Topic: Rear Cv drive line help.

[heep70]

I have recently installed a rear CV drive line in my Toyota. I have read a few tech articles and they all seem to bounce around the issue of setting up the pinion to driveshaft angles. I know how to set up non-CV driveline angle, but the CV stuff I am new to. Knowing that there is no real concrete answer because every rig different.

So my question is: Do I set the rear pinion inline (0*) with the driveline (ujoint end) while the truck is static (stationary). Or do I need to figure out what the degree of axle wrap is while in motion, then set the angle of the pinion short at static so that while in motion it will then change to 0*? Get it  

What I have now is a 43" rear CV driveshaft.
T-case drops 2.5*.
Driveline tilts up at 16.5*.
Rear pinion points up 15*.
That leaves me with 1.5* difference from being dead nuts on at static.

I need to get the rear u-joint at 0*. Just not sure if it needs to be done in motion or static.

So, what do you know?

[Marlin]

We prefer to angle the pinion slightly downward however, aiming the pinion straight at the rear of the t-case is also acceptable.
With a c/v joint at the t-case, there should be no angle at the rear diff.

Marlin

[heep70 [OP]]

OK, I have set the rear driveline directly inline with the rear driveshaft.  It has liminated almost everybit of the vibe.  I might try to set the rear pinion a .5* to see what that does.   

[Willy Mammoth]

The reason for a slight downward angle is so when the springs wrap up it won't go past center and cause an angle problem.

Earthier straight in line with the shaft or with a slight downward angle is acceptable.

[johnnygalt]

How do you know when you've got the pinion pointed exactly at the xfer case output flange?  Precision eyeball technique?  I use an angle finder to set the flanges parallel, but now goiong to a cv I'm a bit stumped?

[heep70 [OP]]

Just put your pinion a couple degress below the driveline angle. 

[Saber]

How do you know when you've got the pinion pointed exactly at the xfer case output flange?  Precision eyeball technique?  I use an angle finder to set the flanges parallel, but now goiong to a cv I'm a bit stumped?

Although I've always trusted my eyes to "eyeball" things, I used a laser level when I rotated my rear axle.  Below are a couple of shots.  I opted to point the rear pinion directly at the tcase and things have been super smooth ever since.  Marlin originally pointed me in the right direction on this and also mentioned to re-torque your pinion nut.  His ESP was right on, as mine was a bit loose...  Scary.  Anyway, take a look at the pics below to get an idea.  Keep in mind the 90 deg laser is directly centered on the pinion nut.  The first picture is somewhat misleading and makes it appear the laser is at the top; it is not.  Enjoy!

http://www.bikelikehell.com/tmp/Axle_Rotation_14.jpg

http://www.bikelikehell.com/tmp/Axle_Rotation_15.jpg

[johnnygalt]

Wow, now that is a great idea! I know I can wander around Home Depot until I find a laser that works, but what brand and model did you use?

[Saber]

Wow, now that is a great idea! I know I can wander around Home Depot until I find a laser that works, but what brand and model did you use?

The one I have is made by RoboToolz and actually has 3 lasers to allow for a for a perfect square.  Overkill for this application and kinda pricey.  Home Depot sells these, but I'm sure you can find a much more suitable laser.  All you really need is something that is flat and shoots a laser 90 deg out the top.

Here's the one I used:

http://www.robotoolz.com/RT-3610-3/RT-3610-3.html

This one is nice, being that it has earth magnets built in the bottom, so it sticks nicely to the flange while you make your adjustments to your spring perches and axle.  The pinion flange is nice and flat, so you'll be right on the money.  If you live in CO, swing by and you can borrow mine.

[heep70 [OP]]

Saber, what is the angle your CV is at (From driveline to t-case flange)? 

[Saber]

Saber, what is the angle your CV is at (From driveline to t-case flange)? 

Damn, sorry for the delay.  My wife hurt her back, so I've been taking care of two chicks for the last couple days (chasing our kid everywhere!).

I went out and measured my drive line angle, as I thought that might give the best results.  It appears there is a 12 deg angle, then the CV joint absorbs the rest.

Here's what I have, to help you compare your setup to maybe find a common denominator.

Rear:
5" Alcan Springs in the rear (no sag at all, so it maintained it's height)
Rear shackles are 5" eye-to-eye
Rotated axle (that pig is pointing directly at the tcase flange)
Custom one piece drive-shaft by Jesse at High Angle w/CV joint (65" long!)

Front:
4" AllPro SAS in the front
Saggy/crappy springs (Alcans some day :-)
Front shackles are 5" eye-to-eye

If you haven't done so already, re-tighten both your tcase flange nut as well as the pinion nut.  I had a ton of vibration before I rotated my rear axle and it worked everything loose.

Hope that helps bro....

[heep70 [OP]]

Thanks,  I have just about the same setup as you except my drive line is only 43" long.  Jesse also built my CV driveline.  The pinion points right at the tcase flange and all nuts and bolts are tight.  I get a vibration weather on the gas, cruising or slowing down.  It just stays there.  I figure it is because of the CV and vs driveline lenth.  Its the type of vibration that kids get a kick out of while talking.  It make your voice vibrate.  Yea, real funny tell you get tired of it.  My daughter has pretty much wrote this rig of as a pile of shiat. 

Not sure what to do to fix it besides lengthen the frame.  NOT! 

[Saber]

I (and Jesse too) were concerned that my drive line length were pushing the limits of too long.  Being that I have an extended cab, it's a long stretch.  I only experienced vibration over 35-40mph and mostly when I let off the gas (drive to coast).  If you're getting it all the time, you may have deeper issues (which = $$$).  Possibly worn bearings, either in your tcase and or 3rd member.  I suppose it all depends on how long you've driven with the vibes.  I probably drove a little too long on my old one piece and probably wore out the u-joints.  Oh well, it's only money...