Front drive shaft broken

[Clark Kent]

There are ~ 2500 Grenadiers in AU, and so far the reported number (on this forum and social media) that I have seen has been 3. One with lift above 40mm.

My front shaft was recently replaced because CV lube was leaking through a flange bolt hole at the transfer case end. So a shaft fault but not a boot failure. I posted about it here.
Stock suspension.

 

[Tenac]

I need some education here: I'm aligned with all the information on this thread with drive shaft breaking and by lifting putting more stress on that part as well. Would adjustable track bars help avoid the situation of lifting causing a more extreme angle??? I was watching the video below and the gentlemen states that adding the adjustment allows you to get closer to factory with the suspension??? If so this would mean I could life that 1.5" and buy the metalcloak kit to help avoid breaking with a lift.

View: https://youtu.be/ev_JUUC9q-w?t=180

 

[Walter]

I need some education here: I'm aligned with all the information on this thread with drive shaft breaking and by lifting putting more stress on that part as well. Would adjustable track bars help avoid the situation of lifting causing a more extreme angle??? I was watching the video below and the gentlemen states that adding the adjustment allows you to get closer to factory with the suspension??? If so this would mean I could life that 1.5" and buy the metalcloak kit to help avoid breaking with a lift.

View: https://youtu.be/ev_JUUC9q-w?t=180

He had a custom-made double-joint drive shaft installed.

 

[Tenac]

He had a custom-made double-joint drive shaft installed.

Yeah I seen that as well but with the custom drive shaft or shafts with these links we should have zero issues when lifting right? That's my real question here is how to avoid the risk of lifting without going portals which who knows when they will come out. It also seems like these links might help the OEM truck anyway by adding adjustments etc. ?

 

[Dokatd]

You cannot have factory caster and pinion angles with a lift. Certainly not at the same time anyways. To resolve the pinion angle issue you need to adjust the cam bolts on your lower links. When you do this you are also changing your caster. Unfortunately you are changing your caster in the wrong direction for ideal steering characteristics. Additionally you are affecting the oiling of your pinion bearings (though I am not convinced we are even close to this point).

So, the Metalcloak arms are effectively useless as you can't utilize any more adjustment than the factory arms allow for. That is assuming your trucks frame is within the average for frame dimensions. It is possible your frame was pushing the envelope for it's original dimensions and the factory cam bolts don't all enough adjustment, but I'd put money on it that this is not the case with any IG.

The Metalcloak stuff is fine if you want some bling or feel the tubular arms are necessary for strength concerns, but they are not a solution for the front drive shaft issue.

You can absolutely sacrifice your steering a bit for drive shaft angles though. And being completely honest I am currently feeling that this is more viable than we thought. But....I'm not sure it doesn't require the use of the Terraflex joints. I have a suspicion that the Terraflex joints have a different rubber compound for the boot. I'm questioning if the IG boots are failing simply due to a lower quality boot. The way the boot on mine failed made it look like the boot was 20yrs old. It felt dry and hard.

 

[C-Mack]

For sure high CV-joint angles are a contributing factor but so is the constant flexing of the stock boot as the rubber goes from stretched to compressed back to stretched once each rotation which can cause heat fatigue/hardening and tearing of the boot material.

Also, the boot cover acts as a collection point for mud/sand and all sorts of other trail debris which can cause abrasion to the boots while running. In other words, there could be several different variables all contributing at once to the driveshaft failures mentioned around this forum, but one thing is for sure, once the boot is compromised it’s joint is going to fail in short order.

 

[Zimm]

You cannot have factory caster and pinion angles with a lift. Certainly not at the same time anyways. To resolve the pinion angle issue you need to adjust the cam bolts on your lower links. When you do this you are also changing your caster. Unfortunately you are changing your caster in the wrong direction for ideal steering characteristics. Additionally you are affecting the oiling of your pinion bearings (though I am not convinced we are even close to this point).

So, the Metalcloak arms are effectively useless as you can't utilize any more adjustment than the factory arms allow for. That is assuming your trucks frame is within the average for frame dimensions. It is possible your frame was pushing the envelope for it's original dimensions and the factory cam bolts don't all enough adjustment, but I'd put money on it that this is not the case with any IG.

The Metalcloak stuff is fine if you want some bling or feel the tubular arms are necessary for strength concerns, but they are not a solution for the front drive shaft issue.

You can absolutely sacrifice your steering a bit for drive shaft angles though. And being completely honest I am currently feeling that this is more viable than we thought. But....I'm not sure it doesn't require the use of the Terraflex joints. I have a suspicion that the Terraflex joints have a different rubber compound for the boot. I'm questioning if the IG boots are failing simply due to a lower quality boot. The way the boot on mine failed made it look like the boot was 20yrs old. It felt dry and hard.

Heres a thought. It appears if one doesnt want to lift the truck the upper arms will permit dialing in a couple more degrees of camber and put the pinion side boot at about the same angle as if there was a lift, and it wont screw with the steering linkage. It would have been nice if the upper arm length and angle was designed to tilt the pinion upwards a tad under full droop, but it doesn't look that way. Skinny 35's, no lift, and some return to center sounds like a win.

 

[Dokatd]

Heres a thought. It appears if one doesnt want to lift the truck the upper arms will permit dialing in a couple more degrees of camber and put the pinion side boot at about the same angle as if there was a lift, and it wont screw with the steering linkage. It would have been nice if the upper arm length and angle was designed to tilt the pinion upwards a tad under full droop, but it doesn't look that way. Skinny 35's, no lift, and some return to center sounds like a win.

Sure, but why not run more conservative stock settings on the caster and pinion angle and just change the steering stabilizer. I'd much more prefer to swap a passive part like a steering stabilizer than a suspension link that holds the axle in place. You will get all the return to center you could ever want.

Don't get me wrong, I have made many link arms in my life and all were huge improvements, but to be fair that was to add substantial length to the arms by changing the frame side mount.

I'm not afraid to change parts, but someone worried about it should be more comfortable changing the stabilizer than putting in some new link arms. I'm not a Jeep guy so I don't know Metalcloak from Adam so I can't comment on their engineering capabilities, but I think their link kit is a bit of a fallacy.

All just my 2¢

 

[Dokatd]

On another note, I am considering reducing my caster bit by bit until I hit the stock min or find a handling issue.

I originally had my caster set with stock springs. But once the truck was lifted that caster would have changed a fair bit. I suspect I could achieve more favorable driveshaft angles if I dialed it back some. The truck handles very well as is.

 

[Tazzieman]

I'm questioning if the IG boots are failing simply due to a lower quality boot. The way the boot on mine failed made it look like the boot was 20yrs old. It felt dry and hard.

That was my thought from the outset.
It feels more like plastic than rubber, and I guess it is an amalgam of chemicals , some of which are made from Ineos petrochemicals!
I drop under the chassis after every offroad venture to check it.

 

[GN4HIR]

30min call with Tom Woods today. Things are moving along at this point. They have agreed that this is something they want to address for us. I am helping to push it along as best I can with designing and motivation.

Just thought I would ask if there has been any further progress on the Tom Woods driveshaft.

 

[Dokatd]

Just thought I would ask if there has been any further progress on the Tom Woods driveshaft.

No, with the holidays things have been slow. I will hopefully be getting some kind of update shortly after the New Year.

 

[AWo]

A double/double cardan shaft is very likely stronger, but even with good operating angles (which may not be possible on the Grenadier) they never run as smoothly as a true rzeppa style CV shaft. I have first hand experience as my Jeep Wrangler has a double cardan shaft front and rear and at certain speeds it has proven impossible to completely eliminate harmonic vibrations. Most Jeep owners accept this as a fair trade off given the technical capability on tap. But the Grenadier is much more refined both on and off road and few owers are likely to find the vibrations tolerable.

That depends on the type of double U-Joint. There are three. In cars (steering and drive shaft) you almost often find the type with external centering and they are not 100% of a CV type. Double U-Joints with an internal centering and guide are. That is due to the fact that the difference between the single bend angles of the first and second joint increases with the overall bend angle. The shaft in the axle has to be able to slide sideways due to that, to keep the difference low, but the difference exists. This leads to an unequal rotation speed of the input and output sides. If you find a Double U-Joint which is not 100% in phase, some had some thoughts about that effect and tried to further compensate it.

BTW, as a Double U-Joint brings in and eliminates its own rotation error, it can't be used to eliminate the rotation errors of other U-Joints. It is therefore used to allow high angles, especially at front exles. But, as the Wrangler has a four link front and rear, I would use wide angle U-Joints, as when you replace the upper U-Joint with a Double-U-Joint, you bring in a rotation error again (unequal amount of U-Joints)!
Double-U-Joints should be used where no four-link is present, as there the input and output shaft angles are not kept in a constant relation like with four-links-suspensions.

AWo

 

[angstorms]

Remember Metalcloak control arms allows you to adjust the upper and lower arms ( not just lower like we have with factory solution ), aka you have more ability to adjust geometry of the system more then just adjusting lower arms. You could shorten the upper arms and lengthen out the lower arm to rotate the axels which will change the pinion angle. Also if you put rear arm again upper and lower arm you have similar adjustments.

But I will caveat this really need to be professionally aligned at reputable 4x4 shop if you go this way. Also there is lot of set up going down this path. Also not every one needs level of adjustment.

Metal Cloak is a solid company that does quality engineering and stands behind there products, they also have help move the community from RTI to Corner Travel Index to see what suspension really doing in Jeep community, they roll out trailer that safely flexes your vehicle and also help find binding issues at all the major jeep events. For example if Rival had used this they would have known they issue with their front skid plate design hitting front axels.


Rear upper arms

Rear Lower arms

Front upper control arms

Front Lower Arms

 

[Dokatd]

Remember Metalcloak control arms allows you to adjust the upper and lower arms ( not just lower like we have with factory solution ), aka you have more ability to adjust geometry of the system more then just adjusting lower arms. You could shorten the upper arms and lengthen out the lower arm to rotate the axels which will change the pinion angle. Also if you put rear arm again upper and lower arm you have similar adjustments.

But I will caveat this really need to be professionally aligned at reputable 4x4 shop if you go this way. Also there is lot of set up going down this path. Also not every one needs level of adjustment.

Metal Cloak is a solid company that does quality engineering and stands behind there products, they also have help move the community from RTI to Corner Travel Index to see what suspension really doing in Jeep community, they roll out trailer that safely flexes your vehicle and also help find binding issues at all the major jeep events. For example if Rival had used this they would have known they issue with their front skid plate design hitting front axels.


Rear upper arms

View attachment 7883114

Rear Lower arms
View attachment 7883120

Front upper control arms
View attachment 7883115

Front Lower Arms
View attachment 7883119

Yeah, you are negating the actual problem. It's the pinion angle relative to the caster that's an issue. You cannot fix one without mucking up the other. Doesn't matter how many arms you have.

RTI ramps are fun and all but often times people focus on designing to get the highest RTI score and end up with a horrible truck in the rocks or otherwise.

Jeep owners got lucky with how the front axle was built on their trucks. As well they are not full time 4wd. Us IG guys got shafted a bit by Magna. (See what I did there).

 

[Zimm]

Yeah, you are negating the actual problem. It's the pinion angle relative to the caster that's an issue. You cannot fix one without mucking up the other. Doesn't matter how many arms you have.

RTI ramps are fun and all but often times people focus on designing to get the highest RTI score and end up with a horrible truck in the rocks or otherwise.

Jeep owners got lucky with how the front axle was built on their trucks. As well they are not full time 4wd. Us IG guys got shafted a bit by Magna. (See what I did there).

In other words… which dihard wheeler is going to trailblaze the cut and turn..

I also think there’s a bit too much worry over the pinion oiling for a couple degrees. The ring gear ought to be dousing the pinion rather heavy at speed. That’s why the rear cover is shaped like it is, to make a channel so the fluid circulates better.

 

[C-Mack]

For a while now it seems on this thread people end up talking past each other with regard to adjustable arms, pinion angles, caster etc…. @Dokatd is right though, there is no adjustment between caster and pinion angle it is a solid fixed relationship between the two because the axle is one large casting.

Just imagine the Grenadier’s axle sitting all by itself on a perfectly flat level surface. Now adjust the steering axis so it has the factory nominal 2 degrees of positive caster. Now look a the pinion… whatever angle it is sitting at is all you are ever going to have there is no possible correction between the two they are not independently adjustable from each other. In other words, there is only one possible resting position the axle can sit in relative to the road where caster is correct and the pinion angle is just along for the ride at that point.

Now imagine the axle re-attached to the Grenadier with a suspension lift. The axle is going to be sitting out of position relative to the nominal position stated above both left to right, fore and aft, in addition to pitched forward or backward depending. In other words, everything is going to be way out of position relative to the nominal stock specifications so now what do we do?

Well, if aftermarket adjustable arms are engineered correctly they should offer you enough fidelity in each axis so you can return the axle to its nominal stock geometry. I’m not even going to get into how the new adjustable arms various lengths and pivot point designs will impact what arcs the axles will move through during the entire range of travel, but it would be safe to say it will be much different to stock and introduce new overall handling characteristics to the vehicle which never seems to get mentioned.

Are big shiny adjustable arms bad, I don’t think so, and they can offer increased strength and durability if climbing rock faces is your thing. But what adjustable arms won’t do is somehow magically bend the axle housing so all of a sudden you can independently set your pinion angle relative to caster and solve steering and driveshaft issues at the same time. If you want caster and pinion issues solved at the same time that’s only going to happen with a redesigned front axle.

 

[angstorms]

For a while now it seems on this thread people end up talking past each other with regard to adjustable arms, pinion angles, caster etc…. @Dokatd is right though, there is no adjustment between caster and pinion angle it is a solid fixed relationship between the two because the axle is one large casting.

Just imagine the Grenadier’s axle sitting all by itself on a perfectly flat level surface. Now adjust the steering axis so it has the factory nominal 2 degrees of positive caster. Now look a the pinion… whatever angle it is sitting at is all you are ever going to have there is no possible correction between the two they are not independently adjustable from each other. In other words, there is only one possible resting position the axle can sit in relative to the road where caster is correct and the pinion angle is just along for the ride at that point.

Now imagine the axle re-attached to the Grenadier with a suspension lift. The axle is going to be sitting out of position relative to the nominal position stated above both left to right, fore and aft, in addition to pitched forward or backward depending. In other words, everything is going to be way out of position relative to the nominal stock specifications so now what do we do?

Well, if aftermarket adjustable arms are engineered correctly they should offer you enough fidelity in each axis so you can return the axle to its nominal stock geometry. I’m not even going to get into how the new adjustable arms various lengths and pivot point designs will impact what arcs the axles will move through during the entire range of travel, but it would be safe to say it will be much different to stock and introduce new overall handling characteristics to the vehicle which never seems to get mentioned.

Are big shiny adjustable arms bad, I don’t think so, and they can offer increased strength and durability if climbing rock faces is your thing. But what adjustable arms won’t do is somehow magically bend the axle housing so all of a sudden you can independently set your pinion angle relative to caster and solve steering and driveshaft issues at the same time. If you want caster and pinion issues solved at the same time that’s only going to happen with a redesigned front a

Wow, I was just stating there is adjustment in these control arms, but it not excessive from stock , also never said this would fix perceived steering issues, or fix Rzpenza CV issue when it bind, they are independent issues. I already read you would cut the knuckle and move them for pinion angle a while back.

 

[C-Mack]

Wow, I was just stating there is adjustment in these control arms, but it not excessive from stock , also never said this would fix perceived steering issues, or fix Rzpenza CV issue when it bind, they are independent issues. I already read you would cut the knuckle and move them for pinion angle a while back.

No worries, nobody is a supreme expert on this topic and neither am I. My main concern is often times in the auto aftermarket (of which I’ve worked) big complicated components can take on a type of panacea effect for problems people may have with their vehicles.

There are a lot of well intentioned folks who rush to modify their vehicles with the hope everything they bolt on is only going to be an improvement. In many cases they are be but I know from my own automotive failures it pays to understand the fundamentals as best you can so the optimal choices can be made so performance, reliability and more importantly safety is not compromised.

I think we’ve all experienced situations on past automotive projects where we modified our vehicles expecting one outcome but ended up with another costing both time, money and frustration. It is entirely possible to have a well sorted custom suspension setup but it takes a lot of work, research and testing to make sure it is correct.

 

[angstorms]

No worries, nobody is a supreme expert on this topic and neither am I. My main concern is often times in the auto aftermarket (of which I’ve worked) big complicated components can take on a type of panacea effect for problems people may have with their vehicles.

There are a lot of well intentioned folks who rush to modify their vehicles with the hope everything they bolt on is only going to be an improvement. In many cases they are be but I know from my own automotive failures it pays to understand the fundamentals as best you can so the optimal choices can be made so performance, reliability and more importantly safety is not compromised.

I think we’ve all experienced situations on past automotive projects where we modified our vehicles expecting one outcome but ended up with another costing both time, money and frustration. It is entirely possible to have a well sorted custom suspension setup but it takes a lot of work, research and testing to make sure it is correct.

Thanks, Completely understand, best example was every one racing out put new taller springs on the truck to put bigger tire on before the rest it was fully test and hashed changes need to make it work correctly long term.