AWD Differential Replacement

[rizzjc]

Mighty nice of you, but still a LOT of work when he could replace the driveshaft to test that out first. Especially if he's paying someone to replace the transfer case.

 

[valley_man0505]

I seem to be having a very similar problem with my 98 Mountaineer. It started as a slight vibration but within a couple minutes, it turned into a large clunking noise and then a metal on metal scraping noise. Took it to a friend of mine who is a local mechanic and he said it was the U-joint. He replaced the U-joint and it worked fine for about 3 days, then the same noise all over again. I am still waiting on the second diagnosis, which will be from a different mechaninc since I got stranded in a different town with it this time. The question is whether the U-joint going bad could be a symptom of something else. If I replace it again, is there something else going on that could cause it to go bad again?

By the way, mine is also AWD and the sound is coming from directly under the drivers' seat.

 

[rizzjc]

Which "U-joint" was replaced? The front driveshaft has a CV joint at the rear, where it attaches to the transfer case. That is usually what goes bad, and is not, from my understanding, replaceable. You have to replace the whole shaft. The transfer case is a "popping" or banging under load. In my limited experience, if the noise is constant, then it is the CV joint in the driveshaft. You would need a new driveshaft.

 

[valley_man0505]

Just got a quick response from the 2nd mechanic. Apparently, this time the problem is with the rear drive shaft whereas the first problem was with the front.

 

[Vermonter]

I have a 99 AWD Mountaineer that has been making a constant noise with speed sensitive vibration for sometime now and the shop said it was the X-fer case. The shop says they pulled the front shaft, road tested...still vibrates. Pulled rear shaft and road tested...still vibrates, so x-fer case must be the issue. I can pick up a case for $250...should I pull the trigger and go for it?

 

[Tanfoo]

Hey, sorry for being unresponsive for a while. Checking the drive shaft was one of the first things I did.

I replaced the transfer case and reinstalled the front drive shaft and everything is running great!

Thanks for all the info!

EDIT: I just read my old original post... man I sounded like an idiot ! I've learned a lot in the last couple weeks...

 

[valley_man0505]

Well, I had to revive this thread since the noise in my AWD is back almost one year after it was fixed. You can see from my previous posts, which were from last February, that I am having an issue very similar to that of the OP. Last year, I had someone replace a U-joint and the problem went away for a couple weeks. Then, the noise came back and a second mechanic replaced the rear driveshaft. He said the issue was in the CV joint in the rear drive shaft. After that, the problem was gone...up until now. The noise is now back and I am really struggling to figure out how this could back after almost a full year. I am going to take it in to another mechanic very soon. Does anyone have any recommendations?

 

[ericautopart]

You replaced the u joint in the front you said but did you ever check the CV? I thought explorer rear drive shafts were single u joint on both ends but I could be wrong?

 

[410Fortune]

okay let me put my 02 cents in here

Son in law has a 97 Explorer XLT 4.0L/auto/4x4 180K miles
Making clunking noise when turning, binding up at times when truck is warm

So over x mas break:
I checked out his CV shafts, original CV's at 180K miles, they were loose loose.
I had some CV's laying around with half the miles, so we installed those, same issue

I got under the truck, no looseness in the front end, driveshaft, t case, anywhere
IN fact it looks great for 180K miles


So I did the brown wire mod, took 12 minutes to do with the help of the Exploreforum
Noise and binding are GONE with the switch off = front d shaft disconnected = noise gone.


My guess is his driveshaft is on its way out, though no visable slop or tears, play, etc
Next we are going to drain and fill the 4405 t case, my guess is the 180K mile fluid is BLACK
Plan for this truck is a 1354 manual conversion, he is saving $$$ for this now, so we are trying to avoid having to buy a $160 driveshaft in the next two-three weeks

Brown wire mod = worth a shot! Of course if it snows his truck will be right back to binding and popping because he will need his front d shaft, but at least we bought some time to locate a 1354 manual and linkage! also a 97 2wd GEM

I suspect driveshaft still......that was nice of you JT to send a t case! geesh!! I shoulda called you LOL

my advice: try the brown wire mod, search this forum for "BWM"

 

[valley_man0505]

Okay, so here are some updates. I had a chance to crawl under my truck to take a closer look at things. It was actually the front drive shaft that was replaced last year, not the rear. So, last year when the noise first happened, the front U-joint was replaced. This made the problem go away for about 2-3 weeks. When the noise came back, a second mechanic replaced the front drive shaft since he said the problem was with the CV joint. Now, the problem is back again almost a year later. I couldn't get a good look at things myself when I crawled under since I don't have access to any type of lift, so I took it in to another local mechanic today. Once again, the problem is the CV joint. He had me look at it while the truck was on the lift and there was an obvious tear in the rubber boot in the CV joint and there was some play in the shaft where it entered the CV joint when wiggled by hand. Could there be some underlying issue causing this CV joint to keep failing? Or is this just a big coincidence caused by a faulty part? I can't believe this thing failed again when the part was brand new less than a year ago. I have only owned this vehicle since Nov. 07 and this will be the second drive shaft replacement.

Also, I have seen people write about removing the front drive shaft and drive-testing to see if the noise goes away--is this something that could be done long-term? If so, perhaps I would be better off just taking the driveshaft off altogether and just dealing with a rear-wheel drive vehicle in the snow.

 

[MountaineerGreen]

My.02- in some cases, the transfer case is the culprit- BT93 bought a 97 with a clunking on acceleration, driveshaft boot was torn, replaced it, still a clunk on hard acceleration. We pulled the case and split the case halves to discover the chain was stretched to the point of "jumping" inside the case. Ordered a new chain from the ford dealer, put it in and problem was solved. The case never poped with the front shaft out, there was no load on the chain to make it slip. If you have a new driveshaft and still a pop, look to the case. You can replace the chain if you can pull the case- it's not that hard and way better than a risk of a JY case.

 

[valley_man0505]

I'm not so sure it is the transfer case, though. Last year when this happened, the noise went away completely once the driveshaft was replaced. Do you mean there is a possibility that something wrong with the transfer case could be CAUSING the driveshaft failures though? Like I said, the noise went away last time it was replaced. I won't get to fix it this time for about a week or two when I have the money, so I guess I will see if the noise goes away again this time.

By the way, I don't know if this is related or not, but the mechanic also pointed out that both drive shaft seals were leaking. I don't really even know what those are. All I know is that the labor estimate to replace them was 3 hours!

 

[valley_man0505]

Finally found the problem

Well, I had yet another front drive shaft go out on me. Now that winter is over, I took it into a mechanic and told him to just disconnect the front drive shaft since I didn't need AWD anyway. Well, he did this and then the truck wouldn't move. It turns out the transfer case had gone out a long time ago and none of the power was being sent to the rear axle. EVERYTHING was going to the front, which was overstressing the front drive shaft, which is why the CV joint kept blowing out on me. I'm glad someone finally figured it out, but it is kind of bittersweet--I have was planning to trade it in even before this latest problem anyway.

 

[gijoecam]

Well, I had yet another front drive shaft go out on me. Now that winter is over, I took it into a mechanic and told him to just disconnect the front drive shaft since I didn't need AWD anyway. Well, he did this and then the truck wouldn't move. It turns out the transfer case had gone out a long time ago and none of the power was being sent to the rear axle. EVERYTHING was going to the front, which was overstressing the front drive shaft, which is why the CV joint kept blowing out on me. I'm glad someone finally figured it out, but it is kind of bittersweet--I have was planning to trade it in even before this latest problem anyway.

What you're saying is not possible with the all wheel drive transfer case. What you have, however, experienced is a failed viscous coupling insode the transfer case. The gearing inside the transfer case acts like a center differential, and the VC acts as a 'limited slip' unit between the front and rear outputs. Without a functional VC, removing one of the driveshafts will result in teh other one spinning free.

The VC is the bulk of the cost of a new case. Bummer.