Front drive shaft broken

[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.

 

[C-Mack]

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.

Exactly, modifications can be a slippery slope of issues at times as you discover additional modifications are required to fix the compromises of the first modifications, which lead to more and so on, etc... The more money you invest into a project can make you more reluctant to abandon previous modifications which creates a type of tunnel vision or vicious cycle until one day out of frustration you realize it has all been a bit of a let down.

Sure, I’m painting an extreme scenario above just as an example, but as most folks know, doing your homework and having a good understanding of the pros & cons you can typically avoid most of the hassle. That’s why I think this forum is so important for Grenadier owners as you can learn not only what you “can do” but equally, if not more importantly, what “not” to do at times.

 

[angstorms]

We really need this picture for Ineos axels. I know c-mack will recognize this is for Dana axel. Has anyone really measured if Pinon angle was zero what caster angles relationship really is for the Carraro axels and documented it.

This show ratio of Pinion angle vs Caster angle, this would help these discussions. since this what we moving if we adjust length of lower or upper control arms around the center of the axel. We need this for picture for the Grenadier, then it we have a key inputs for really a math problem for a four link suspension. Right now we have fixed length arm the upper, and lower is varied to increase caster angle, but when you do increase the caster angle pinion angle also changes which really what nicely people are trying to get across. You could do the same and set the bottom link to fixed length and then pull in or push out top link and it will change caster and pinion angle.

T

 

[C-Mack]

We really need this picture for Ineos axels. I know c-mack will recognize this is for Dana axel. Has anyone really measured if Pinon angle was zero what caster angles relationship really is for the Carraro axels and documented it.

View attachment 7883234

Humbly, I couldn’t tell you what sort of axle the illustration represents but thank you for sharing as it perfectly illustrates the hard fixed relationship between caster/pinion we all should be aware of. Would love to know what engineering considerations the IA/Carraro teams went through to give us the present setup on the Grenadier?

 

[Zimm]

when the rig is getting an alignment, pop off the shaft and get a reading.

 

[C-Mack]

Take some caster/pinion measurements at various axle articulation points to see how things change through the range of suspension travel. Or better still, take measurements at the simulated ride heights of the most common springs on offer such as stock, 1.2”, 1.7”, 2.5”, etc… to help give folks a heads up on the pinion/caster changes they can expect to encounter.

Surely some of the bigger/well known aftermarket shops currently doing lifts on the Grenadier could remove the front stock springs during an install on one of their product test vehicles and use a couple of tall jack-stands under the axle to positioned at the different spring heights and take some basic measurements? That would be very kind and helpful of them for the sake of public knowledge.

 

[TahoeGren]

Yeah would be great to get true measurements for all those variables with the shaft off for accuracy. I think lifting at the frame to simulate various lift heights could work too.

Looking at my notes from a while back, I measured the pinion was pointing down 2.4 degrees with caster at the nominal 2 degrees and stock springs. I used the face of the bolts as I didn’t take the driveshaft off, so not super accurate. I measured using a Klein angle gauge.

 

[Dokatd]

Best update I have at the moment is that I am in discussions with an alternate shop. Tom Woods is still on the table, but their capabilities may not meet our needs. I will update once something of consequence happens.

 

[Zimm]

Best update I have at the moment is that I am in discussions with an alternate shop. Tom Woods is still on the table, but their capabilities may not meet our needs. I will update once something of consequence happens.

boo tom woods.

 

[Dokatd]

boo tom woods.

Well, it's kind of understandable to a degree. They currently lack some of the required fixturing. I have offered to front the money to buy what's needed. Conversations are still being had.