[rs182]

Here's the report guys. Vibration between 25-35 mph is pretty bad, it resonates through the entire vehicle. I'm not sure if its the pinion angle or the stick-out of the T-case yoke or both. I'm pretty sure I'm going to have to cut off the perches and weld a new pair on to fix the vibration. Since the pinion joint is so strange I'm having a hard time finding information about it. Take a look at the pics and tell me what you think. Other than that it was a successful project. Will take some articulation pics tomorrow, I have to measure for my new shock anyway.

Pinion angle:

T-case yoke stick-out sitting level:

T-case yoke stick-out suspension fully extended:

 

[OregonX]

Wow... the amount of slip yoke exposed is scary. Remember, it's only 8.5 inches from the center of the u-joint to the end of slip yoke, and I bet you're darn close to that at full suspension droop.

My guess is that you're putting too much of an angle on that u-joint at the T/C end, but I wouldn't know for sure. If that is the case, the quickest would probably be to do what JE Reel did for Calmini on a customer rig that was having some serious vibration issues with one of their 5" kits.

They put in a CV joint (double cardan u-joint setup, not really a true constant velocity joint) at the T/C end, which also adds some length to the driveshaft and pushes the slip yoke back in some. JE Reel left the rzeppa style joint at the differential end. Maybe something to talk to your local driveshaft shop about if you don't want to ship it off anywhere.

Thanks for starting a new thread in the Projects forum, where it should be. Would still like to see some daylight pics of this thing sitting on all 4 tires.

Nice work, by the way.

 

[xterrock]

I've been following this project as it's something I really want to do. Hopefully you can resolve the problem. One question, I noticed your pinion is lined up pretty straight. The stock set-up has more of an angle, could this be one source of the vibration? I don't think that made any sense.

Is the stock driveshaft sufficient or is it being extended out to its limits on length?

Looks great!!

 

[PonyBoy]

I can't tell, but did you already weld new perches on there? Or is that the stock location? If thats the stock location, you have to have shims or relocate the perches. I would like to see what your ride height looks like too if you have a chance. Is your rake pretty bad atm?

EDIT: But yeah, from the pictures your pinion angle looks pretty good.

 

[xterera]

I agree with OregonX with it being your xfer case ujoint angles. Im guessing no one makes a fixed output yoke for our xfer case yet. Side question, is the output on the xfer case sealed internally or is it by that rubber dealie around the slip yoke.

 

[rs182]

I can't tell, but did you already weld new perches on there? Or is that the stock location? If thats the stock location, you have to have shims or relocate the perches. I would like to see what your ride height looks like too if you have a chance. Is your rake pretty bad atm?

EDIT: But yeah, from the pictures your pinion angle looks pretty good.

Yes the perches are welded on and yes the rake looks a little ridiculous now! I will post pics today. Thanks for the advice on the double CV joint for the T-case output, I have done some reading about that. I will go to a local drivetrain shop ASAP to discuss this issue. Will probably be ordering my shocks tonight too.
With the pinion being about neutral with the driveshaft, it is set up perfect to accommodate a double CV at the T-case.
So the T-case yoke is 8.5" long? I don't plan on doing any wheeling until after my driveline issues are resolved anyway.
Not sure if the T-case is internally sealed or not.

 

[OregonX]

Since your pinion angle appears to be dialed in, I would even talk to the driveshaft shop about putting in a single u-joint in place of the rzeppa. The u-joint would be stronger, and fixeable on the trail if it went out and you carry spares.

Anybody have the link for that driveshaft that Tom Woods built for somebody on here? I'm too lazy to search...

 

[Nissan AZ]

FWIW, Tom Woods built us a double cardan set-up for the RR propshaft on Project X after we installed the Atlas T/Case. Tom's got the flanges in stock for mating up with the RR axle, and based on what he's told us, he could come up with something pretty easily on the t-case side for stock vehicles as well. If you guys want, I'll try to get some pics of the truck to show what he built up for us.

~ Jason

 

[rs182]

FWIW, Tom Woods built us a double cardan set-up for the RR propshaft on Project X after we installed the Atlas T/Case. Tom's got the flanges in stock for mating up with the RR axle, and based on what he's told us, he could come up with something pretty easily on the t-case side for stock vehicles as well. If you guys want, I'll try to get some pics of the truck to show what he built up for us.

~ Jason

If you don't mind Jason that would be extremely helpful. And good idea OregonX, I'll speak to them about that as well. I'm feeling better about things now that I don't have to reweld those damn perches, that would've really sucked.

 

[OregonX]

Tom's got the flanges in stock for mating up with the RR axle, and based on what he's told us, he could come up with something pretty easily on the t-case side for stock vehicles as well.

When you say "something pretty easily on the t-case side," do you mean they've duplicated the slip yoke (which Spicer won't release as a part) or are you referring to some sort of fixed yoke (slip yoke eliminator) kit?

I might have to call them to find out. Any pics you could post would be awesome, Jason. Thanks.

 

[Gerdo]

I once read that the angle of the driveshaft and the pinion AND the angle of the driveshaft and the TC shaft should be close to the same angles. This will cancel out the vibration.

 

[IZVERG]

Apologies if I read over this, but what's the advantage of running this type setup?

 

[Muzikman]

I once read that the angle of the driveshaft and the pinion AND the angle of the driveshaft and the TC shaft should be close to the same angles. This will cancel out the vibration.

With traditional u-joints, that is true.

 

[Muzikman]

Apologies if I read over this, but what's the advantage of running this type setup?

Cheap way to lift a leaf sprung axle quite a bit (my guess he got 5+ inches of lift in the rear now).

 

[PonyBoy]

Apologies if I read over this, but what's the advantage of running this type setup?

Cheap way to lift a leaf sprung axle quite a bit (my guess he got 5+ inches of lift in the rear now).

Very true, and to add:

It keeps from having to arch the leaf springs more to add lift. This allows for flexier flater springs while also lifting the truck.

Added much needed ground clearance from the axle tube (does not affect minimum ground clearance). In other words, he does not have to worry about getting his leaf springs caught up on obstacles such as rocks etc.

 

[KillJoy]

So what happens to the front end? Larger shocks and springs?

 

[Mark]

Im thinking the front end is going to have to be the calmini or fabtech 6 inch lift.

 

[rs182]

Apologies if I read over this, but what's the advantage of running this type setup?

Cheap way to lift a leaf sprung axle quite a bit (my guess he got 5+ inches of lift in the rear now).

Very true, and to add:

It keeps from having to arch the leaf springs more to add lift. This allows for flexier flater springs while also lifting the truck.

Added much needed ground clearance from the axle tube (does not affect minimum ground clearance). In other words, he does not have to worry about getting his leaf springs caught up on obstacles such as rocks etc.

Exactly. And for the front suspension, I'm working on a custom setup for that as well, none of that ground-clearance-reducing drop bracket stuff either. Hopefully I'll be able to snap some flex pics for you guys soon, I've been really busy getting ready to travel to Africa this Christmas.
Jason, let me know about the driveline as soon as convenient.
And Gerdo, a neutral pinion-driveshaft angle is required for a double CV on the T-case side, you are right about the pinion & T-case angle if using traditional U-joints though.

 

[Nissan AZ]

Will do. I'm out of the office for the next few days, but will snap a quick photo of the underside once I'm back in the office (probably Monday).

~ Jason

 

[rs182]

Here are the pics you guys have been waiting for. Did some measuring for my shocks. The 12" 5150's will fit perfectly. Please excuse my ghetto ramp, it actually wasn't high enough. I tried to get it four tires high but it just wouldn't have it. I exploded my poor ramp in the end.

Rear tires stuff PERFECTLY now, theres seems to even be room for a little larger tire in the future...

Brake lines are plenty long enough. May have to get Revolvers just to make the extra length worth while.

Trying to determine how much I'm going to need extend my bumpstops. Gonna have to weld a plate onto the spring pads for the bumpstops to strike.

And the shot everyones been wanting to see, here she is sitting level. Well, not so level...lol. Gotta get that front in the air now!

Everything is going on hold until I get my new driveshaft, that is top priority right now. Well, I may still get my shocks.