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U Joint Replacement

75K views 59 replies 22 participants last post by  RChappo 
#1 ·
Hey All,
I need some help in replacing my U Joint. I have a vibration in my truck around 25-35 MPH. I've done everything else: alignment, yesterday got new tires and balancing, replaced hub bearing. Still have the vibration.

Anyway, my next step is to replace the U Joint. Anyone have a how to or pics? Pics would really help. How to is great too. I'm going to attempt it this weekend, please help.

PS: I already read this forum, good starting info, but I'm looking for more detail: http://forums.trailvoy.com/showthread.php?t=48927
 
#3 ·
What else could it be? :undecided

I had the passenger side hub and bearing replaced at 90K and I replaced my driver's side last weekend. Vibration was prior to this replacement. The driver's side was bad anyway, I thought it would cure the vibration as well, no luck.
 
#4 ·
I just replaced my rear axle bearings (95K miles and heavy trailer towing) and my rumble disapeared.

Could be u-joints also.

I'll have a write up with pics for the rear axle bearings, rear brake job, and a stuck spare tire winch in the next day or so.

U-joints are easy -- but hard work, i.e., mechanical ability is low, but it takes hammering or pressing, plus wrench turning. You can use a ball-joint press like this (OFTEN on sale for $29.95) or a full-size shop press if you have one, or again, just a hammer and a proper size punch or even a big bolt. Some times a big bench vise also works, especially for installing the new joint.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=38335

Start by removing the straps that hold the driveshaft in place. Pull the driveshaft. Test the u-joints by hand by simply turning the caps and moving the joint. It should be butter smooth. ANY hint of notchiness or drag and they are bad. Any sign of rust around the edges of the caps, same deal. Also, they should not flop, but rather take just a bit of force to move.

To remove the joint, pull off the two caps (with their bearing pins) and set them aside. Take a small torch (propane) and heat the two aluminum ears until the plastic locking ring squirts out of the holes, releasing the u-joint lock so it can be pushed out. Don't heat it any more than is needed to melt the plastic -- NOT red hot or you will ruin the driveshaft. Keep the torch moving and just warm it up. Push on one cap, using a press, or hammer and punch until you drive the opposite cap all the way out of the aluminum ear. Pull off the cap and bearing pins. Turn the shaft over and repeat, driving the other cap through the opposite side. Pull it, then remove the u-joint cross.

Replacing the joint is the same -- CAREFULLY, so as to not mess up the bearing pins, pull off the two caps that go into the ears of the driveshaft. Insert the cross, then place one cap into the bore. Make sure that the bearing pins stay all lined up! Press the cross into the cap, hold it there and drive the cap into the ear of the driveshaft. Tap the opposite side in place. Bolt it back into the car.

Here is a good article with a few pics:
http://www.automedia.com/U-Joint_Replacement/ccr20050301uj/1
 
#5 ·
I just replaced my rear axle bearings (95K miles and heavy trailer towing) and my rumble disapeared.

Could be u-joints also.

I'll have a write up with pics for the rear axle bearings, rear brake job, and a stuck spare tire winch in the next day or so.......
glfredrick, thanks so much for the write up. I actually found that automedia article this morning, I printed it out...doesn't say anything about a propane torch...;)

This is why it's good to get input from other members. OK, can't wait to see your other write up with pics.:tiphat
 
#6 ·
The plastic seal is sort of a new thing. You won't find that on most u-joint instructions. You can press the joint without melting the plastic, but it WILL be difficult and you run the risk of bending the aluminum ears on the driveshaft. Someone did that to mine (I was working on the front end and it was too late by the time I noticed.) now the joint is stiff on that side. It will eventually find its original shape, but the ear could have broken right off!

Oh, and the new joint will probably have a more typical spiral or e-clip to hold the caps in place -- MAKE SURE you install them according to the instructions in the u-joint box. If you spit out a cap, the joint and the driveshaft are junk.
 
#53 · (Edited)
The plastic seal is sort of a new thing.
They were new in the mid-1970s, maybe.

My friend whos a ASE, GM Tech and works at a GMC dealership said that he would never want to replace Ujoints on my trailblazer because you literally have to get the real deal cutting torch that uses ACELYTE or something like that with an oxygen mix that u could cut steel with and get the ujoint glowing red and then bang the **** out of it with a hammer till it comes loose
Which proves that ASE certification does not weed out ALL the idiots, just most of them.

i have a 08 trailblazer lt what is the strap on the u joint from side to side
what is the straps for
If it's the strap I'm thinking of, it holds the caps in place during assembly into the rear axle pinion yoke, so the caps don't fall off. Once the shaft is installed, that strap serves no purpose.





My 03 has 205K miles, for the last few thousand there's been vibration in the seat (but not in the steering wheel) at highway speed. There was a hint of vibration at 53 mph that went away by 55, then it came back at 68 and got worse with speed so that at 75 the rear view mirror was unusable because the mirror shook so bad I couldn't make out the image.

Wanting to not deal with this in my driveway at below-freezing temps, I drove to a shop and had them diagnose the problem. They had the vehicle two days, could not say for sure where the vibration was originating. When on the lift with the engine revved-up and in gear, the rear axle assembly shook, but the transfer case was smooth.

The wheels were balanced (no change) and they played games with the driveshaft balance using hose-clamps as repositionable weights, (no change). I took the Trailblazer home and put on my cold-weather gear. Four 7/16-hex-head bolts removed, driveshaft popped forward with a nudge from a prybar, then removed, and off to the local welding/machine shop with the shaft.

Three hours later, I get a call. They've replaced the two U-joints (front joint looked good, rear joint looked terrible. It's fairly common for the rear joint to fail before the front joint.) They put all drive shafts on a lathe, where they found that the shaft was bent about 0.040, they said they managed to straighten most of the bend back out. They found that the shaft was closer to balanced without the stock weight at the rear. They welded new weights front and rear to make it as good as possible. $100 for their labor, $21 for parts, I greased the splines, emery-clothed the rust from the rear-axle pinion yoke and straps, anti-seized the bolts, and gave it some loving torque to the fasteners.

Trailblazer is now totally smooth at 90 mph, in fact the truck is smoother now at ALL speeds, even though I hadn't noticed a problem with lower-speed vibration until it wasn't there any more.

Total Success!

I hauled the beat-up U-joint back to the shop so they could have a Teachable Moment.
 
#7 ·
When that time came for me (and my shaft was bent from kissing too many rocks), I just ordered a junkyard driveshaft. I think it was only $60 shipped, off Ebay. Took only ten minutes to install, a lot less time than doing the bearings. And if it only lasts a year or two, it will be because I've bent it again, not that the bearings are worn out. Not a tactic everybody will adopt, which is why I haven't posted before.
 
#8 ·
U-joints are not that hard, especially if you get one of those cheapy ball-joint presses. Makes it really simple.

Bent drive shaft is another story. i've seen them twisted beyond recognition on the trails.

I've replaced u-joints in almost every conceivable position, from hanging off rock ledges to the comfort of my garage with a nice 20 ton press at hand. Like the Nike commercial, just do it... :D
 
#9 ·
My friend whos a ASE, GM Tech and works at a GMC dealership said that he would never want to replace Ujoints on my trailblazer because you literally have to get the real deal cutting torch that uses ACELYTE or something like that with an oxygen mix that u could cut steel with and get the ujoint glowing red and then bang the **** out of it with a hammer till it comes loose
 
#10 ·
I jacked the car up and took some pictures. I need to mentally prepare before I take on a brand new project. I just did a little recon tonight and I will fix it this weekend. There's a little play up and down, nothing side to side.

It looks really rusty...if that's any indication.

Comments are welcomed.
 

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#12 · (Edited)
OK, I'll give it a go this weekend. Also the automedia pics are a little messed up. There's pics of the transmission in the mix...I think someone goofed.

I've replaced u-joints in almost every conceivable position, from hanging off rock ledges to the comfort of my garage with a nice 20 ton press at hand. Like the Nike commercial, just do it... :D
I believe you're lying. I don't remember you replacing U Joints in my driveway. Now if you want to correct yourself, my truck will be in the driveway.:D:D

Two more question: Once I take off the 4 bolts holding the u-joint in place. Do I slowly lower it down and then pull it out from the transmission (front of the car)?

This seems obvious, but I just want to be sure, I should replace the U Joints on both sides of the shaft, correct?

Last time I'll bug you until it's done then I'll show you pics...:thumbsup:
 
#13 ·
Yup. Pull the straps, then slide the slip joint out.

You will loose a small amount of oil. Helps to have the rear of the car raised some to hold it in better. Have a pan ready so you don't mess up the drive.

Oh, on the front joint, you don't have the luxury of just pulling off two caps like the rear. So, you just have to pull two sides of the u-joint instead of one. Same procedure, just have to do it twice up front.

I'll be around all weekend. Let me know if you get stuck. I'll do what I can from here... If you were close by, I'd prove that I'm not a liar, but oh well. Are you going to be at my place on Sunday to help set the body back on my rock crawler? :D
 
#17 ·
GM has been using plastic on the Ujoints for a LONG time.
A U joint can run dry an tighten up (then get loose).
Your vibration in the steering wheel?, or like mine in the seat at 72mph (roundabout). Don,t know if aluminum Dshaft is bent or Ujoints or something else. (I'll have to get around to that one...one of these days.):rolleyes:
 
#19 · (Edited)
The vibration is in the steering wheel highway speeds. Very mild vibration, but constant. When the truck is around 25-40 MPH then I can feel it stronger in the floor boards...both passenger and driver's side.

I'll replace the U-Joints, Passenger side front wheel bearing and see where I end up. If the autoparts store has the rear wheel bearing, I might pick that up as well and replace that.

I have 147K miles on the truck none of those parts have been replaced (except pass. side front wheel hub/bearing at 90K) and I don't mind throwing parts at it, since they're not expensive and it sounds like these will wear out, anyway.

Will keep everyone posted. I'm hoping to get it all done this weekend.
 
#18 ·
Like I said above, vibration could also be bad rear wheel bearings. I replaced mine last weekend and also replaced the oil in the rear axle with Amsoil -- totally removed my rumble. Bearings were worn to the point where they allowed the axle to move a bit. Nice and smooth now.

My vibration felt like tires were out of balance, and I even had them balanced -- again -- to no avail.

Write up on the way over the weekend when I have the time to load all the pictures and write the article.
 
#21 ·
If you feel it in the steering wheel at all, it's something in the front end... Could be a bearing or a tire out of round...
Mike
Yeah, I'm going to replace the front passenger side hub/bearing. I'll do this first. Then I'll look at the driveshaft U-Joints. I have 150 miles on the tires and it was vibrating before the new tires; I feel it less b/c I have tires with more than 2/32 of tread now. :yes: Vibration is very mild, but constant.
 
#24 ·
I can't seem to "slide" the shaft forward. Is there a trick to this?

It's all rusted in the rear. I took off the two metal straps, and I gave it some force, but it's difficult when you're laying on your back.
 
#27 ·
I can't seem to "slide" the shaft forward. Is there a trick to this?
Is it not seperating from the yoke? If not soak it in penetrating oil overnight. I tried on mine when replacing the axle and it wouldn't budge. Soaked it a few time and a few days later it came out like nothin.

If its free but has no room to move then do as roadie says and support the frame and let the axle sag a bit.
 
#25 ·
If you let your differential hang down while supporting the frame, get a floor jack under the pumpkin and lift it a bit. Might give you more room to slide the shaft forward. If the pumpkin is raised, then support the frame and drop it. Basically whatever position the pumpkin is in, change it.
 
#29 ·
Actually, you are describing a normal u-joint fit. If it just slid out, your driveshaft would be worn to the point where it needed replacement.

Just stick a pry bar between the cross of the rear u-joint and the yoke on the axle and give it a sharp pull or two. It will come out. You won't tear up anything. You can also use a brass hammer to give a few sharp blows to the SIDE of the yoke (toward the u-joint cap) which will also loosen things up. I prefer the pry bar (big screwdriver) method. Just stick it in there and pry away.

There is always enough room to slide the front shaft inward -- if not, then you have something FAR out of the ordinary and run the risk of damaging your transfer case or transmission, but I fully expect that with a stock setup, you won't find the front to be the issue.

You'll find that you have about an inch of slide up front, which is normal, and it will slide up there VERY easily. Your point of sticking is where the cups of the u-joint are tight against the small ears of the yoke -- as I said above, a perfect fit. The new joint will also "pop" in between these ears with some amount of effort -- typically when you tighten the straps and pull it in. Just make sure it is centered.

Once you actually get the driveshaft out, you will see what I mean by the little "ears" on the yoke. They serve to locate the u-joint side-to-side.
 
#30 · (Edited)
Ok did everything. But now rumbles/shakes. I know I put everything back the right way cause I marked it with a pen. No noise though any ideas?


Edit: I removed the driveshaft again and took out the u-joints towards the rear of the vehicle. I rotated them 90 degrees (basically putting the other two caps through the u-joint). I really took my time to make sure everything was even as I possibly could get it. I then reinstalled it and noticed that I wasn't tightening the straps tight enough. I bought new straps and they aren't "molded" to the new caps. So after i thought it was tight the strap still had some play in it. I really tightened the bolt and I could see the strap settling more and more down. During this process I also made sure the u joint was as even as possible in the thing that holds the u joints, again towards the back of the truck.

This fix did not solve my vibration problem, I'm taking it to the dealer on Monday for a leaking TC (should be under warranty) and going to tell them there may something else wrong with the transmission for that noise or the rear diff. If it's there, they might as well check it.
 
#32 ·
Glad it worked out. I'm thinking that you finally got the rear straps tightened all the way, which removed the shakes. :yes:

I was working on a somewhat more involved project today... Got the body back in place on my rock truck. :thumbsup:

Lots of work left to do on the truck, but at least the suspension is finished enough to drop the new cab on the frame and start re-assembly. I'll get to make my new driveshafts... :tiphat

 
#35 ·
universal joint replacement.

Marked driveshaft position with a sharpie. One strip on the diveshaft and one on the yolk. Unbolted rear driveshaft. Used small propane torch on it for a minute or two. Then I used a pry bar, it came right off. Went to Advance Auto Parts.Put a deposit down on the ball joint press. I just used the clamp no attatchments. This was after torching the ears of the driveshaft to loosen up the factory inserts You're gonna need a BFP and a 7/8 BFW. turn that till BAM! You're home free. Forget bangin' on that. You need a press .Used vice and socket method to reinsert new joint. Place a cap in each hole. Not all the way in. Then insert x. Make sure zerk fitting is facing forward, towards the engine.You have to grease this fitting. Make sure those bearings in the caps are all standing up. Insert in vice w/socket and press. Dont forget to insert locking rings on all 4 caps!! I just did 2, the 2 caps in the ears, and she wobbled badly down the road. Inserted the other 2 locking clips and it centers it in the rear end. Just tighten down on the clips in the back and @ 80 m.p.h. Victory!! This is the first one I ever have done and this was quite nerve racking. Thinking the whole time I am so gonna need a new driveshaft! Thanks for all the info I've collected and used on this site! Just thought I would return the favor.:woohoo::hail::thx
 

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#43 ·
Marked driveshaft position with a sharpie. One strip on the diveshaft and one on the yolk. Unbolted rear driveshaft. Used small propane torch on it for a minute or two. Then I used a pry bar, it came right off. Went to Advance Auto Parts.Put a deposit down on the ball joint press. I just used the clamp no attatchments. This was after torching the ears of the driveshaft to loosen up the factory inserts You're gonna need a BFP and a 7/8 BFW. turn that till BAM! You're home free. Forget bangin' on that. You need a press .Used vice and socket method to reinsert new joint. Place a cap in each hole. Not all the way in. Then insert x. Make sure zerk fitting is facing forward, towards the engine.You have to grease this fitting. Make sure those bearings in the caps are all standing up. Insert in vice w/socket and press. Dont forget to insert locking rings on all 4 caps!! I just did 2, the 2 caps in the ears, and she wobbled badly down the road. Inserted the other 2 locking clips and it centers it in the rear end. Just tighten down on the clips in the back and @ 80 m.p.h. Victory!! This is the first one I ever have done and this was quite nerve racking. Thinking the whole time I am so gonna need a new driveshaft! Thanks for all the info I've collected and used on this site! Just thought I would return the favor.:woohoo::hail::thx
thanks for the write up.:thx i will be doing my u-joints this weekend
 
#37 ·
When I'm under my truck when its turned off, the driveshaft spins both ways from neutral point, not entirely, but there is play in it. Is it supposed to be solid all the way around? What about just grabbing it and trying to shake it?
 
#38 ·
Anyone shed some light on my previous post? Also, what material is our driveshaft made of? Is it solid or is the outermost part just a cover? When I tap on it, it has a hollow, almost plastic-like sound.
 
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