well, after installing the alcans and shims to get the pinion at the same angle as the tcase output (within 1 degree anyways), when driving the highway, the vibes start at about 35mph, level off at 40 and then anything over 60, when I coast down, the vibes are really bad.

The driveshaft is a standard Ujoint DS with a slip yoke.

While the pinion and Tcase output angles match well, there's still 15 degrees of deflection on the Ujoints at ride height, and I guess that's just too much (?)

The Ujoints are brand new, and the DS is freshly retubed. It does this with either of the two driveshafts I have now.

So what next?

I can reverse the 6 degree shims and rotate the axle 12 degrees up, putting it within 2 degrees from pointing straight at the Tcase output, add a SYE, and a new slip shaft. That's a lot of $. I want to be sure it's gonna work before hand.

I'm still confused why I have so much issue now....is it just that the driveshaft angle is too steep?

Also, for anyone who's used an SYE, how did you spec your driveshaft to the shop? Is the SYE bolt pattern on the Calmini SYE the same pattern as it is on the rear pinion?

Try coasting down in neutral rather than in gear. if the vibes go away, or get significantly better, you probably just need a traction bar to limit axle wrap. Its only takes a few degrees of axle wrap to get your ujoints far enough out of alignment to create vibes.

I tried in neutral too. No difference.

I'm gettng this too with my Pathy & high angles on the U joints. I've measured out my angles at the t-case and axle and they are identical. Mine vibrates in neutral as well.

I'll be going to CVs front and rear eventually.

desert rat, you do have a one piece shaft right? 15 degrees should be in the operating limits of the joints. Are the joints in phase?

If you go with an SYE it has a 1310/1330 CV pattern drilled into it. This is not the same as the Nissan pattern in the back. You would have to run a CV shaft if you point the pinion at the case. The cheapest way to go about that is to get a JY shaft and have it retubed to your lenght, you would be surprised how expensive the spicer parts are to the d-shaft shop. I think you have a 1310 shaft now, and I would probably stick with that, the 1310CV offers more angle than the 1350CV. The 1330 is no stronger than a 1310 and seems to have the same angle as a 1350.

Im surprised how strong a 1310 is, I got my first failure on one this past week-end doing a front dig with tires bound and slap full of water, even at that it did not break the cross.

I already tried a JY shaft retubed to my length. A CV was what I was thinking about with the SYE.

That said, I'll need to tell a driveline shop I need the Nissan bolt pattern in rear. Is that at all standard, or is it unique to Nissan?

The rear flange is Spicer but I don't know the number. Just use your old one or grab one from the salvage yard to use if you need send them one for the build/balance. Would be cheaper than buying a new one from the shop. If nothing else, give them the bolt patern (measurement) and pilot size and they should be able to match it.

I know Jesse at High-Angle driveline has done several driveshafts for Nissans. High Angle Driveline

I would remove the rear axle shims cut and rotate the spring purchases. On the new spring purchases I would go with the 8" purchases that ruff stuff makes.

I looked into do the SYE, The rear output on the tranny is case hardened. I decided not to mess with the sye. Yes standard spicer parts add up. My front shaft was almost $500. Both the tranny slip yoke and axle flange are standard spicer parts.

I would hold off on the sye and cv shaft. I would cut and rotate the spring purchases and see what happens. Sye and a cv-shaft is expensive.

quote:

Originally posted by LordBiotree:
I would remove the rear axle shims cut and rotate the spring purchases. On the new spring purchases I would go with the 8" purchases that ruff stuff makes.

I looked into do the SYE, The rear output on the tranny is case hardened. I decided not to mess with the sye. Yes standard spicer parts add up. My front shaft was almost $500. Both the tranny slip yoke and axle flange are standard spicer parts.

I would hold off on the sye and cv shaft. I would cut and rotate the spring purchases and see what happens. Sye and a cv-shaft is expensive.

Bio, what benefit would I be getting from cutting and rotating the perches? The shims accomplish exactly the same thing, and the angles are right at this time. There is no difference between cutting and rotating a perch 6 degrees or using a 6 degree shim - the end result puts the pinion in exactly the same place.

I've got a used driveshaft with a 1310 CV on it that you can have DR or a new one that you can have cheap.

quote:

Originally posted by Desert Rat:
I already tried a JY shaft retubed to my length. A CV was what I was thinking about with the SYE.

That said, I'll need to tell a driveline shop I need the Nissan bolt pattern in rear. Is that at all standard, or is it unique to Nissan?

I was just saying that the shaft is alot cheaper if you have them build it from JY shafts. For instance a 1350cv is around $300 IIRC and a 1350 slip parts are another $100 or more once added up, but you can get a whole shaft for $75 and have that re-tubed you know.

The rear flange is something that your shop should have. My local shop in town had one on the shelf. You should have the 1310 joints so it wouldnt be hard to get press your old one onto the end of their shaft.

quote:

Originally posted by Desert Rat:

quote:

Originally posted by LordBiotree:
I would remove the rear axle shims cut and rotate the spring purchases. On the new spring purchases I would go with the 8" purchases that ruff stuff makes.

I looked into do the SYE, The rear output on the tranny is case hardened. I decided not to mess with the sye. Yes standard spicer parts add up. My front shaft was almost $500. Both the tranny slip yoke and axle flange are standard spicer parts.

I would hold off on the sye and cv shaft. I would cut and rotate the spring purchases and see what happens. Sye and a cv-shaft is expensive.

Bio, what benefit would I be getting from cutting and rotating the perches? The shims accomplish exactly the same thing, and the angles are right at this time. There is no difference between cutting and rotating a perch 6 degrees or using a 6 degree shim - the end result puts the pinion in exactly the same place.

He does not believe in shims.

I see....well, those shims are solid steel and are bolted to the spring pack using the center pin. The cool thing is I can just flip them around to tilt the axle up 12 degrees and be real close to pointing right at the Tcase with the pinion.

I've got an SYE lined up, and I talked to Calmini about where they had their drivelines made for the Calmini hardbody.

I think that's the ticket.

Brent, I'll let you know if I need parts.

Actually, there's a huge difference in shims vs. a cut-n-rotate. Shims change the caster, making the vehicle behave very differently, many times making it unsafe to drive, especially during emergency maneuvers like a panic stop. The effects are usually noticed first in the way the steering wheel returns to center after a turn- or doesn't. DR, I assume you aren't having issues without the driveshaft turning- if you are, it could be because your caster is way out of whack. If the problem is only while the driveshaft is turning, it is less likely to be a caster issue, although still possible because power to the front wheels might be causing the vibrations.

Whatever you find, you should know that caster will definitely affect the way it handles, so try to find a way to get rid of the vibes with the caster set as close as possible to spec. What spec? I have no idea- I'm sure IFS and solid axle trucks have different specs. If it helps, the Landcruiser solid axle spec is between 2 and 4 degrees positive. This is a major issue in the LC community, making certain size lifts very difficult to do because a particular lift height with caster corrected puts the driveshaft in an angle that can't be made smooth with either a DC (CV) driveshaft nor the standard type. 2" lifts can be made to run smooth with correct caster (bushings, similar to shims) with a stock driveshaft, 6" requires a DC driveshaft, but 4" is a crapshoot, with many people unable to make their truck handle well without vibes. A cut-n-turn is their only option, as might be yours.

In any case, I guess the only way to figure out what you need is to get rid of the vibes, then decide if you need to correct the caster with the cut-n-turn. Or, since you have part-time 4wd, you might want to make the truck drive nicely on-road and put up with the vibrations off-road. Seems odd that you'd be going fast enough in 4wd to notice them though.


-Spike

This is for a rear driveshaft, no caster.