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Mike S.
Mike S., Chevy Mechanic
Category: Chevy
Satisfied Customers: 6818
Experience:  ASE Certified Master Technician
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2002 chevy suburban: I think I might have a u-joint going out.

Customer Question

I have a 2002 chevy suburban. I think I might have a u-joint going out. I'm hoping it's not more than that. Here's the problem.
When I shift from drive to reverse or reverse to drive, I hear a clanking noise. Not all the time but sometimes. If I'm stopped and accelerate fast, I hear a very loud, hollow, tinny noise. It sounds like it's right behind the front seat but it's hard to tell. This happens if I accelerate fast in forward or in reverse. If I accelerate slowly I don't hear this noise. If I have the truck in neutral and hit the gas, the engine revs but I don't hear this noise. As I gradually go faster, the truck starts to vibrate at about 20 miles per hour, is really bad about 40 miles per hour and then not quite as bad once I reach 55 miles per hour. It kind of feels like your driving on a gravel road.
Submitted: 5 years ago.
Category: Chevy
Expert:  Mike S. replied 5 years ago.

Yeah, that's usually a good sign that 1 or both of the u-joints are worn. If you come to find out that one is bad, you might as well do them both. Remember to mark it first, cause it is balanced. Just take a piece of chalk and draw a line across the driveshaft right to the differential housing.

You can tell which one if you get down under there and take the driveshaft in one hand right near the u-joint and grab the transmission yoke on the front or the flange for the rear on back and push and pull with both hands and twist back and forth also. Any movement and they will clang or you can just stick a big screwdriver into the u-joint and move the screwdriver around in case you don't want to get your hands all dirty.

When checking the back, also check the ring and pinion backlash by grabbing the flange and turning that clockwise and counter-clockwise. There should be a little play and maybe a clink but no clunk. Also, move the flange up and down to make sure the nut is tight.

If the seal leaks do that while you have the driveshaft out, same as in the front if the tranny seal is leaking.

When under there also look for any weights that may have flown off the driveshaft although it may be out of balance just because of the u-joints being worn.

Do you know how to replace u-joints? You need a big vise and a big hammer.

Mike S. and 7 other Chevy Specialists are ready to help you
Customer: replied 5 years ago.
I have not replaced u-joints before. Is it complicated or is it fairly simple as long as you have a big hammer?
Expert:  Mike S. replied 5 years ago.

Simple. Once you get the driveshaft out, remove all the clips from the bearing caps if there are any. Sometimes they have some plastic stuff in them, you can tell by a little hole and maybe a blue tip thing and no clips. If you heat them up with a torch they kinda expand and come out like a worm coming out of an apple.

Once you get the clips off or those plastic things. If any clips are stuck, just use a socket and hammer and tap on the bearing cap a little and try to squeeze the clip together again and remove it.

Once you get the caps ready to come out, open your vise about 4-5 inches, enough to set the front yoke on top of both jaws and the driveshaft hand free, so you are catching the u-joint on the ends, then bang on the driveshaft right where the weld is and bang one cap out, turn it over and bang the other cap out, then turn the vise in some and lay the u-joint on top of both jaws and bang them caps out. Make sure you place the grease fitting hole so the compresses instead of separates when the driveshaft is spinning.

Set the u-joint in and gently place both caps on by hand as far as they will go but don't hammer them yet or you will loose the needle bearings and they will fall over. Now, set the u-joint exactly in the middle so it goes in a little bit on each end cap, then place in vise the entire thing between both end caps and squeeze it all together slowly. Then when caps are flush, if you have to put the clip back in use a socket and hit the socket with a hammer untill you can get the clip in.

 

remove u joint bearing caps

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install bearing caps

 

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