speed dependent knock?? Not U-joints...

[JStieger]

Lately, I have been trying to chase a speed dependent low pitched knocking sound.



I replaced the u-joints on my front drive shaft about 2 months ago due to similar symptons (except a tick-tick sound) as well as obviously blown seals. So today I decided to catch up on some preventative maintenance and replaced my rear drive shaft joints with aftermarket greasable joints as they were starting to look pretty worn too. This job went well and was pretty straightforward. As part of the job I felt for play in the transfer case slip splines, carrier bearing, drive shaft slip splines, and rear pinion. All felt normal with no clunking or out of plane movement. I then went for a test drive and the low speed, speed dependent knock is still there!



I push in the clutch and it seems that the knocking seems to go away slightly. Hard to say over the engine and road noise though. The sound volume is road speed dependent and the sound only happens on low speed deceleration.



Any ideas? Frankly, I don't know how long it's been there as lately I have been driving with the radio off to hear the singing turbo...



BTW I am glad my new Bilsteins are coming in Monday from Geno's. I noticed today that all my shocks had fluid leaking from them

 

[Bertram65]

I had a speed dependent knock on my truck turned out to be driver's side front axle u-joint, truck had 35k on it, luckely caught it under warrantee.

 

[JStieger]

Thanks for the reply...



That's interesting... those are the only u-joints I haven't changed on my truck yet. When your axle u-joints went bad did they make the knocking noise in straight ahead driving or only during turns? I haven't tried pinpointing this condition yet - but I'm heading out to SLC for a day trip today so I'll experiment with different driving scenarios. With these trucks and especially the long bed it is so hard to pin-point the noise location due to sound carrying!



I have the new axle shaft u-joints already as well as big hub puller, but don't want to tackle the job unless I'm absolutely got it narowed down to these joints due to having to probably spring some $$ for new wheel unit hubs too (I have no warranty due to my choice of modifying my truck).

 

[Bertram65]

It was hard to hear it on my truck, if it was on the passenger's side I may have not heard it until it got worse. I would shut the engine off and coast to try and pin point it, be carefull as it is very hard to stear with no power stearing, and I would have to put it in nuetral to restart it as the auto won't start in gear. My noise seemed to come and go, it was more noticable when in a straight line, cornering made it quieter.

 

[Diesel Power]

loose bolts

check the upper and lower controll arms, mine did the same thing and it ended up being loose bolts---mine did it in reverse and when takeing off especially in 4 wheel drive :-laf hope this help you

 

[Diesel Power]

loose bolts

mine problem was on the driver side towards the cab

 

[JStieger]

Thanks for the advice!



I'm going to jack up the front end tomorrow morning, pull the tires, and check what I can - put a wrench on what I can too to see if anything is loose. It doesn't pull to one side or anything as well as no weird tire wear. If it was the diffs I would figure there would be oil puking from some seal.



I did crawl under today and looked over all the driveshafts and they checked good since they have new u-joints anyway. I also cranked the wheels to each side to inspect the axleshaft joints and they looked "OK". Otherwise, I do not know how to check them unless jack up and turn the wheel as well as a prybar to see if anything is loose (???).



The knock is on coast or deceleration only - doesn't matter if in neutral or in whatever gear, but seems like it matches the tire revolutions (like a stone in the tire tread). If I get on the throttle then no noise.



I'll also try the shut the engine off trick on a back road tomorrow.

 

[TCluff]

save your self some hassle, before you put your truck back together, never seize all bolts, studs, and hub mounting surface to the spindle, it will be a lot easier the next time you have to take it apart... i have had mine apart a lot, and now i can change an axle u-joint in about an hour, i tend to break front axle u-joints from time to time, i will probably never grow up, 3rd gear 4hi launch in the mud broke the last one, actually it was yesterday... . oh well there is more at the store... . good luck.

 

[JStieger]

60,000 mile U-joints

Well... I jacked up the front end and pulled the wheels off. The right side axle shaft joint has about 1/4" of movement in the joint before the shaft moves. The left side joint has a hair of looseness to it.



I swear these u-joints are rated for 60,000 mile average life:



58,000 miles on the front drive shaft

61,400 miles on the rear drive shaft

62,000 miles on the axle shafts



I have spare u-joints already and I ordered up 2 wheel hubs in case I mangle my OEM on removal. I also started spraying everything with PB Blaster too.

 

[Slow Six]

The hub is easy to pop out. There are some previous threads that describe how to do it. An abbreviated version is to loosen the bolts that hold the hub in place. Place a socket with an extension on it and place between the bolt and the frame. Start the engine and turn the steering wheel. I did this and had no problem. Leave the axle nut on so that the hub cannot come apart. This procedure makes the axle a little heavier to handle but saves a lot of time and complications. I was able to do it alone but it would be easier with assistance. Also be careful to not get body parts in the wrong place while doing this. I think if you do a search on axle joints you should find all the info you need. I agree with you that all the joints in these trucks are designed to just make warranty. I am glad the after market had something as these joints from the dealer are stupid in price.

 

[JStieger]

This procedure makes the axle a little heavier to handle but saves a lot of time and complications.

Thanks for the advice! I'm a little confused by your description above though. Can you please clarify?



1) The axle nut is not undone at all?

2) So once everything pops free you can take the assembly to the workbench and undo the axle nut, replace unit hubs, etc. ?

3) Or do you change the u-joint only and then install the whole assembly back in as one?

4) Also, how much time are we looking at per side? I have some new shocks I'm going to install too!

 

[Slow Six]

1) The axle nut is not touched.

2)No need to remove or replace hub.

3)Yes.

4)In my case 2-3 hours per side. I am slow and this was the first time I had changed an axle joint. I also use anti seize on all surfaces as I reassembled. I had one u-joint fail shortly after installation and the second time was considerably faster. Shock installation is easy.

When I did the search before I changed the axle joints I seen that quite a few of the group used this procedure. There is a wealth of knowledge on this site which I find to be well worth the price of admission. Good luck and if you have more questions fire away and some one will have an answer.

 

[JStieger]

Thanks - makes a lot of sense now! Is the hub bearing pressed to the rotor? Or can the rotor be easily pulled off? I don't think my hub bearings are bad, but I am 50/50 on replacing them since I am in there already and with my luck if I don't do anything, they'll come up and bite me in the butt a week or so later...



I appreciate your answers to these questions - I have to drive 65 miles to my friend's shop to do this without having a spare vehicle so I want to make sure I have everything covered!

 

[TCluff]

Thanks - makes a lot of sense now! Is the hub bearing pressed to the rotor? Or can the rotor be easily pulled off? I don't think my hub bearings are bad, but I am 50/50 on replacing them since I am in there already and with my luck if I don't do anything, they'll come up and bite me in the butt a week or so later...



I appreciate your answers to these questions - I have to drive 65 miles to my friend's shop to do this without having a spare vehicle so I want to make sure I have everything covered!

i think it is easier to remove the axle nut, the rotor has a few cheasy keepers that hold it on the hub studs, they are of no importance so it is ok to leave them off, pull the two larger 18mm head bolts from the bracket that holds the bake caliper and remove it in one big piece, remove the rotor, remove the four twelve point bolts that hold the hub to spindle, remove hub but i leave the wheel speed sensor attached, set it on the ground, use a pry bar to get the axle started out, remove axle shaft, then change the u-joint, reinstall the same way, grease the splines and wear surface on the axle where the seal rides, it may sound cornfusing but is really simple, never seize all bolts because i guarantee this wont be the first time it will be apart... . i will be off on sat and sun if you need some help, i have factory service manuals if you want to do it by the book. .

 

[JStieger]

i will be off on sat and sun if you need some help, i have factory service manuals if you want to do it by the book. .

Thanks for the advice! The wheel hubs haven't shipped yet so it will probably be a couple weeks before I attempt the job - might have to give you a call!



Got the wheel hubs for $248 per side; list is $360 at Dale White Thanks for the internet!

 

[JStieger]

Got it done last night with help of a friend with a nice shop! Now I have all new greaseable u-joints on my truck within the last 1,500 miles!



The u-joint needles were nothing but powder. I did end up replacing both hubs since I was in that far anyway. Right hub was still good and free-spinning. The left hub was a bit stiff to turn. I'll just keep them as spares. The only setbacks were:



1) bent the thick plate puller from Quad 4x4 a bit. Other than this, the hubs took about 30 minutes per side to remove with a bit of heat and impact shock on the knuckle

2) had to reuse the old ABS sensors since the new ABS sensors that came with the hubs had different electrical connections on them

3) managed to round off one head of a caliper bolt so we ground the head a bit to accept the next size socket down. A few choice words thrown out by me in the meantime.



Before reassembly I used a paint stripper disk on the contact surfaces and applied liberal amounts of anti-sieze. Even though I don't live in the snow belt I was pretty surprised to see all the rust and corrosion all in 62,000 miles. I would hate to work on trucks from the NE!