stops.

It could be your actuator going bad in the Multi-mode.

Can you shift it into 4WD without that sound?

Like move the lever to 4H and 4L and have it not grind?

Actually, I'm willing to bet that's what it is.

Take it off, clean it, and see if that helps.

You can take your center console out, take the shift boot off, and engage the 4WD with a long screwdriver. If you need more info on this, I'll be glad to make you a video tomorrow.

That would tell you if your shifter bushings are bad it not.

Basically, the issue you're having is that your 4WD isn't engaging properly.

 

[Qyota]

Thanks for the ideas. The video shows the problem in 4-lo. The problem is also there in 4-hi, and AWD. I'd love a video of what you are describing. If there is something I can clean and re-try, I'm all for it!

I agree that this seems to be the issue...partial engagement, or drive splines not fully engaged. Going to replace fluids today in the transfer and rear, and hopefully the front diff if I can get it drained.

 

[Doc2012]

[MENTION=38561]Qyota[/MENTION]

I no longer have ADD in my Runner.

There's an actuator in the back of your t-case. Take that off, and you're more than likely going to find your problem.

If you need the FSM for it, i can send Ya the pages.

 

[Qyota]

Small update:

Changed rear diff lube. Old stuff was in OK shape, still purple, and no obvious wear. Magnet on the drain plug had a nice little mound of fine shavings on it...normal stuff.

Transfer lube drained, and it looked straight up silver. Very fine particles, nothing big, but very consistently silver. I'm fairly confident the problem lies in the T-case now.

Still could not get the front diff drain plug out, so I sucked out as much lube as I could, and re-filled. The old stuff looked dirty, but not terrible. Not silver. The diff lube seemed a little low, so now it's topped up.

I haven't driven it yet, going to do more research on the actuator.

 

[Qyota]

Small update: new fluids have done nothing to fix the issue. Next step will be testing all the switches on the front diff and transfer. Joy!

 

[Qyota]

Plan is to swap in a used (but lower mileage) t-case from a 4runner from the SW region. Hoping to find one that isn't too rusty. Mine has 194K miles on it, so basically anything will be better, assuming it's not been beat up.

I have no other ideas. If it was the front diff, I wouldn't expect grinding from the transfer case. I think what's happening is the t-case actuator isn't fully engaging the front driven gear.

The really strange thing is that the 4WD indicator lights operate perfectly. You'd think the lights would flash if the actuator wasn't fully engaged. Grrrrr...