This is probably the last nail in the coffin

[410Fortune]

On VW's the axles are bolted to the transmission cups with 6 Triple square bolts that like to strip out

I have the Audi CV axle tool in my tool box...those VW half shafts sure are fun (NOT) There is a reason I work on these Fords...they have earned our respect!

Easy test: Remove front D shaft, is the noise still there?

 

[sehaare]

I have the Audi CV axle tool in my tool box...those VW half shafts sure are fun (NOT) There is a reason I work on these Fords...they have earned our respect!

Easy test: Remove front D shaft, is the noise still there?

for the VW - you have to have the right triple square socket and make sure that the bolt head is completely cleaned out and the triple square fully seated or you will strip out the bolt head. Initially I had cheap tools before I finally had to money to get better stuff.

for the front drive shaft - I saw another thread here, where they got into an argument that driving the XLT with the front drive shaft removed would damage the 4WD. So I'm hesitant to do that. Also even with the driveshaft removed doesn't the half shaft still turn some of the gears in the differential? and since I found the differential had about half the gear oil in it that it should then I don't even trust that any of the gearing is not worn out.

I've been looking over my maintenance records (and I've started to remember more details on the suv). I had heard this noise 20K miles ago and replace both front axles/half shafts thinking that might be the issue (simple, cheap attempt to fix the problem) and that had no effect on the noise. The front drive shaft was replaced by ford 10K ago (i was out of town at the time -OUCH). and I know that some time since 2004 I replaced one wheel hub, I just can't find it in my records.

So most of the front drive train is new which narrows down the issue. And when I found that the differential was only about half full, after the shop said that the noise was coming from there. I'm pretty confident that it is the differential.

And just as a PS going back over my records, I've replace both upper and lower control arms on both sides. Inner and outer tie rods on both sides, sway bar links on both side and sway bar bushings, new ball joint both sides. new shocks, all in the last 3 years and new rotors and pads 4 years ago. So seeing all the work that I've already done, throwing another $200 for a low mileage used front differential and about a days worth of labor due to the rust up here is just a no brainer. (plus It will be one new thing that I haven't done on a car before -what's the use of having tools if you are not goign to use them).

Thanks for the help

Steve

 

[410Fortune]

Removing the front shaft and driving will hurt nothing. Its just a test.
Yes our trucks have a "live front axle" which means the tires both spin the half shafts (cv) and both shafts spin inside the diff which turns the ring and pinion. There are no hubs and no CAD (center axle disconnect) so the ring and pinion is spinning when the truck is moving.
I would remove the front d shaft and go for a drive

After that is the noise is still present the next thing to do is drop the front diff and open it up

DANGER Some of us will actually put the truck up on jack stands, all 4 tires off the ground. With the vehicle pointed AWAY from the house/shop and on 4 stands SECURELY you can then let it idle in 4wd and the source of noise is usually very obvious....Do not get underneath the truck when doing this you are just an observer and somebody should be in the drivers seat the whole time DANGER. It usually takes just 10 sec or so of running to confirm where the noise is occurring and this is ONLY after you have exhausted all other options. This is also assuming a front end shake down has already been performed. Shake down includes getting both tires off the ground and using your muscles to look for any looseness, check the tires at 12 and 6 and 3 and 9 o clock for play in wheel bearings, ball joints, tie rods, and control arms. Spin the tires look for noises from brakes, bearings, axles. Check pinion for any play up and down in and out....that sort of thing. Not many "noises" can get past a front end shake down test......looseness can be pretty easy to spot and sometimes it takes a small pry bar to find it.

 

[sehaare]

Thanks for the additional suggestions, Unfortunately, I now have to leave town for a work emergency so this is going to have to go on hold until I get back. The noise that I hear isn't bad enough that I'm worrying about immediate failure but I want to get to it as soon as I can to prevent any possible further damage to other components.

Thanks again, you can have all the tools and manuals, but nothing matches the experience learned from having done this many times before.