double cardon in rear

[AlaskaMatt]

Anyone run one on a 4x4? I've been fighting driveline vibes due to angles and am just about ready to go a whole new direction and get the double cardon setup.

Just to answer questions, I have been through the whole driveline. All u joints are good (new), tires are balanced, pinions bearings are solid etc.

I am going to try to pick up some shims tomorrow and try one more time to get it right (rear pinion is too high) before giving up. Shims are cheap.

[Burt4x4]

I run one, my diff is pointed right at my xfer..well minus 2deg cus I have a bit of axel wrap..self canceling hahhaa
But ya works great for me. Oh I also switched too flange mount at the xfer too

[turp mcspray]

My blazer has a 6" front, 8" rear skyjacker lift. I had a new driveshaft made with a joint on the transfercase end. Zero vibration. If you do run a joint, the other end of the shaft needs to be straight in line with the pinion. Mine is a little down (like 1 degree) so the u-joint has some movement. Is you blazer lifted, or stock height?

[AlaskaMatt]

skyjacker 2.5 lift front 4 rear (all spring). Before I pulled the shims that skyjacker has in place from the factory my pinion was straight up at my t case (they appear to be 6 degree shims). With no cardon joint you can imagine how out of phase it was. I pulled the shims and it helped a bunch but it's not gone. I still need to drop the pinion a few more degrees to equal the angle at the T case. However simply reversing the 6 degree shims would be too much.

I did pick up some smaller shims today and will give it a go. I am hoping I end up with about -1 degree total pinion angle when I am done. Right now I am sure if you subtract the t case angle from the rear pinion you would end up with a positive number. Wishing I had one of those gravity angle finders right now. But you can see it even by eye.

If it doesn't work, then cardon joint and put the original shims back in to point it at the T case once again.

[vtblazer]

Yep, from Jesse @ High Angle Drivelines.

[AlaskaMatt]

Total failure today. Installed the shims and had all sorts of new rumbles. Still had the same rumble at cruise. It kicks in at 55 and is most pronounced at light load. Yanked them back out.

Back to square one. I may pick up a gravity angle finder and try for some exact measurements but I think I had to be within 2 degrees of correct just through trial and error of some different shims.

Frustrated and thinking this really may be from somewhere else. I just cannot imagine what else to check, I've really been through everything twice.

My rear end is not great, but everything I have ever read says they don't vibrate they whine and then go bang.

[72k5mike]

I have one in the rear and it is great!

I did a 63" rear spring swap with a bit of a shackle reversal. The shackle reversal pointed my pinion up straight at the transfercase. I ended up bringing a spare front driveshaft to the d-shaft shop with my rear shaft, and they mounted the double cardon joint up to my old rear shaft.

[bigbadchev72]

Just out of curiosity what tires are you running? aggressive mud tires?

I bought a High angle driveline chasing my tail on vibes while running boggers, i never got them with my 39.5 boggers, but my 35s were horrible. Might want to check that out.

Also I do not regret buying the high angle shaft one bit, it is total beef!

[AlaskaMatt]

No boggers just BFG AT's. I am going to pull the rear shaft tonight and drive to work tomorrow in front wheel drive. That should help isolate the issue.

I did that once before but it was winter and the roads were crap, so not a very good test.

[Mike C]

I had a double cardan shaft made for the back of my Jimmy about 15 years ago. This is a good mod. My original shaft was worn out and almost too short. Actually without lifting the truck I probably would have had to replace it sooner!

Mine is a Tom Woods shaft and was about $350 with shipping at the time. When I did the SF 14 bolt swap I had to drill the perches and shift the axle back in order to not have to shorten the shaft, but that had the added benefit of centering the tires in the wheel well.

Just because all of your joints are new doesn't mean the slip joint is not worn out and that the shaft is not bent.

[kilomanjaro]

Driving in fwd may help isolate if it is the rear end making the vibration.....it may not make the vibration unless the rear end is under load though....just a thought.
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[AlaskaMatt]

Originally Posted by kilomanjaro

Driving in fwd may help isolate if it is the rear end making the vibration.....it may not make the vibration unless the rear end is under load though....just a thought.
Posted via Mobile Device

Gee thanks for being a downer John! Ha!

We can hash it out over the campfire tomorrow night.


For everyone's update. Totally smooth in FWD. There is still some things going on, but I think they have another source and are an altogether other issue.

[AlaskaMatt]

Well threw new u joints in and vibes are tamed for now. The "old" ones were new in in february when I had the new drive shaft built so whatever is tearing them up is still there, but i bought myself some time.

90% settled on doing the double cardon, just need to squirrel away the cash.

[69TowRig]

I noticed a lot of vibration in mine when I first bought it. As it turned out the u-joints were out of phase (and the joints were trashed). The driveshaft had apparently been pulled apart at some point and put back together with the u-joints out of line with each other. Once I pulled it apart and re-assembled it correctly all the driveline vibration disappeared.