Front Drive Shaft Update

[ORSO]

I removed the shaft, and fortunately, I managed to get home without any damage. After removing the teraFlex CV joint, which had been installed just 2,000 km ago, I noticed that the snap ring that holds the shaft in place had failed, causing it to pop out. The original CV joint, as already mentioned, was inserted by interference, while this replacement for the teraFlex went in very easily. This probably caused the force to be completely discharged onto the snap ring.

 

[Rayzar]

A good question. There are a couple of chaps on the local whatsapp group here that seem pretty well connected and are technically savvy but..... currently we are navigating a change in dealership in Perth and their current focus is on establishing a strong relationship with the new dealer and migrating some ongoing issues the group were tackling with Ineos/Magic. Some of the whatsapp members are on here so they may catch this, but I reckon any approach will be after the dealer transition settles.

Apparently the new agent Eurokar will be open for business in early November and its lights out for Magic on the 31 December. My annual is due mid November so hoping they will be open for business very soon.

Cheers
Steve

Went and test drove a wagon at Magic. Their yard is so small you couldn't swing a cat by its tail. Hope the next dealership is bigger.

 

[Dokatd]

I removed the shaft, and fortunately, I managed to get home without any damage. After removing the teraFlex CV joint, which had been installed just 2,000 km ago, I noticed that the snap ring that holds the shaft in place had failed, causing it to pop out. The original CV joint, as already mentioned, was inserted by interference, while this replacement for the teraFlex went in very easily. This probably caused the force to be completely discharged onto the snap ring.

I have seen stock CV's slip off and on just like the Terra joint. Mine was moderately firm. Regardless, there really shouldn't be any force on the snap ring at all.

 

[ORSO]

Since the teraflex joint fits too loosely without any friction and since the teraflex boots are compatible with the original joint, I reassembled the original joint with the two teraflex boots waiting for someone to find a definitive solution

 

[NQ94]

I removed the shaft, and fortunately, I managed to get home without any damage. After removing the teraFlex CV joint, which had been installed just 2,000 km ago, I noticed that the snap ring that holds the shaft in place had failed, causing it to pop out. The original CV joint, as already mentioned, was inserted by interference, while this replacement for the teraFlex went in very easily. This probably caused the force to be completely discharged onto the snap ring.

I can't recall if you repaired the shaft from a previous failure with the Terraflex joint and the damage was caused then but the circlip groove on spline on the shaft in the photo appears unserviceable now. There is a radius/chamfer on the face of the circlip groove the circlip has to work against. It is quite likely the circlip is going to come off again. Circlips generally have a flat side and a slightly curved side from when made, its a good idea to place the flat side against the side of the groove that will take the most load.

 

[Tazzieman]

I can't recall if you repaired the shaft from a previous failure with the Terraflex joint and the damage was caused then but the circlip groove on spline on the shaft in the photo appears unserviceable now. There is a radius/chamfer on the face of the circlip groove the circlip has to work against. It is quite likely the circlip is going to come off again. Circlips generally have a flat side and a slightly curved side from when made, its a good idea to place the flat side against the side of the groove that will take the most load.

And the splines look "unwell" to me

 

[C-Mack]

From the pictures it looks like the clip groove is chamfered or worn on both the spline side and end of the shaft side. There is going to be both push and pull tension as the driveshaft tries to slide fore and aft in the CV joint splines during axle compression and extension. Those chamfered or rounded edges are going to act like small ramps which the clip is going to ride up effectively trying to open the clip as you would do when removing the clip with c-clip pliers. Do that a few thousand times as everything moves about and it's possible to imagine the clip flexing enough to fatigue crack and split in half.

 

[Clark Kent]

From the pictures it looks like the clip groove is chamfered or worn on both the spline side and end of the shaft side. There is going to be both push and pull tension as the driveshaft tries to slide fore and aft in the CV joint splines during axle compression and extension. Those chamfered or rounded edges are going to act like small ramps which the clip is going to ride up effectively trying to open the clip as you would do when removing the clip with c-clip pliers. Do that a few thousand times as everything moves about and it's possible to imagine the clip flexing enough to fatigue crack and split in half.

I've asked before but didn't see an answer.
Has anyone checked the dimensions from the T/C flange to the differential flange when the suspension is at the limits of travel for standard and lifted and then compared that to the driveshaft length? In other words: Is the driveshaft hitting its maximum and minimum working length including slip joint travel, but working under some residual tension and compression when the suspension is fully flexed? That would be hammering the c-clip once the splines loosen up. Do that for enough cycles and we could expect to see potential failure/dislodgement of the c-clip.

Secondly: Where does the slip joint vent to? I can't see a vent in the boot so I assume it vents inside the driveshaft. Every slip joint/yoke I've played with has been free moving on the splines but any significant spline stiffness or insufficient venting would turn the slip yoke into a piston and slowly hammer out the c-clip.

All postulation folks. Jump in if you have already looked at this or have any answers.

 

[Dokatd]

Mine is pretty crisp still. The end is sharp but the spline side is chamfered.

 

[Dokatd]

I've asked before but didn't see an answer.
Has anyone checked the dimensions from the T/C flange to the differential flange when the suspension is at the limits of travel for standard and lifted and then compared that to the driveshaft length? In other words: Is the driveshaft hitting its maximum and minimum working length including slip joint travel, but working under some residual tension and compression when the suspension is fully flexed? That would be hammering the c-clip once the splines loosen up. Do that for enough cycles and we could expect to see potential failure/dislodgement of the c-clip.

Secondly: Where does the slip joint vent to? I can't see a vent in the boot so I assume it vents inside the driveshaft. Every slip joint/yoke I've played with has been free moving on the splines but any significant spline stiffness or insufficient venting would turn the slip yoke into a piston and slowly hammer out the c-clip.

All postulation folks. Jump in if you have already looked at this or have any answers.

The shaft on mine extends a couple inches beyond the length between the flanges at full extension on my two post lift.

I can't speak to the slip joint vent, but it's largely compliant. Though it does have a pretty significant spring effect due to the hard plastic boot.

 

[C-Mack]

I've asked before but didn't see an answer.
Has anyone checked the dimensions from the T/C flange to the differential flange when the suspension is at the limits of travel for standard and lifted and then compared that to the driveshaft length? In other words: Is the driveshaft hitting its maximum and minimum working length including slip joint travel, but working under some residual tension and compression when the suspension is fully flexed? That would be hammering the c-clip once the splines loosen up. Do that for enough cycles and we could expect to see potential failure/dislodgement of the c-clip.

Secondly: Where does the slip joint vent to? I can't see a vent in the boot so I assume it vents inside the driveshaft. Every slip joint/yoke I've played with has been free moving on the splines but any significant spline stiffness or insufficient venting would turn the slip yoke into a piston and slowly hammer out the c-clip.

All postulation folks. Jump in if you have already looked at this or have any answers.

Just a wild guess but I assume all that would need to happen is for the main driveshaft slip-joint to be ever so slightly stiffer to slide than the splines in the CV joint for some fore and aft load to be transferred to the c-clip in the joint. I don't even think it has to be a heavy force or end-of-travel type of an impact to make the c-clip flex in it's groove. Most likely it's just a small amount of force transferred over many cycles which makes it fatigue. Like the old paper clip example... not a lot of force required but repeated cycles of flexing over time.

Curious, for those who have replaced their joints with a TerraFlex one are the c-clips the same thickness as stock and does the c-clip take up the entire width of the groove and fit tight or is there some free-play?

 

[NQ94]

I've asked before but didn't see an answer.
Has anyone checked the dimensions from the T/C flange to the differential flange when the suspension is at the limits of travel for standard and lifted and then compared that to the driveshaft length? In other words: Is the driveshaft hitting its maximum and minimum working length including slip joint travel, but working under some residual tension and compression when the suspension is fully flexed? That would be hammering the c-clip once the splines loosen up. Do that for enough cycles and we could expect to see potential failure/dislodgement of the c-clip.

Secondly: Where does the slip joint vent to? I can't see a vent in the boot so I assume it vents inside the driveshaft. Every slip joint/yoke I've played with has been free moving on the splines but any significant spline stiffness or insufficient venting would turn the slip yoke into a piston and slowly hammer out the c-clip.

All postulation folks. Jump in if you have already looked at this or have any answers.

Beat me to it. I have had larger version of these spicer non greasable truck slip joints do the same piston thing. Pull the Uj back and it will create a vacuum then retract or pressurise and expand. Pretty sure because of being non serviceable Spicer Life series SPL slip joints are not vented. Not really an issue with bolted flanges but a real pain when trying to remove and fit them.
Would Spirolock suit this application better then a circlip

 

[Dokatd]

Just a wild guess but I assume all that would need to happen is for the main driveshaft slip-joint to be ever so slightly stiffer to slide than the splines in the CV joint for some for and aft load to be transferred to the c-clip in the joint. I don't even think it has to be a heavy force or end-of-travel type of an impact to make the c-clip flex in it's groove. Most likely it's just a small amount of force transferred over many cycles which makes it fatigue. Like the old paper clip example... not a lot of force required but repeated cycles of flexing over time.

Curious, for those who have replaced their joints with a TerraFlex one are the c-clips the same thickness as stock and does the c-clip take up the entire width of the groove and fit tight or is there some free-play?

There is no doubt, but this is a design that's been on jeeps etc for a very long time.

That said, there is a very small amount of end play with the Terra joint vs the stock. Well, I think anyway. The stock joint on average is a tighter fit so it won't move much regardless of end play. The clips themselves are identical.

I would suggest that a light peening of the splines may help the Terra joint lock in a bit.

 

[Clark Kent]

Ok, there might be a little bit in this. Thanks for your input.

• The free length on extension (droop) sounds ok according to @Dokatd. Nothing known about the minimum length in compression but the fail events posted so far have all been due to tension (pulling) against the c-clip.
• The slip joint boot is a stiff plastic and appears to resist compression, noted by @Dokatd. Further, the slip joint is semi-sealed/non-user serviceable and that has a further effect of making the shaft stiff to compress and extend according to @NQ94. This will put some axial load on the joint and c-clip with minimal effect on a new (tight) factory joint but it could start to chatter as the joint wears. Probably not healthy for a looser fitting Teraflex joint.
• The Teraflex joint might be more prone to c-clip damage.* Monitoring would require removal of the driveshaft then the end cap to inspect the c-clip and splines.
• A Spirolox spiral retaining ring as suggested by @NQ94 could provide better engagement into the spline groove. Not really an option for a factory joint with intact warranty cover but a consideration for those already running the Teraflex joint outside IA warranty. Deets.

*A tip from my helicopter maintenance days is to use an epoxy filler as a spline barrier. Coat the splines with something like Metalset Part A (only!). That acts as a gap filler to increase tension in the spline joint without affecting disassembly. The joint spline is providing drive and should have no or minimal axial movement so it doesn't need a sliding lubricant. Not to be confused with the driveshaft yoke slip joint.

Edited including corrections from @NQ94 below.

 

[NQ94]

Ok, there might be a little bit in this. Thanks for your input.

• The free length on extension (droop) sounds ok according to @Dokatd. Nothing known about the minimum length in compression but the fail events posted so far have all been due to tension (pulling) against the c-clip.
• The stiff slip joint boot acts like a spring. That can have a bellows effect according to @NQ94. This will resist slip spline movement in both directions and put some axial load on the joint. Minimal effect on a new (tightly factory joint but could start to chatter as the joint wears. Not healthy for a loose fitting Teraflex joint.
• The looser Teraflex might be more prone to c-clip damage. Monitoring would require removal of the driveshaft then the end cap to inspect the c-clip and splines.
• A Spirolox spiral retaining ring could provide better engagement into the spline groove. Not really an option for a factory joint with intact warranty cover but a consideration for those already running the Teraflex joint outside IA warranty. Deets.

Have to correct something. The bellow is not normally the issue and are quite pliable. Spicer non servicable type slip joints used on ISO drive shafts are very well sealed and the coating on the splines with the installed lubricant helps give the a good hydraulic seal that can require a decent effort to collapse or extend the joint even without the bellows. These slip joints are designed to go 500k km+ in a truck without servicing, no greasing and are sealed well to keep our contaminants.

 

[Clark Kent]

Have to correct something. The bellow is not normally the issue and are quite pliable. Spicer non servicable type slip joints used on ISO drive shafts are very well sealed and the coating on the splines with the installed lubricant helps give the a good hydraulic seal that can require a decent effort to collapse or extend the joint even without the bellows. These slip joints are designed to go 500k km+ in a truck without servicing, no greasing and are sealed well to keep our contaminants.

I have made some corrections. Thank you.