Broken AWD. Bad Viscous coupler? Bad Driveshaft?

[Slicer89]

Little background, It's a 2000, XLT Explorer, V8, AWD 163k. Not sure of what Tcase or transmission. Anyways.

I'm not sure what the issue is. Here is a video of what it does.

http://www.youtube.com/watch?v=-Do440UFanQ

It doesn't do it nearly as bad on dry surfaces. But it still does it.

It DOES NOT do it while turning. (Like, turning into a parking spot)

It only does it while accelerating either in forward or reverse.

I got up under it and couldn't feel any play in either Drive shaft (could be because it was under a load, too.) There doesn't appear to be any fluid leaks / cracks in the Transfer case.


I realize I had another thread, but not with enough information.

Can anyone help me?

 

[RomeovilleIL]

It sounds like a bad CV joint in the front shaft. Pull the front shaft and take a test drive. It has 4 cap screws that hold the front u-joint straps on and 6 bolt on the CV with 3 moon clips. The CV is usually fairly well stuck with a thin layer of rust to the case, but a couple hits straight upwards on the CV with a heavy hammer (piece of scrap 2X4 is helpful in getting a straight hit) after bolts are out will knock it free. The front shaft is not driveline balanced to the best of my knowledge, so marking orientation is good practice but not critical.

 

[Slicer89]

It sounds like a bad CV joint in the front shaft. Pull the front shaft and take a test drive. It has 4 cap screws that hold the front u-joint straps on and 6 bolt on the CV with 3 moon clips. The CV is usually fairly well stuck with a thin layer of rust to the case, but a couple hits straight upwards on the CV with a heavy hammer (piece of scrap 2X4 is helpful in getting a straight hit) after bolts are out will knock it free. The front shaft is not driveline balanced to the best of my knowledge, so marking orientation is good practice but not critical.

I really, Really really hope that is the only issue. I do not feel like buying a transfer case or front axle. It still gets power to the front wheels because I had to drive in 16'' of snow the other day and could see my front tires spinning along with the back.

What do you mean driveline balanced?

 

[my98nnj]

If you brake torque it, does it make the noise?

 

[RomeovilleIL]

The transfer case in the AWD is actually a viscous coupler. It is mechanical, full time power to both front and rear driven by a chain with some limited slip properties so the AWD never turns off. Removing the front driveshaft and test driving will quickly show if that is the problem.

By driveline balanced I mean the shaft is balanced after installation. Usually only done on modified drivetrains where there may be pieces out of alignment.

 

[RomeovilleIL]

Have you tried standing outside the truck while someone else drives it to isolate the noise to the center, front or rear of the truck? Would give you a quick assurance of not being the axle.

 

[bill06447]

Sounds like what my truck was doing. Bad CV joint. I bought the Dorman CV repair kit and a cross joint for the other end, both will be going in the front driveshaft tomorrow as long as the temps are above 40

Bill

 

[SoNic67]

I think too that's the front axle CV joint. Once you have it down, replace the front U-Joint too. Don't drive without the front shaft, will damage the Viscous Coupler inside Transfer Case (that's actually a true Central Differential with limited slip).
My experience with this:

http://www.explorerforum.com/forums/showpost.php?p=3252817&postcount=31

 

[bill06447]

Replaced both the CV joint and the U-joint in the front shaft today. Pretty simple straightforward fix, once I realized the bolts holding the cross joint to the front diff were internal T30 Torx and not 3/8

Bill

 

[Slicer89]

If you brake torque it, does it make the noise?

You mean holding the brake and giving it gas? Or slamming on the brakes?

I will look into a CV joint once the weather is a little better.

 

[Slicer89]

Still haven't had much luck. The noise is still there and getting worse, if I accelerate hard it will do it even when doing 70mph.

Today, I tried holding the brake hard down and flooring it... Truck wouldn't move, didn't slip or anything

Only time it would make the noise is when I left off the brake and accelerated in either forward or reverse... But holding the brake hard down and flooring it, the rig didn't move or make the noise.

 

[SoNic67]

Still haven't had much luck. holding the brake hard down and flooring it, the rig didn't move or make the noise.

Of course it will do nothing! The CV coupling at the end of the front shaft needs to rotate in order to make noise! It won't rotate without the wheels rotating.

What kind of "luck" are you expecting? To fix itself?

 

[Slicer89]

Of course it will do nothing! The CV coupling in the shaft needs to move in order to make noise!

What kind of "luck" are you expecting? To fix itself?

Yeah, I totally expect it to fix itself. I also expect the bills to pay themselves as well.

When I had my Chevy truck, That made basically the SAME noise.. if I had it in 4WD and held the brake down and gave it gas, it would make the noise because the chain was skipping teeth.

I realize 4wd =/= AWD. But if the chain was skipping teeth, it would do it when the brake is applied.

I'm trying to isolate what the noise is exactly. I'm not gonna pay a shop $120+ an hour just for them to tell me it was something like a BAD CV joint... Or something as horrible as a possibly grenaded transfer case.

I'm having people tell me one thing that it's the CV joint going bad, and then I'm having other people tell me nope, your transfer case is broke. The chain is slipping teeth.

 

[Turdle]

OK. Again. Once you get the front drive shaft out, it will be apparent if the cv joint is bad if you inspect it. Look closely at the little rubber boot ( yes, you do have to remove the shaft) and look for a tear. If it is torn I absolutely 100%guarantee the cv joint is toast.

You can drive it like that for a little while , order the new cv, rebuild it and re install ==joy.

While you are under there, look at the rear drive shaft. There is a slip yoke, which you should grease. It will also make a thunk when it is dry.

Now, go pull that front drive shaft out and take a looky.

 

[SoNic67]

You can take the shaft out yourself.
You need a Torx 30 socket (4 bolts at front U-Joint) and a 10mm one (6 screws at CV end).

 

[jremington59]

You can take the shaft out yourself.
You need a Torx 30 socket (4 bolts at front U-Joint) and a 10mm one (6 screws at CV end).

Lets not forget the jack and the blocks for the wheels.

Just jack that baby up, get under there on your back and have some fun. Don't forget the glasses to keep the rust chunks out of your eyes. I found it easier to take out the two torx bolts on the bottom and then to move the truck a little to get the other two rotated to the bottom because mine were rusted in and didn't want to come without a little heat. I'm sure this makes it sound more appealing, lol.

 

[SoNic67]

Lets not forget the jack and the blocks for the wheels.

I managed to squeeze under without a jack or ramps.
But definitely always use blocks for wheels and goggles for rust debris.

 

[SmoothJimmy]

If you remove the front drive shaft, you are essentially disabling the park feature of your transmission. In other words, the rig will roll forward or backward if left on a hill. Many guys have mentioned that they removed the shaft, went inside for a few, the returned to see their Ex rolling down the street. Make sure to block the wheels.

If you remove the shaft and the noise goes away, it doesn't definitely point to either the shaft or the transfer case as you are essentially taking both out of play. Others have mentioned some tests for the shaft and some versions are rebuildable. You might also drain the transfer case and look for any metal shavings that might be apparent if the chain is so loose it is skipping gears. If your case is like my 4404, you can stock your finger in drain hole of the tcase and scrape the bottom for settled metal bits but you would most prob see some suspended in the ATF too. My tcase made horrible sounds at low speed before I replaced the ATF in the tcase for the first time. I think the normal duty service is 9k miles.

If you do find issues with the tcase, consider looking at a junk yard for a similar model. When cash for clunkers was in full swing a few years back, my local yard had about 20 4404's and 4405's sitting around. You can rebuild many components and then swap it in for the current one and not lose too much down time. New 4404's cost something like $1200 and the junker versions $100-$200.

 

[rabbit91]

If it's the case, do a manual tcase swap. BW4406, best mod I have done to my truck

 

[bill06447]

One of these threads that makes me want to scream! Put it in neutral and give the front shaft a shake! If that's such a huge deal it takes 19 posts to clarify, time to drop it off at a shop

Bill