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Double cardan front drive shafts

6K views 42 replies 11 participants last post by  6777 
#1 ·
Does anyone manufacturer one without a centering ball? Just looking for something low maintenance
 
#2 · (Edited)
Unless I'm mistaken (and I could be), it's not physically possible to have a DC shaft without a centering ball. The only low maintenance alternative I can think of is an rzeppa style driveshaft a-la Jeep Wrangler.

Personally I don't feel much a burn with the 2000 mile service interval on DC centering balls, but then again, I don't drive 24000 miles a year and have to grease the centering ball every month.
 
#14 ·
Your second statement is false. You use one in the rear when your suspension geometry dictates. Typically this will be around the 3" lift area. Around 3" of lift it becomes nearly impossible to maintain proper ujoint-to-ujoint driveshaft angles. The vertical separation between TC and diff will be too great and the ujoints will bind, especially when the suspension drops.
 
#13 ·
The DC shaft really only has one function:

1. Reduce the operating angle of the transfer case side U-Joint by half.
2. Reduce the operating angle of the diff side U-Joint to zero.

I don't really know if the correlation between lift height and U-joint operating angle is strictly known.

I think the easiest way to determine if you need a DC shaft is by measuring your U-joint angles :)
 
#15 ·
Nope. The Rover rear suspension uses more or less parallel flanges and DC is incorrect for that geometry. If you need more angle, than you would use a wider angle joint or DC joints on both ends of the shaft. A normal DC shaft will cause vibration.
 
#17 ·
Nope. Check out Tom Woods website, it has pictures even a Canadian can figure out. :grin
Seriously though, trying to maintain parallel flanges at 3" lift or more gets very tricky. You'll need adjustable trailing arms, and your A-arm joint is going to see a lot angle even just sitting on flat ground. Not to mention the extreme angles applied to your ujoints.
 
#16 ·
Hmm...

I disagree with you, John. A DC shaft can be used in the rear. There's absolutely no reason why it could not.

Parallel driveshaft flanges does not fix the basic problem of extreme U-Joint angles.

Parallel driveshaft flanges do not fix the vibration and durability problem inherent in running extreme U-Joint angles.
 
#19 ·
So...I hate to hammer home this point, but whether or not the flanges are parallel are irrelevant compared to the huge acceleration/deceleration forces applied to the u-joints when operated at large angles.

The point is simple: parallel drive flanges are there to cancel out the primary oscillations that occur during rotation of the driveshaft. parallel drive flanges cannot violate the laws of physics. U-joint wear and higher order mode vibrations will increase exponentially as U-joint angle increases - no matter what the flanges are doing.

That picture from tom wood's site is an oversimplification of the topic and is, generally speaking, misleading!
 
#22 · (Edited)
I think I paid about $450 for each DC shaft. Maybe $485.

That said, I highly recommend that you avoid lifting your truck at all costs. Keep the truck at stock height. Lower the truck, even.

If your droop is causing problems, put in a limit strap on the front middle of the axle. Your axle will still be able to articulate.
 
#23 ·
My truck has been lifted for about 5 years so that's not gonna a change. It also has 35s on it.

My issue is that I get a very minor off throttle vibration up front, all new bushings, shocks and coils last year. U joints last year. New axel build from swivel balls out last year.

Castor isn't corrected and about 2.5 degrees negative, hence the vibration. I'm weighing new corrected arms against a new driveshaft. Both will probably be done in the long run, kinda choosing what comes first.

Right now it's looking like I'll replace my front coils again and do arms then DC of needed after castor correction.



Edit: I do appreciate your input tho on the DC pricing
 
#25 ·
Yes, 2.5 negative castor, directly from the sheet last time I had it aligned.

The return to center is also lethargic.


The negative caster will also effect the front Ds angle as the pinion location slightly changes

I'm not getting under the truck today, on Saturday I did a clutch housing and rear main... Im still burnt out
 
#26 ·
If you have an hour to spare call GBR Bill he hasn't steered me wrong yet.
 
#28 ·
Oh good, corrected arms. Arms will either correct your pinion angle to run a DC shaft, OR correct your castor, but not both.
The front shaft on these trucks was wonky right from the factory. The driveline angles were borderline needing a DC shaft for a stock truck. Rover decided to put the Ujoints out of phase instead. So when you lift the truck the pinion rotates towards the TC, exacerbating the need for a DC shaft, but its still off. Even if you install corrected arms the front angles are stupid.
Your best bet with a lifted truck is:
1) install arms to correct for pinion angle and use a DC front shaft
2) run drilled swivel balls to correct for castor.
 
#32 · (Edited)
In the front of the truck, assuming 32.375" Radius arm length (centerline of axle to center of radius arm mount):

1" lift: ~1.77 degrees
2" lift: ~3.54 degrees
3" lift: ~5.31 degrees
4" lift: ~7.08 degrees
5" lift: ~8.9 degrees

About 1.77 degrees of caster change per inch of lift. Well, at least for lifts under 10". :grin In reality, these angle changes decrease as the lift gets closer to 32.375". Also, this assumes "stock height" has the axle center at the same height as the frame attachment for the front radius arm.

Opinion: I really don't think caster correction on a defender is "necessary" per se. I have seen people on this site insist on "caster corrected swivel balls" to the point of being verbally abusive, but that doesn't jive with vehicle dynamics. Running negative caster isn't necessarily a big problem on a vehicle, especially not a 4wd one. Toe and tire diameter can adjust things to compensate for a lot of really bad setups.
 
#33 · (Edited)
I've got a GBR front DC for def/d1/RRC sitting in a box if you want to borrow it and just experiment for a while. Just say the word. It's for an lt230 conversion for one of my classics that's on hold. I can bring it to the city when I meet up with Nick (ntan) to drop off some wheels and ironically pick up my GBR rear shaft.
 
#36 ·
OK some more questions!

I found some cheap D2 front shafts. As I understand they use 1310 ujoints and are about 24in long collapsed.

200tdi/LT77 front shafts are 26in long.


So questions are:

are the flange patterns the same on both? ( I think they are)
if not can i swap over the flanges from the end of my existing shaft? (with the U joints being the same size)


If either of these are a yes, ill buy one of the cheap shafts at the pick and pull, rebuild it and lengthen it 2 inches with DOM tubing, then balance. Will be much much cheaper then buying a new shaft outright.
 
#38 · (Edited)
OK some more questions! I found some cheap D2 front shafts. As I understand they use 1310 ujoints and are about 24in long collapsed. 200tdi/LT77 front shafts are 26in long. So questions are: are the flange patterns the same on both? ( I think they are) if not can i swap over the flanges from the end of my existing shaft? (with the U joints being the same size) If either of these are a yes, ill buy one of the cheap shafts at the pick and pull, rebuild it and lengthen it 2 inches with DOM tubing, then balance. Will be much much cheaper then buying a new shaft outright.
Not sure how much cash you're going to save going this route but you probably won't end up with a comparable component IMO. D2 shafts were built on the cheap. Ask a few LR mechanics that has worked on them over the years. They're thrown away because they are not worth rebuilding. Front shaft failure is also a dangerous thing so be careful.
 

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