Front drive shaft broken

[Zimm]

Those are U Joints and not CV's but many attempts have been made to develop a double cardon style driveshaft then they have been met with harmonic issues.

Yea, but that picture only applies to shafts without dc’s or cv’s, and being that we have cv’s, it doesn’t explain anything.

For anyone confused,

Just to be clear, a Ujoint, accelerates and decelerates thru its motion, and to offset that force, and prevent vibration, the joint at the other end needs to be of the same mass, angle, and 90* out of phase to offset.

A CV has a Constant Velocity, and doesn’t suffer from this.

A DC or Double cardon, has built in offsetting acceleration, so it is NoT actually a CV. It’s advantage being, it’s easier to make and easier to make durable in small diameter package. You can make a true ball and cage CV just as strong, but you may not like the size of it.

The tried and true solution for extreme angles has been to put ONE DC at the t case, and point the pinion u joint directly at the output of the DC to eliminate any angle at the pinion, and any acceleration forces… nominally. DC’s lack the machining precision of CV’s and this cut and turn system typically works for 4X4 speeds on the highway. It’s nothing you would want at 220mph. In big lifted trucks some of that vibration bubba is feeling at 90mph may not be the tire lugs alone.

The aftermarket shafts attempted were trying to eliminate the boot failure of the CVs without resetting any angles, so they eliminated the CV’s in favor of a double cardon at each end…. The effect on each other would be like squaring any small vibrations from machining imperfection each unit would have, and while admirable for the attempt, was a really tall ask. Even IF they worked out of the box, I wouldn’t think you’d be very happy with the durability. It wouldn’t take much wear at all for a tiny vibration to start and it would head downhill pretty quickly from there.

The moral of the story is… someone needs to get ahold of a wrecked unit for a front axle, and play with cutting and turning it. Ain’t gonna be me! I’ll be happy to follow once someone works it all out, though.

 

[Zimm]

I’ll add…. It isn’t that uncommon to have to work hard to properly lift a truck. The axles on my fj40 have been turned, and I limited the fj60 and Gwagon to 2” springs to avoid it. This one may be a bit more persnickety, BUT the drivetrain is already tucked high up in there, and the truck already eats 35’s (nominal) so, one could argue much of the work that ends up causing issues that require extra work with other rigs, has already been baked in here. The overall net effect making it all equal. Think about it. You need a 4” lift and pinion angle work for an fj80 to run clean on 35’s, well duhhhhh, it’s mostly done on the Gren already. It seems everyone wants to just buy 500 dollar springs and run 37’s. That ain’t happinin’.

 

[Commodore]

I’ll add…. It isn’t that uncommon to have to work hard to properly lift a truck. The axles on my fj40 have been turned, and I limited the fj60 and Gwagon to 2” springs to avoid it. This one may be a bit more persnickety, BUT the drivetrain is already tucked high up in there, and the truck already eats 35’s (nominal) so, one could argue much of the work that ends up causing issues that require extra work with other rigs, has already been baked in here. The overall net effect making it all equal. Think about it. You need a 4” lift and pinion angle work for an fj80 to run clean on 35’s, well duhhhhh, it’s mostly done on the Gren already. It seems everyone wants to just buy 500 dollar springs and run 37’s. That ain’t happinin’.

I agree with you except for the FJ80 comment. I ran 315/75r16 (34.6") tires on my 80 on stock wheels and stock suspension without rubbing. It really did crush the acceleration and needed a regear.

 

[Zimm]

I agree with you except for the FJ80 comment. I ran 315/75r16 (34.6") tires on my 80 on stock wheels and stock suspension without rubbing. It really did crush the acceleration and needed a regear.

Well, I can’t dispute your experience, but an 80 in our LC club was always 2” min with some rubbing at full stretch, and 3+ caused 3link caster issues that really needed correcting at 4. Same with any G over 2, and 2 only got ya 33’s on that one.

All I really hate on the Gren for wheeling is that frigging gas tank hanging down like a saggy nutsack waiting for that painful “grazing” off a rock tip.

 

[Tr182md]

I am surprised to hear that the coolant line was a one of. I thought part of the appeal was that the parts were borrowed from other vehicles and readily available?

 

[anand]

I am surprised to hear that the coolant line was a one of. I thought part of the appeal was that the parts were borrowed from other vehicles and readily available?

Nothing other than engine hardware and the generalities of the transmission (gearing is bespoke) are directly borrowed from anything else. They are from well known manufacturers, but not generic or borrowed parts

 

[Tinerfeño]

1. Yea, but that picture only applies to shafts without dc’s or cv’s, and being that we have cv’s, it doesn’t explain anything.

2. A DC or Double cardon, has built in offsetting acceleration, so it is NoT actually a CV. It’s advantage being, it’s easier to make and easier to make durable in small diameter package. You can make a true ball and cage CV just as strong, but you may not like the size of it.

3. The tried and true solution for extreme angles has been to put ONE DC at the t case, and point the pinion u joint directly at the output of the DC to eliminate any angle at the pinion, and any acceleration forces… nominally. DC’s lack the machining precision of CV’s and this cut and turn system typically works for 4X4 speeds on the highway. It’s nothing you would want at 220mph. In big lifted trucks some of that vibration bubba is feeling at 90mph may not be the tire lugs alone.

1. My comment was related to standard U-joint propeller shafts.

2. The uneven run of the centre part shold't be a problem. Discovery 2 has front propshaft with DC on transfer box end and pretty straight U-joint in axle end. Top speed is something like 160 km/h (100 mph) and I don't remember any problems. Some of the cars also have 50-70 mm suspension lift. I also have modified two cars for standard Disco 1 front propshaft. No probems in our legal speeds (up to 120 km/h). This could be fauirly easy to test and see if that is applicable. At least for regular speeds up to 100-120 km/h.

3. The prposed orientation is perfect. But what is "DC’s lack the machining precision"?

 

[NQ94]

There is a few photos and considerable discussion on "Ineos Grenadier Owner's Club "FB page showing a double cardan failure in the front axle. The failure cause looks more like the result of how the vehicle was operated. From the OPs photos the axle is around 35.15mm diameter.

 

[Commodore]

There is a few photos and considerable discussion on "Ineos Grenadier Owner's Club "FB page showing a double cardan failure in the front axle. The failure cause looks more like the result of how the vehicle was operated. From the OPs photos the axle is around 35.15mm diameter.
View attachment 7889038

Front axle and front driveshaft are very different. That said, I saw that post on Facebook and don't entirely believe that it is legitimate.

 

[TCMColorado]

There is a few photos and considerable discussion on "Ineos Grenadier Owner's Club "FB page showing a double cardan failure in the front axle. The failure cause looks more like the result of how the vehicle was operated. From the OPs photos the axle is around 35.15mm diameter.
View attachment 7889038

Quite likely a result of having the front axle locked, a high degree of steering angle and too much throttle. In other words driver error.

 

[Dokatd]

In my book that's more of a U-joint failure not a failure of the DC portion so to speak.

Regardless, are there any other pics? Maybe some showing the outer knuckle too? Hoping to confirm a few things.

 

[AWo]

Yea, but that picture only applies to shafts without dc’s or cv’s, and being that we have cv’s, it doesn’t explain anything.

For anyone confused,

Just to be clear, a Ujoint, accelerates and decelerates thru its motion, and to offset that force, and prevent vibration, the joint at the other end needs to be of the same mass, angle, and 90* out of phase to offset.

May I add....the 90 degrees only apply when the joints flex on the same plane. If they do not flex on the same plane, there must be an offset angle. That means the joints are still in phase, but not rotated at 90 degrees just at some some other angle (in fact "in phase" means: the driving yoke of the U-Joint which provides power is rotated 90 degrees to the driving yoke of the second U-Joint at the end of the shaft which delivers power to the driven yoke of the differential. So it is vice versa to the terminology @Zimm used) You see that most of the time at the front shaft and there is a reason for that.

In phase, the power delivery side (the driving yoke on the right) is rotated 90 degrees to the driving yoke on the left at the end of the shaft):

Still in phase, but with an offset angle due to the U-Joints flexing on different planes (90 degree rotation: dotted line, actual rotation: solid line).



If you look at modern 4x4 cars more closely you see that the engine and gearbox ar not leveld but the gearbox is pointing slightly down at the rear while pointing up at the front. That is because the rear prop shaft is longer and has more mass and tends more to swing. The goal is to keep this long shaft as quite an smooth as possible and thats why they try to get a straight line between the gearbox output shaft and the rear differential. Especially with non-permanent 4x4s as the rear shaft is always transfering power. Just think about Pick-Up trucks.

Remember, that the U-Joint pairs eliminate the oscillation of the U-Joint turns out, but only at both ends of the shaft. The shaft is still oscillilating and therefore its mass must be accelerated and deccelerated 4 times for each turn. That eats up power and leads to swing and vibration. BTW, a double U-Joint is nothing else than a very short drive shaft.

The disadvantage of the front outputshaft pointing up is, that it is increasing the U-Joint angle. In addition, especially when the differential is located in the middle of the axle you have an offset. That leads to the U-Joints not flexing on the same level so an offset angle must be calculated in the U-Joint phase.

There are many examples in the market. I know it from some Ford trucks, the Range Rover Classic and P38 and the Defender Td4 110.
Example of driveshafts from a Land Rover 101 Forward Control (front shaft, in phase with an offset angle) an a 90ty Defender Td5 (rear shaft, in phase without an offset angle):



You can read my article on this. There are some pictures explaining the level thing (and you can see my 90ty from below ;-) :

Alles über Kardangelenke

Überall dort wo es gilt eine Drehung um einen Winkel herum zu übertragen kommen zwei Arten spezieller Gelenke zum Einsatz. Entweder es ist ein Kardangelenk oder ein Homokinet. In diesem Artikel geht es um das Kardangelenk, seine Eigenschaften und den wesentlichen Unterschied zum Homokineten.

matsch--und--piste-de.translate.goog

Hopefully Google got the translation right.

AWo

 

[Zimm]

I wonder if the stops were cranked all the way in.

 

[Tenac]

Quite likely a result of having the front axle locked, a high degree of steering angle and too much throttle. In other words driver error.

I didn't know that would or could be an issue. Learned something new today and note taken.

 

[Jah]

Has anyone looked into or considered cut and turn to adjust both the pinion angle and caster?

 

[Commodore]

Has anyone looked into or considered cut and turn to adjust both the pinion angle and caster?

A bunch of us are waiting for someone else to go first I have even suggested that a Grenadier specialist offer a front axle exchange.