What is this noise/clunk in my drivetrain? Slip Yoke?

This noise started about a year ago, usually only noticeable on large dips at highway speed. Over time it has grown louder and more prominent with increasing occurrence. Now I get the noise over surface streets at 30-40MPH when there are big cracks or dips. It is easily reproducible on speed bumps, which I've provided some footage below. I can also feel the clunk below me/from the rear.

Initially, I feared the worst -- possibly pinion bearing. I was finally able to use my daughter's GoPro and a magnetic mount and it seems to be from the slip yoke. There is no movement in the rear where the driveshaft meets nor any movement in u-joints. I will be changing the u-joints anyway. Should I invest in that nickel plated slip yoke?

Hopefully packing some grease in there while the DS is out will help for now. What grease is recommended? I've seen some folks use some red from Lucas and others use the GM stuff.

Watch the video and let me know what you think.



Thanks.

Yeah definitely looks like its banging inside there, Never thought it could get that loud! I would inspect it and see what it looks like, sounds like metal on metal and dry to me. I would try greasing it and see if that helps, if its still there I would be looking into a junkyard, or new slip yoke. That thing sounds rough as it is.

Almost forgot awesome camerawork!

Good Lord that damn drive shaft has a lot of play in it! I honestly can't say for sure if it's the pinion bearings or not, because my pinion bearings went bad and it sounded nearly identical. But if I were you, I would go ahead and replace the U-joints, and grease the hell out of the slip yoke first. U-joints are CHEAP compared to a having pinion bearing replaced. I lube my slip yoke with the Lucas "Red and Tacky" grease. I literally gob a big pile of it all into the splines and work it all around with my finger. Basically have all the splines gobbed up with grease. If you do that, and replace all the U-joints, and it's STILL making that dreadful nouse, then it's highly likely that the pinion bearing is bad. Just hope that's not the case.

Will replace the u-joints (they've been sitting on my tool box for a couple months now) and grease the yoke. Hopefully that takes care of it, but it sure does seem like the play is excessive. Thanks for the replies.

Anyone else?

mattbta said:

Will replace the u-joints (they've been sitting on my tool box for a couple months now) and grease the yoke. Hopefully that takes care of it, but it sure does seem like the play is excessive. Thanks for the replies.

Anyone else?

Click to expand...

there is suppose to be play there, from when you go over bumps or objects/flex. Make sure you check if there is play in the differential yoke in and out, that would be more of a concern aside from the banging in the front.

After a 1700 mile road trip my Hoe developed a similar clunk in the rear end that only seems to happen occasionally from a slow take off/ start. I would prefer to just add some grease first before throwing money at a new slip yolk but I have seen multiple people state that greasing the slip yolk will contaminate the ATF and might mess up the tranny...anyone know if that IS the case?

Clunk is gone! No more noises on speed bumps, no clank accelerating from sudden stops. Truck just feels so much more solid and not like it is going to fall apart.

I did not pack the yoke with grease like I intended, but threw parts at it. New u-joints, pinion/carrier/axle bearings, races, seals and spider gears. If I didn't get such a good deal on the labor from a trustworthy shop, I probably would have started with u-joints and grease the yoke. And you can hear in the video some howling from the pinion -- there was some definite pitting on the bearing and spider gears.

mattbta said:

Clunk is gone! No more noises on speed bumps, no clank accelerating from sudden stops. Truck just feels so much more solid and not like it is going to fall apart.

I did not pack the yoke with grease like I intended, but threw parts at it. New u-joints, pinion/carrier/axle bearings, races, seals and spider gears. If I didn't get such a good deal on the labor from a trustworthy shop, I probably would have started with u-joints and grease the yoke. And you can hear in the video some howling from the pinion -- there was some definite pitting on the bearing and spider gears.

Click to expand...

parts cannon ftw.

Yeah. Eventually the bearings were going to give so figured why not. Overall, it cost me a fourth of what other independent shops and dealers quoted.

Great Video !! Now I know what mine is doing every time I come to a stop sign. '00 Tahoe 292,000 mi. Original U-Joints, Yoke, Bearings. Mine will need everything you just had done.