Is my CV joint gone bad??

I have a '76 manual 3 speed in my Bronco, it does have the Dana Splicer driveshaft in it.
Here is my problem...Coming home tonight I noticed when in gear and releasing the clutch I was getting a 'bump' 'bump' which sounded like it was coming from my transmission. The bump got quicker the faster I went down the road and putting it in neutral and coasting down the road the noise stops. I couldnt really feel a vibration like a u-joint does and honestly was worried I have some gears going bad in the tranny. BUT I do have a Twin stick installed in it. After I got home, I locked in the hubs, put it in 4 wheel drive and put my rear end in neutral. No noise...4 Hi or 4 low (with rear end still in neutral) no noise. I crawled under it tonight with bad lighting and shook the driveshaft but didn't see it twist and move like a bad u joint would do but I have no experience with the CV joints. I plan on taking out the rear drive shaft Friday to do a better inspection. What do I need to look for?? Maybe I have something else wrong?? Any test I can do??..And this CV joint looks kinda tough to replace, can it be done with a vice like any other u-joint?? Thanks for any help, was hoping to go mudding this weekend so want to get this right...

Have you ever greased it? If not, that could be the problem, but as long as the driveshaft turns it will have a vibration. Unbolt the driveshaft from your Bronco so it’s easier to inspect, you should then be able to tell if that’s the problem. There is a small round fitting that takes a needle style grease fitting that you grease. I’ve attached a pic that shows the ball, socket and small fitting. The ball and race is replaceable for those of us (me) that don’t grease it.

Was the d-shaft under load when you checked it? Sometimes when parked in gear it will take up any slack & make a loose u-joint seem tight.

ScanmanSteven said:

Have you ever greased it? If not, that could be the problem, but as long as the driveshaft turns it will have a vibration. Unbolt the driveshaft from your Bronco so it’s easier to inspect, you should then be able to tell if that’s the problem. There is a small round fitting that takes a needle style grease fitting that you grease. I’ve attached a pic that shows the ball, socket and small fitting. The ball and race is replaceable for those of us (me) that don’t grease it.

Click to expand...

No I have never greased it. So in the pic it looks like I have to take the u joints out before I can get to the grease fitting??....If the race is bad will I be able to tell my looking at it and would that cause my vibration problem??..Sorry for all the questions, like I've said I have never messed with CV joints..

And to answer you question I did have it in neutral when I checked movement...

It's not actually a CV.

Some double-cardan (DC) joints have a centering ball that's sealed. That means the whole assembly has to come apart to add grease. Some have a needle-type grease fitting that requires a needle on your grease gun. Those can usually be reached with the driveshaft installed, or by simply unattaching one end of the driveshaft to flex the joint so the fitting is exposed. Others may have a common Zerk, or a remote grease fitting & a journal that carries grease to the ball.

Look at the bottom of this diagram (on a computer monitor - not a phone):



But if the ball is already binding or loose, no amount of grease will fix it. That kind of problem usually propagates to the u-joints quickly, requiring a complete teardown & rebuild.

Thank you. I went ahead and took driveshaft out. The actual u joints dont look or feel bad but the center yoke (according to the diagram above) does not rotate very well. It has tight spots in it and it appears to be not in the best shape. I have to put a good amount of pressure on it to make it swivel. I will attempt to take u joints out tomorrow. But if I need this 'yoke' does any body know the part number or something that my local parts store can order it for me and get it to me?? Of can I just run it until it comes in?? I know it will 'knock' a little but will I do any more harm if I keep driving it??

Phrases I have heard in the past:

Looks way to dry in there for me, IMO you need to fix it and not drive it till you do.

And that knock is a sound of something that is not right, so repair accordingly. Driving it usually only makes it worse and more expensive in the end.

Sure drive it and maybe ruin other things that it connects to, I mean its only money right?

And that can mean things are out of balance and that can cause other issues with seals and other good u joints. Important seals like out put and pinion seals...

There is something flat that looks out of place at the centering ball. Just above the left grease seal in the picture. I'm trying to pull memory and apply it to a 3D problem with a 2D picture and it isn't working right.

Broncobowsher said:

There is something flat that looks out of place at the centering ball. Just above the left grease seal in the picture. I'm trying to pull memory and apply it to a 3D problem with a 2D picture and it isn't working right.

Click to expand...

It looks like the ball has come apart, from the joint.

Broncobowsher said:

There is something flat that looks out of place at the centering ball. Just above the left grease seal in the picture. I'm trying to pull memory and apply it to a 3D problem with a 2D picture and it isn't working right.

Click to expand...

That is the metal flange that used to have a rubber boot attached to it. The factory drivelines came with "sealed" centering yokes. The boot was to keep crud out and the little bit of grease in. You have to disassemble the whole joint to replace them. The boots are only $5 and the centering ball can be replaced much cheaper than buying a whole new centering yoke. You can also change over to the greaseable yoke and not worry about it as the boot isn't necessary and won't fit the greaseable joints.

I talked to my local Ford/Bronco guru and explained to him what the 'CV' joint was doing, and he says its normal for it to be hard to move. But I do agree it looks like something is aloose in the picture.
But my friend says to put rear shaft back on and take FRONT driveshaft off and see if noise goes away. He explains sometimes the hubs will make the front drive shaft rotate and maybe put some back pressure on the transfer case. Going to try that in the morning to see what happens. If this thing is messed up how do I fix it??...Went to my local parts store on the way to work and when I explained to them what I wanted they looked at me like I had a booger hanging out of my nose.

Here is an example of the boot. Most of the time they are missing from age or in a lot of Broncos case running too steep an angle on the driveshaft.

http://www.dennysdriveshaft.com/p10..._rubber_boot_for_ford_oem_non_greaseable.html

kat said:

If this thing is messed up how do I fix it??...

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Take it to a local driveshaft shop and have it replaced.

I grease mine religiously (every oil change) and I still only get 15-20K miles out of them due to a slightly higher-than-stock rear driveline angle.

Todd Z.

broncodriver99 said:

Here is an example of the boot. Most of the time they are missing from age or in a lot of Broncos case running too steep an angle on the driveshaft.

http://www.dennysdriveshaft.com/p10..._rubber_boot_for_ford_oem_non_greaseable.html

Click to expand...

I do have a 3 inch lift but the angle of the driveshaft isn't bad...the suspension lift helped with that.
So maybe you missed my previous post but is the joint suppose to be loose or stiff?? Because it's stiff right now. If I do have to take the ujoints out do I just slap some grease on it and put a boot over it???

toddz69 said:

Take it to a local driveshaft shop and have it replaced.

I grease mine religiously (every oil change) and I still only get 15-20K miles out of them due to a slightly higher-than-stock rear driveline angle.

Todd Z.

Click to expand...

Local driveshaft shop??...That is over an hour away, close to the Wal Mart if there is one....=)
How do you grease yours Todd?? You have one that has a fitting??

kat said:

I do have a 3 inch lift but the angle of the driveshaft isn't bad...the suspension lift helped with that.
So maybe you missed my previous post but is the joint suppose to be loose or stiff?? Because it's stiff right now. If I do have to take the ujoints out do I just slap some grease on it and put a boot over it???

Click to expand...

The angle may not be bad but it may still be beyond what the joint was designed to do which will cause it to wear faster. There should be a little resistance but I wouldn't say it should be stiff. Without disassembling it for inspection it is hard to say. There are extremely small needle bearings in there that will need to be checked. I have seen a couple of joints where the needle bearings were completely gone/missing, likely just ground to dust from being dry. If everything is still there and in good shape yes you can just grease everything and replace the boot, if not you can buy just the centering ball and seal and rebuild the yoke with a few tools and some patience, Neapco and Rockwell both make them. Make sure to check the centering pin that the yoke slips onto for wear as well. You can also just upgrade to the greaseable joint so you can service the joint without disassembling the driveshaft. I do recommend the Spicer grease as it is synthetic and a long life grease with drivelines in mind. It will hold up better than standard "chassis lube". You should probably have a look at your front driveshaft as well, it is likely in similar condition.

I have a 3.5 inch lift and my joint is the same one that came in the bronco. I do grease it at every oil change. mine has a needle jert and my gun has a needle on it.I do disconnect it from the transfer case to make it easier.

savage said:

I have a 3.5 inch lift and my joint is the same one that came in the bronco. I do grease it at every oil change. mine has a needle jert and my gun has a needle on it.I do disconnect it from the transfer case to make it easier.

Click to expand...

AFAIK they all came with sealed joints from the factory. Someone may have worked on that driveshaft at some point who knows. I had a '72 that had a sealed joint in the front shaft and a greaseable joint in the rear shaft. Out of curiosity which was correct I pulled the Bronco BOMs from the spicer website and they all showed sealed joints.

savage said:

I have a 3.5 inch lift and my joint is the same one that came in the bronco. I do grease it at every oil change. mine has a needle jert and my gun has a needle on it.I do disconnect it from the transfer case to make it easier.

Click to expand...

That's exactly what I have and what I do with mine.

Todd Z.

To answer one of your questions, NO, it should not be tight or hard to move. Yes it's "awkward" to move because it wants to flop around, but it should be smooth and easy to move.
You should be able to make it flop all over the place with little effort other than what it takes to lift it's not insubstantial weight.

With these types of shafts (yes, a double-cardan is actually the first original CV setup from over 600 years ago if I remember) you will not always get a vibration. I've been involved with diagnosing many of them and almost none of them acted the same as the previous one.
Sometimes you get noise, sometimes you get vibrations, sometimes you get both. And most of the time the noise or vibration is not the one you remember from the last one you experienced.
Or from the one that others have experienced. Very easy then to mis-diagnose a failed yoke or cross.

You can also remove the rear shaft and drive on the front to eliminate the rear from the equation. That seems to me to be the better of the two methods because the front lightly spinning is rarely a problem.
And if it is causing trouble, you have other problems! A front driveshaft will often spin slowly while driving. Not from the front hubs dragging (that would be another problem still!) but more from hydraulic resistance/friction turning the front output components of the transfer case.
Of course if the front hubs are locked in, you will get spinning at full speed and maybe more noise than normal. But not a vibration usually.

Here are the ones we offer: https://www.wildhorses4x4.com/category/Early_Bronco_Driveshafts starting at $259.
We still have the front yoke for the CV head, but not (apparently) the centering yokes anymore. That's the big part that holds it all together. So what we have is only part of what you need if yours is totally worn out.
If it turns out to be only the front yoke of the CV head though, that one part (#8593) could be all you need.
At this point though I'd be tempted to replace the whole shaft if you see other wear and tear on yours.

But it's obviously more money to do so. Worth it if you need a new one of course.

Good luck.

Paul