"Clunk", my hub?

I'm driving a '97 Explorer. When driving up a slight rise at 40+, I'm hearing a "clunk" from underneath. Can occur several times climbing
the hill. Like one rotating piece of metal catching up with another. Brought it to a mechanic to diagnosis the problem and he said it was probably something wrong with "the hubs". GOOGLING for hubs, I see several articles describing how to disassemble, clean, lube and re-assemble, but before doing that, I was wonder if the symptoms I'm describing could indeed be wheel hub problems. Do these symptoms sound familiar? - Mike
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My experiences with bad hubs on the earlier Exporers ('91 and '92) was they would clunk while turning, not while going straight. No problems yet with the hubs on my '97. I have read of problems with the transfer case fully engaging the front wheels due to a dirty sensor in the case and/or uneven tire wear.
At least we can be pretty sure it's not bad radius arm bushings ;-)
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On Fri, 25 May 2007 16:01:52 -0700, "Ulysses"
. I have read of problems with the transfer case fully

I have an interesting coincidence to report. Just today I ordered an OBC II reader. How would a dirty sensor be represented? - Mike
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Michael Horowitz wrote:

97's do not have engagable hubs as far as I know, they have a vaccume engaged coupling one side of the front axle. Check u-joints first.     Jack
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wrote:

Jack - I see elsewhere Dr. Bob's explaination on how to replace U-joints. What is the test to determine if indeed it's the U-Joints that are causing my 'clunk'? - Mike
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Michael Horowitz wrote:

Easy way is to jack up one rear wheel and with the car in park try to turn it. If you feel /see a clunk when the driveshaft stops. Or just crawl under the car and try to turn the driveshaft, if it moves, replace the u-joints. Jack
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wrote:

Jack - Forgive me for not knowing the correct terms but that will improve shortly - I ordered the Service Manual and it will be in later this week. Tracking the torque backwards from the front wheels: two wheel axles meet at what could be described as a differential (but in the front), power is provided by a 3-4' drive shaft which connects this front 'differential' to the transmission. I assume a U-Joint where this drive shaft meet the transmission. When I hold the dome-shaped thing into which the U-joint is inserted and turn the drive shaft, I get play; not so at the front end, which is very obviously a U-joint. Am I correct in assuming there should be no play and that the joint that needs replacing?
If someone can tell me the correct termanology for what I intend to do, I'll GOOGLE for the repair procedure - Mike
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Michael Horowitz wrote:

You seem to get it, there are 2 u-joints, one on each end of the driveshaft, plus a cv(constant velocity)joint in the middle of it. To check them, put the explorer in 4 wheel low, turn off the engine and check for free play. The manual is a very good idea, got mine from e-bay for 9.00$ from ebay on cdrom. In 2 wheel high, the driveshaft should spin freely.
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wrote:

Wow. Mine cost $160. When you say driveshaft we're both talking about to forward one, not the one that powers the rear wheels - Just checking. Let me GOOGLE for "constant velocity joint"; I may have another question.- Mike
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wrote:

Hmmmm. We may have a disconnect. It appears the CV joints are on the forward axles. What I"m describing is the joint that fits into what I believe is the transfer case; a 'box' that is attached to the side of the xmission. - Mike
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Michael Horowitz wrote:

Yep, my front driveshaft has a small rubber bellows covered section in the middle, figured it was another cv joint. Has U-Joints at both ends.
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