New AX15, very chirpy but not the TOB

[brucecooner]

Back in April (4-5 months ago now) I got a brand new AX-15 into the Jeep.

I acquired it from Novak, but no way I could do it myself, so I went with a shop that does pretty good work (but a couple of things were like, hmmm).

 

The throwout bearing started chirping right away, but the guy from Novak said basically "some Jeeps do". Ok.

I've tugged on all the u-joints and they're all nice and tight, nothing is slipping there (though that would be a clunk more than a chirp I guess).

 

The bearing has gotten quieter, but a different chirp has started that definitely isn't the TOB.

 

You hear this once you get it up to or above 10-15 mph, and this chirp is tied to the wheel speed and not engine speed.

Once you're at speed, you can clutch in and coast, and the chirp continues.

Disengage the clutch and shift through all the gears, still chirping.

No matter the state of the selected gear or the clutch, you hear this chirp.

As you coast to a stop, the chirp slows with it, disappearing below about 8mph, it seems driven by wheel speed alone.

 

It sounds like it's coming from just behind the shift lever, BUT I left the plastic cover and boot off for now because they don't fit over the new lever, so I'm hearing sounds from all over the underside.

 

Today I put it up on jack stands so I could at least remove the front drivetrain from the equation and, there's no chirp at all.

In 2H I can run it up to third gear, 25-30 mph, and I don't hear the sound, when I definitely was hearing it on the road.

I put it in 4h, to get the front drivetrain turning again, but there was still no sound.  Put the TC in neutral, still no sound.

 

I did lock the front axle CAD just before the transmission install, so who knows how long everything up front had been static before the install.

I was hoping maybe something in the front driveshaft or system was noisy, but I can't really say that's the case (the chirp was not heart in 4H).  And like I said, the front u-joints are nice and tight.

 

Anyway whatever the sound is, it ONLY seems to be happening when the system is under load.

That says u-joint or other power transmitting point to me, rather than a bearing, but I'm no expert.

 

I do have a slow seep from the transfer case drain plug, so I checked that after turning off the Jeep and it shows to be low, BUT I was just running it so I suspect the missing fluid is just up in the chain/gears.  Going to check it again later and besides, it wasn't chirping on the stands so I doubt the fluid is an issue. (EDIT: I waited a while, the fluid drained back down and it's barely below the drain plug now).  

 

EDIT: I went on an errand and came back and put it through the paces again.  The throwout bearing chirps like a coke addled canary sometimes, but the other sound is, again, nonexistent. I ran it with the TC in every stop too, 4H, N, 4L, no sound.

 

Anyone else ever have something chirp under load that seems totally unrelated to the clutch?

 

 

[M.T.Hands]

dry u-joints will chirp, I know you mentioned they feel tight, but the first sign of u-joint trouble for me outside of total failure was a squeak when vehicle is/was in motion, If the frequency stays the same or increases/decreases with speed tells me it is something consistent with a part that is turning (drivetrain) if you have serviceable u-joints I'd try loading them up and make sure that grease is going completely through the joint 

 

I have had zerk fittings on tractors and equipment that would not take grease, it's an easy check and not expensive

 

 

 

[brucecooner]

3 hours ago, M.T.Hands said:

dry u-joints will chirp, I know you mentioned they feel tight, but the first sign of u-joint trouble for me outside of total failure was a squeak when vehicle is/was in motion, If the frequency stays the same or increases/decreases with speed tells me it is something consistent with a part that is turning (drivetrain) if you have serviceable u-joints I'd try loading them up and make sure that grease is going completely through the joint 

 

I have had zerk fittings on tractors and equipment that would not take grease, it's an easy check and not expensive

 

 

 

Interesting.  Like I mentioned, I have the shift lever boot off right now, so I'm getting an earful of stuff I don't normally hear, and I might be hearing a u-joint very early in its death throes that I'd never know of with everything buttoned up.

 

These joints were on there when I got it almost three years ago, at 188K, so I can't say how old they are.  They definitely don't look very fresh, covered with a good layer of caked on dirt, which may be a sign they're running dry.

Definitely worth a look, I'd be happy if it is just u-joints chirping.

[brucecooner]

From what I can tell, I need series 1310's for both front (D30) and rear (D44) shafts, but there are 3 in the front (it's double jointed at the TC), for 5 in total.

 

I can't get a clear reading on the front though, are all 3 of the front shaft 1310's?

 

 

[ghetdjc320]

1 hour ago, brucecooner said:

From what I can tell, I need series 1310's for both front (D30) and rear (D44) shafts, but there are 3 in the front (it's double jointed at the TC), for 5 in total.

 

I can't get a clear reading on the front though, are all 3 of the front shaft 1310's?

 

 

That’s correct but there are two types of joints, one for driveshafts and one for steering axles. Both have the same cap diameters. The driveshaft ones are spicer/dana part number 5153X. They are all the same for all driveshaft joints

[gogmorgo]

If you’re changing the ujoints in the CV for the front driveshaft, get the centring ball for it too. The ball on its own is Dana part number 10018465 or for not a lot more money you can get the whole centring yoke with the ball in it, 211355X.

And yes for ujoints the Dana 5153X imo is the best option out there, as long as you grease them.  I’ve used others in the MJ and never had them fail, but we run 1310 shafts for the crank-driven PTO shaft for the hydraulics on our plow trucks. The Dana u-joints have a nice meaty cross where the grease nipple is and are easier to get a grease gun into than the others. In that application this was critical because not getting grease onto them meant they seized up within a few months and then they’d experience catastrophic failure. And I don’t think I need to tell you how much carnage can be done by an 18” piece of steel being whipped around by a 15L diesel engine. 

[brucecooner]

On 9/23/2024 at 10:24 AM, gogmorgo said:

If you’re changing the ujoints in the CV for the front driveshaft, get the centring ball for it too. The ball on its own is Dana part number 10018465 or for not a lot more money you can get the whole centring yoke with the ball in it, 211355X.

And yes for ujoints the Dana 5153X imo is the best option out there, as long as you grease them.  I’ve used others in the MJ and never had them fail, but we run 1310 shafts for the crank-driven PTO shaft for the hydraulics on our plow trucks. The Dana u-joints have a nice meaty cross where the grease nipple is and are easier to get a grease gun into than the others. In that application this was critical because not getting grease onto them meant they seized up within a few months and then they’d experience catastrophic failure. And I don’t think I need to tell you how much carnage can be done by an 18” piece of steel being whipped around by a 15L diesel engine. 

An engine that big could whip around a shoestring and do some damage.

 

I went ahead and got the complete centering yoke and a fistful of 5153X's.  I don't know how old anything is under there so might as well freshen it all (if the darn weather ever cools off here).

 

I do have another question. 

There's a telescoping connection in the rear driveshaft, closer to the front (TC end), with a grease fitting on it.

Obviously it expects to be greased, but is there anything in that connection that would ever need service or replacing?

[gogmorgo]

14 hours ago, brucecooner said:

 

I do have another question. 

There's a telescoping connection in the rear driveshaft, closer to the front (TC end), with a grease fitting on it.

Obviously it expects to be greased, but is there anything in that connection that would ever need service or replacing?

The factory rear driveshaft doesn’t have this. It has a slip yoke in the transfer case tailhousing. 
Its likely you’ve got a slip yoke eliminator setup. It’s less critical with the MJ’s longer driveshaft but on a shorter wheelbase Jeep with enough lift you might have enough travel in the slip section as the axle moves up and down to pull a slip yoke too far out of the transfer case. Similar to the front driveshaft. It’s also sometimes done to help with driveshaft angles. Usually you’d see it with a full CV like the front shaft, but not always.
There’s a few different outfits that produced them, there’s also a couple common DIY methods, and plenty of driveline shops custom building things. It’s tough to say what you’ve got without knowing. 
But in general there’s not much inside the sliding section. There’s usually a seal on the female end, but other than that you’re really just looking at greased splines sliding in greased splines. Not necessarily the worst idea to pull it apart and clean any debris out of there that might have worked its way in, but if it’s been kept well greased and the seal’s in okay shape it’s not usually a huge concern. 

If for whatever reason you do decide to pull it apart, mark the alignment so it goes back together the same way. You don’t want the driveshaft U-joints going out of phase or you’ll get some hellacious vibrations. Although if it does come apart on you and it’s not marked, it’s easy enough to line the ujoints back up. Just drop the shaft on a flat surface and make sure the u-joint caps are both sitting flat. 

[brucecooner]

8 hours ago, gogmorgo said:

The factory rear driveshaft doesn’t have this. It has a slip yoke in the transfer case tailhousing. 
Its likely you’ve got a slip yoke eliminator setup. It’s less critical with the MJ’s longer driveshaft but on a shorter wheelbase Jeep with enough lift you might have enough travel in the slip section as the axle moves up and down to pull a slip yoke too far out of the transfer case. Similar to the front driveshaft. It’s also sometimes done to help with driveshaft angles. Usually you’d see it with a full CV like the front shaft, but not always.
There’s a few different outfits that produced them, there’s also a couple common DIY methods, and plenty of driveline shops custom building things. It’s tough to say what you’ve got without knowing. 
But in general there’s not much inside the sliding section. There’s usually a seal on the female end, but other than that you’re really just looking at greased splines sliding in greased splines. Not necessarily the worst idea to pull it apart and clean any debris out of there that might have worked its way in, but if it’s been kept well greased and the seal’s in okay shape it’s not usually a huge concern. 

If for whatever reason you do decide to pull it apart, mark the alignment so it goes back together the same way. You don’t want the driveshaft U-joints going out of phase or you’ll get some hellacious vibrations. Although if it does come apart on you and it’s not marked, it’s easy enough to line the ujoints back up. Just drop the shaft on a flat surface and make sure the u-joint caps are both sitting flat. 

I swear, some days my brain ain't with me.  It's been a while since I was under there, but crawled under again this evening to take another look, and that telescoping connection is on the FRONT driveshaft, not the rear.  My memory was turned around 180 degrees.

I'm guessing this is a stock arrangement.

 

And I'd guess the same advice applies to the telescoper, check it and/or grease it.

 

I took another look at the centering yoke though. 

Dang thing is well buried above the trans mount.

Looking at it, I can't figure out if you're supposed to just remove those four bolts on the TC side, or if you disconnect the front (axle end) joint, then pull the shaft out of the TC, bringing the yoke with it.

 

 

I haven't seen a good guide for removal/replacement/resintall of this end either.

If anybody knows of a clear set of instructions out there, I appreciate any pointers.

 

And thanks gogmorgo for all the info.

 

 

 

 

 

[89 MJ]

The front driveshafts do not have a slip yoke, so you’ll have to pull the four bolts at the axle and the other four bolts at the transfer case. 

[gogmorgo]

Yeah the front shaft is not the nicest thing to remove. You unbolt the driveshaft from the flange on the transfer case, which wouldn’t be such a big deal except for there’s very tight clearance for getting onto the bolt heads, and they tend to have not moved for a long time which means they don’t want to.

I think it’s a 5/16” hex head, if memory serves. The box end of a wrench is the easiest thing to get on there but if you don’t have a very good fit on it they’ll want to turn into circles. I’m nervous even using a high-end 12-point wrench. 6-point wrenches are getting difficult to find, but it’s the one of the few places I’d want to use one. And it’s not a great spot to get heat onto to help loosen them. 

[Eagle_SX4]

I have had good luck using a 6 point 5/16" 1/4" drive socket with a wobble extension for the front pinion bolts. I think the transfer case side bolts have 1/2" heads and you can use a 1/4" drive socket on those as well. You will just need to rotate the driveshaft to get to all of them.

[pizzaman09]

When you reinstall the front driveshaft, make sure you remember to actually torque the bolts.  I'm very lucky I didn't make a huge mess out of the bottom of my truck when the front u joint straps came off and the drive shaft, pointing forward was lightly bouncing off the ground as I drove it around.  

 

A great tool for the little bolts is a ratcheting box end wrench.

[brucecooner]

Thanks guys all for the pointers.  I'm thinking I should put some penetrant on the bolts a day or so before I decide to turn them.

 

On 9/27/2024 at 1:09 PM, pizzaman09 said:

When you reinstall the front driveshaft, make sure you remember to actually torque the bolts.  I'm very lucky I didn't make a huge mess out of the bottom of my truck when the front u joint straps came off and the drive shaft, pointing forward was lightly bouncing off the ground as I drove it around.  

 

A great tool for the little bolts is a ratcheting box end wrench.

Good to know!  Do you happen to know the torque rating on those guys?

 

 

I got the new joints the other day.

One of the u-joints had partially self-disassembled in the box.

Thankfully the grease kept the pins inside the cap.

 

My son, who is way more of a wrench turner than I am, grabbed it from me immediately and took it to the garage where he keeps his pick set, and returned a few minutes later reporting that all the needles were there.  Which is what I would have done, but he loves to help while he waits for his Ford small block rebuild to get done.

Anyway, I suspect this isn't an unusual occurrence for these caps and the grease probably keeps them from falling out, usually.

 

What I found more concerning was the centering yoke did NOT arrive wth the little plastic protector cap I've seen in some install guides.

I think the only thing in there is the spring, which is clearly still there, so I don't think it could be missing any parts. Probably.

 

Anyway, my son and went out this evening to grease the existing joints to see if it would quiet  them down, and to maybe pinpoint this as the problem, and we found out the front yokes don't have enough clearance between them to get a grease gun onto the fitting.  Argh.

We could do the slip joint in the front shaft, but couldn't get to any other fittings.

He remarked that the centering yoke has a different fitting (not zerk) and that made me remember that the new one does has a different fitting.

He said it must be a needle(?) style.

 

Anyway, we greased every fitting we could reach (rear driveshaft, front ball joints, steering, etc.), then took it out for a drive.

The angry sparrows are even louder now lol.  We really made them angry.

As we were UNable to grease any front joints, I'm not surprised, and this probably rules out the rear joints (which are still getting replaced anyway).

We moved our heads all around the cab and determined it really does sound like it's coming from the driver side floorboard too.

 

After this evening I was left with a couple of questions though...

 

The front u-joints are practically un-service-able in stock form, unless you pull the shaft off I guess, at least my son's conventional grease gun end would NOT fit between the yokes.

Is there a special skinny adapter you can get to allow you to snap onto a fitting in a tight space?

Can you pre-install needle style grease fittings on the u-joints and then gain the ability to service them that way?

Or is it better to put non-serviceable joints on the front and let 'em ride?  I'd much prefer serviceable parts.

 

Also, can you drive a Jeep without the front driveshaft?

 

If I pull the front shaft (four bolts at each end) and run it in 2H only, to see if those birds are FINALLY quiet, would it shake anything loose?

I'd like to just pull the front shaft and drive it around and see if the noise is gone.

Probably pointless, of course, I already have the parts, but I don't have long stretch of time to fiddle with it, and it would be nice to finally know ah-ha! it was the front shaft all along.

 

[Eagle_SX4]

Driving without a front driveshaft won't cause any damage. Doesn't matter what the transfer case is in either. The front output will spin in 4wd but won't harm anything. Just leave all the bolts for the drive shaft out and you will not have any issues.

[pizzaman09]

I don't know that actual torque values for the u joint straps.  My issue with them coming loose was that I had only finger tightened them and never came back with a wrench to finish the job.  It happened after we spent 4.5 hours attempting to get the darn pilot bearing aligned installing the transmission so we were not in a clear state of mind.  

[gogmorgo]

I don’t know what actual torque spec is on them. I’m sure you could look it up if you wanted to know. I usually just tighten them back down good with whatever tool I used to remove them. You don’t want them to back out but remember they are small fasteners so you don’t want to overdo it.

There is a variety of other adapters out there. I’ve used one that’s like a long thin tube that just barely fits over the nipple that’s good for tight spots.

I’ve seen needle style grease gun fittings too, like a needle for inflating basketballs, although I think I’ve mostly seen them used for pushing around a boot for a ball joint, which I think is of questionable value, because you’re not really putting the grease onto the bearing surfaces. 

There’s another common enough fitting in ujoints, typically to go in the cap (not the cross) for low clearance areas, where you might risk snapping it off. It’s a bit of a shallow cone. There are specific grease gun adapters to fit those, basically the same shape but opposite.

 

But that brings up a couple good points. It’s good to make sure you orient the grease fittings in a way you can get at them. I had a one-ton on the hoist yesterday where I couldn’t grease the rearmost driveshaft ujoint because it was installed with the nipple pointed straight at the pinion yoke. If it had been flipped around and pointed facing the shaft it wouldn’t have been an issue. 
One other less critical point, it’s nice to line up all the nipples along a shaft so they’re all pointing the same direction. It doesn’t improve function at all, but it makes it quicker to find them when you’re greasing them, instead of being pointed in random directions. 

[brucecooner]

Progress has been slow.

The daily high temperature shot back up to the 110's a couple weeks ago, making laying on the driveway in the evening like laying on a bed of hot coals.

 

I finally had an afternoon to myself yesterday, and the temps have backed off a little (low 100's in the afternoon) so I got back under there and

went after the bolts on the front driveshaft. 

 

The front caps were easy enough to free but man, those rear bolts at the TC are well defended.

I think I'm being punished for daring to have the transmission swapped, as that put the new crossmount in just the right place to keep me from going perpendicularly at the bolts.

I do have a quarter inch drive wobble extension, but not a half inch socket with integrated wobble.

Fortunately I just happened to have this 90 degree bar attachment in the box of socket cast offs my dad left me decades ago.  He's long gone but still helping me out.

The bolts were put in not that long ago when I had the transmission swapped so they were easy to turn once I was able to get a socket on them.

 

It was straightforward to remove once all the bolts were out.

 

 

The jack held it in place while I unbolted it so it didn't crash down on my head, the string was my comically inadequate attempt to ensure the shaft didn't separate at the telescoping joint when one end invariably fell off the jack.  The joint is way too sticky to come apart without some applying some elbow grease though, and I had the shaft in control the whole time.

 

Of course, the first thing I did was to test drive the Jeep, and YAY the angry chirping bird is gone!

 

There's a tiny chance it was the front output side of the transfer case making the noise, since it is no longer being turned by the shaft, but

I'm more inclined to think it was the 35 year old dry as the desert joints in this shaft that were the source of the noise.

 

Anyway, I had forgotten how much I enjoy driving the old rattletrap, and my test drive turned into an extended pleasure cruise around my corner of the valley.

So now I can drive it without worrying about something in the drivelines seizing up, as long as I don't need four wheel drive, and I can rebuild this thing somewhere inside, where it's not 110 degrees.

 

 

 

 

[brucecooner]

26 minutes ago, gogmorgo said:

I don’t know what actual torque spec is on them. I’m sure you could look it up if you wanted to know. I usually just tighten them back down good with whatever tool I used to remove them. You don’t want them to back out but remember they are small fasteners so you don’t want to overdo it.

There is a variety of other adapters out there. I’ve used one that’s like a long thin tube that just barely fits over the nipple that’s good for tight spots.

I’ve seen needle style grease gun fittings too, like a needle for inflating basketballs, although I think I’ve mostly seen them used for pushing around a boot for a ball joint, which I think is of questionable value, because you’re not really putting the grease onto the bearing surfaces. 

There’s another common enough fitting in ujoints, typically to go in the cap (not the cross) for low clearance areas, where you might risk snapping it off. It’s a bit of a shallow cone. There are specific grease gun adapters to fit those, basically the same shape but opposite.

 

But that brings up a couple good points. It’s good to make sure you orient the grease fittings in a way you can get at them. I had a one-ton on the hoist yesterday where I couldn’t grease the rearmost driveshaft ujoint because it was installed with the nipple pointed straight at the pinion yoke. If it had been flipped around and pointed facing the shaft it wouldn’t have been an issue. 
One other less critical point, it’s nice to line up all the nipples along a shaft so they’re all pointing the same direction. It doesn’t improve function at all, but it makes it quicker to find them when you’re greasing them, instead of being pointed in random directions. 

 

I'd have thought narrower heads would be commonly available, given that grease fittings can live in tight spots.  But if they exist google's not bringing them up.

 

I've seen that you can buy needle style fittings to replace the standard zerks (make sure to get the right threads I guess), then I've also read that you can use a needle style grease fitting on a zerk, but it takes some force to hold the fitting's ball valve open with the needle so the grease can make it past the fitting and into the part.

 

Good points on the fitting orientation! 

I'll keep that in mind when I put stuff together.

[Eagle_SX4]

 

1 hour ago, brucecooner said:

 

I'd have thought narrower heads would be commonly available, given that grease fittings can live in tight spots.  But if they exist google's not bringing them up.

As for grease fittings LockNLube has a bunch of different adapters for your grease gun to fit into tight spots. https://locknlube.com/collections/quick-connect-adapters

I have the push on 90 degree adapter. It can work if the grease fittings are clean but if they are plugged with old grease it doesn't work very well.

[gogmorgo]

Mm. Yeah. The 90° fitting is handy. I used to have a grease gun where I'd just added a 90° brass elbow between the hose and standard tip. It made it much easier to push and hold the tip in place on an obstinate nipple, or just made up for worn out tips that won't hold themselves nicely on the nipple. Grease guns universally use 1/8"npt fittings so it's not difficult to track down an elbow. You can really lean on that elbow instead of trying to push down on a greasy hose.
I've never really cared much for adapters that lock onto a nipple, beyond the standard ones with their little bit of grip. It adds bulk, makes it tougher to get into some spots, and makes it cost more to replace when you inevitably wear it out prematurely from hitting a bunch of rusty old nipples. When you're using them professionally, you go through them. It also adds an extra step unlocking it to move to the next nipple, which is fine if you're only doing a handful of grease fittings, but when you've got like 70 of them on a tandem plow truck with a sander body on it and you might do two trucks in an afternoon, that's a lot of extra steps.

[brucecooner]

8 hours ago, Eagle_SX4 said:

 

As for grease fittings LockNLube has a bunch of different adapters for your grease gun to fit into tight spots. https://locknlube.com/collections/quick-connect-adapters

I have the push on 90 degree adapter. It can work if the grease fittings are clean but if they are plugged with old grease it doesn't work very well.

 

I think the "recessed fitting" model is what I'm looking for.

https://locknlube.com/collections/quick-connect-adapters/products/recessed-fitting-adapter

 

My son and I got the front shaft disassembled today, but while my son was cleaning the main shaft he discovered a crack on one of the ears of the rearmost yoke.

It is a little out of round too, as if hit from the outside.  We never hit it on the outside, but I'm guessing one of the other parts of the CV joint might have banged into this.

The crack does T out, on the outside of where the snap ring recess is on the inside.

 

It's bunged up a bit inside too.

 

 

 

 

Now I'm wondering if we managed to destroyed this shaft.

 

 

 

 

[gogmorgo]

If the crack's bright and shiney inside then it's recent, if not it's probably been there for some time. The edge isn't flattened or rolled over doesn't look like it's been smacked with anything too hard, so it's possible that there was some rust or debris from the snap ring groove that got caught in between the bore and cap and pushed it apart. If it's just in the snap ring groove a little kiss from a welder might be all it needs to stop it from propagating. But if the nub that goes into the centring ball is worn down so it's loose then it might be time for a new shaft. 
But it happens. Metal parts that have been pressed together for decades don't always like coming apart like they should.
A little bit of scoring in the bore is normal. I usually like to try to clean it up with something, stiff wire brush or some emery cloth, just to get rid of any loose rust but not really to remove material. It's not a bearing or seal surface so it doesn't need to be perfect so long as it's not loose enough the cap moves around inside the bore.

Also that centring ball, I forgot to say something above. In addition to the spring it's also supposed to have needle bearings inside it, same as a ujoint cap.

[brucecooner]

Thanks for the info.

 

I'm leaning toward a new shaft, and am wondering if there's any mild upgrades I could look for while I'm at it.

 

 

I'd like to give it a little lift some day, and was considering one of these with extended splines.

https://4xshaft.com/products/xj-cherokee-front-drive-shaft

 

Very overkill for my getting around town, but I still hold out the hope I might get it off the pavement, someday.

 

[89 MJ]

8 hours ago, brucecooner said:

Very overkill for my getting around town, but I still hold out the hope I might get it off the pavement, someday.

An upgraded shaft really isn’t necessary. It seems like front axles get broken more than driveshafts, but a used shaft you buy might not be any better, so getting a new one makes sense. 
 

Nothing wrong with overkill either. I don’t like doing things twice, so I fully support putting on the best stuff you can.