Clunk when accelerate - driveshaft?

[dukenilnil]

Update: Clunk when accelerate - Not the driveshaft

I'm not very mechanically inclined but this forum has been very helpful.

I have a clunk when I accelerate my 1997 5.0L Mountaineer that has gotten progressively worse.

Based on the post below, I think it's the front drive shaft (hope it's not t-case).

What I want to know is: (1) I removed the front drive shaft and drove it around the block and the sound went away completely. Is it almost certainly the front drive shaft or could it still be the T-case and the T-case only makes the noise when the front drive shaft puts resistance on it?

(2) In removing the front drive shaft, I noticed that the roller pins on the caps of the u-joint at the yoke where falling off. Now, neither cap has any pins. Could it simply be the missing pins and should I just get new caps for the u-joint on the front of the shaft?
Thanks

discussion referenced above: http://www.explorerforum.com/forums/showthread.php?t=227481&page=2

 

[nssj2]

That u joint is a great place to start. If that doesn't resolve it though, the CV joint on that drive shaft is notorious to failing. Options to solve this are get a new driveshaft, or take your old driveshaft in to a driveline shop. Then you can get a custom conversion flange that goes from the cv output on the transfer case, that will accept a traditional u joint on your new custom driveshaft. In my area, both the brand new, and custom setup run the same price.

 

[dukenilnil]

Not the driveshaft...what now?

So I replaced the front drive shaft with a new shaft. I test drove it 10 feet and still had clunk on acceleration and now on stopping. There is occasionally a clunk when making a hard turn but it does not happen every time unlike the other clunks.

I had previously taken off the front drive shaft and the clunk went away. I have again removed the front drive shaft and that eliminates both the acceleration clunk and the stopping clunk.

The odd thing is, the old drive shaft has a completely disintegrated CV boot, so I was sure it was going to be the drive shaft (I will try to post pictures).

If it's not the drive shaft, is it definitely the transfer case? Could the old drive shaft with the damaged CV boot be so broken it ruined the transfer case or something else?

I had been driving with the clunk sound (getting progressively worse) for a couple of months including some 8+ hour road trips.

Getting desperate and afraid it is going to be an expensive repair I can't afford or that is beyond my limited abilities.

 

[dukenilnil]

Link to photo

Photo of old drive shaft and damage below. This is damaged, right?
But it apparantly was not the cause of the clunk because it still clunked with a new drive shaft.

Is the driveshaft definitely broken and need replacement if it doesn't have the rubber boot?

http://mountaineer1997.shutterfly.com/

 

[dukenilnil]

Any help?

 

[gavin]

Photo of old drive shaft and damage below. This is damaged, right?
But it apparantly was not the cause of the clunk because it still clunked with a new drive shaft.

Is the driveshaft definitely broken and need replacement if it doesn't have the rubber boot?

http://mountaineer1997.shutterfly.com/

if the rubber boot is missing, yes it needs replaced.

if the clunk is still there with a brand new shaft, it's very possible the chain has stretched causing excessive play to the front output, which would most likely only be noticeable with the front shaft installed