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Clunk in drivetrain

klosch80

New Member
Joined
March 29, 2012
Messages
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City, State
Baker, NV
Year, Model & Trim Level
1999 Explorer 4.0L 4X4
Hey all,

New to the forum here and got some issues.

My 1999 explorer 4.0L 4x4 auto has 172,000k on it. Just drove from Portland to Baker, Nevada and noticed a clunking, almost jerking thing. Its hard to describe but it doesn't feel like the motor is stalling, more like tranny or rear end? It only happens at higher speeds and above 2k RPM. It is not while shifting. It definitely seems worse while pulling hills or any time I put more load on the motor.

I have a check engine light but the code is P0174 which I hear is common on these motors and related to MAS or vacuum leaks and don't believe they are related, but maybe I'm wrong about that.

Any help is appreciated. Thanks

Kevin
 



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three common sources of a driveline "clunk" (there may be more, but these are relatively common)

1. BW4405 transfer case output shaft bore becomes elongated
2. Rear driveshaft splined slip-joint is either worn or needs lubricant
3. Worn u-joints

I would try lubricating your slip joint first since that's essentially free. I believe the "right" stuff is a special blue-green Ford grease, but I think a good Moly grease would work fine.

You can check for #1 by grabbing the rear driveshaft, right where it comes out of the transfer case, and feeling for any up-down play.
 






Thanks, I will look at those this evening
 






three common sources of a driveline "clunk" (there may be more, but these are relatively common)

1. BW4405 transfer case output shaft bore becomes elongated
2. Rear driveshaft splined slip-joint is either worn or needs lubricant
3. Worn u-joints

I would try lubricating your slip joint first since that's essentially free. I believe the "right" stuff is a special blue-green Ford grease, but I think a good Moly grease would work fine.

You can check for #1 by grabbing the rear driveshaft, right where it comes out of the transfer case, and feeling for any up-down play.

1., above: I think the output shaft bore is actually the I.D. of the output shaft bearing. In any event, if the bearing is shot, or its locating pocket in the case is wallowed out (unlikely), if sufficient clearance exists to "feel" up-down movement, the seal should already be leaking, or will be, soon.

2. Think wobble at this location will cause vibration, as the driveshaft spins out of "true".

3. A possibility. But since driveshaft revolves VERY fast, "clunk" describes a low-repeat-speed noise, like from something turning much slower, or not turning at all

Easily checked, visual or by wrench: Broken or loose rear transmission mount. Broken or loosened rear axle center-section mounting.

Just a few additional thoughts. imp
 






Ok so last night I crawled underneath to check things out. No play in the rear drive shaft at the transfer case. U joints all look good. I noticed when trying to check for play in the rear driveshaft that I could move the transfer case and transmission, so now I'm thinking about the transmission mount idea.

This truck was laid on its side in the snow this winter. My girlfriend on icy roads :/ I replaced passenger window, checked all fluids, took her for a test drive and everything seemed ok, but now a broken mount could definitely be a possibilty. Not sure I know what is meant by the center mount on the rear axle, but I will look around in that area to see what I can find.

Thanks for the suggestions.
 






Ok so last night I crawled underneath to check things out. No play in the rear drive shaft at the transfer case. U joints all look good. I noticed when trying to check for play in the rear driveshaft that I could move the transfer case and transmission, so now I'm thinking about the transmission mount idea.

This truck was laid on its side in the snow this winter. My girlfriend on icy roads :/ I replaced passenger window, checked all fluids, took her for a test drive and everything seemed ok, but now a broken mount could definitely be a possibilty. Not sure I know what is meant by the center mount on the rear axle, but I will look around in that area to see what I can find.

Thanks for the suggestions.

My error on the center mount: 2nd. gens have solid rear axle, not center frame-mounted differential, my apologies. Broken transmission mount almost always involves failure of the rubber-to-metal bond of the parts, and may not be "seeable" until the engine/transmission assembly is raised slightly to allow removal and inspection of the mount itself. imp
 






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