Drive line angle/vibrations promblems? - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 02-11-2002, 08:53 PM Thread Starter
 
Join Date: Dec 2001
Posts: 792
Thanks: 0
Thanked 0 Times in 0 Posts
 
Drive line angle/vibrations promblems?

Yes, this is the same promblem you have been hearing about for a few weeks, but I know you guys are the experts, so please help.

I bought an angle finder today at sears and measured my angles,the pinion is running at 6 degrees and the transfer case is at 18 degrees. This leaves 12 which I hear is not OK. These angles are with 1/4" transfer case drop and a 4 degree shim in the rear.

what should I do now? How can I get the two in line with out lowering the transfer case. I will if I hve to but would rather not.

Please look at the attachment, it is an illistration of the promblem.

thanks very much
tony

79 CJ 5, 258, dana 30, model 20, T18, dana 20, 2.5" rancho lift, 1" shackles
Attached Images
File Type: bmp 9-684468-drivelineangle.bmp (87.3 KB, 3 views)
tonyscj5 is offline  
Sponsored Links
Advertisement
 
post #2 of (permalink) Old 02-11-2002, 10:11 PM
 
Join Date: Jan 2001
Posts: 769
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Drive line angle/vibrations promblems?

I think you mean your drive shaft is at 18 degrees?
I donít think your transfer case could be anywhere near that angle.
12 degrees on a drive shaft is not that bad but 18 degrees is.
Please clarify.

Trailhed.com
Jeeplvr is offline  
post #3 of (permalink) Old 02-11-2002, 10:47 PM Thread Starter
 
Join Date: Dec 2001
Posts: 792
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Drive line angle/vibrations promblems?

please show me a diagram of how to measure the angles, if mine are incorect

79 CJ 5, 258, dana 30, model 20, T18, dana 20, 2.5" rancho lift, 1" shackles
tonyscj5 is offline  
Sponsored Links
Advertisement
 
post #4 of (permalink) Old 02-12-2002, 01:52 AM
cj7jeep
Guest
 
Posts: n/a
Re: Drive line angle/vibrations promblems?

Might call around and see if you can find some different shims, more than 6 degrees. Probably the best thing would be a cv style rear driveshaft. Give Jesse at http://commerce.prodigybiz.com/custo...e/contact.html a call, he can give you info.

post #5 of (permalink) Old 02-12-2002, 04:37 AM
 
Join Date: Mar 2000
Posts: 611
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Drive line angle/vibrations promblems?

Take your new angle gauge and set it either on top of your shaft or up underneath your shaft. The reading on the gauge is your driveshaft angle. Now remove the shaft itself. Rock the vehicle a little bit until the mounting faces of the two yokes (pinion and transfer case output) are both vertical. Now set the gauge on the face of your rear differential pinion yoke. This will tell you how many degrees up from horizontal the pinion is pointing. Now set the guage on the face of the Tcase output yoke. This will tell you how many degrees down from horizontal your Tcase is sitting. When everything is working and in balance, these two angles need to be the same for there to be no vibration.

In a static situation, with the vehicle not moving, the rear differential pinion should be one or two degrees less than the transfer case output angle. This is because as you start moving and applying torque to the driveline and consequently the springs, the rear differential will "wrap" or strain upwards against the torque a little bit, thus increasing it's "up" angle (as measured from a horizontal line). When the wrap is happening i.e. you are driving down the road, that is when you want the angles to be the same, as opposed to when you are not moving and the driveline is not under any pressure.

So, what is your driveshaft angle? 18 degrees may be at the upper limit for a conventional shaft; I can't remember, and I think someone (Wayne?) posted the number in one of your earlier inquiries on this problem. But first try measuring and correcting the pinion and Tcase output angles.

And I didn't read all your earlier posts; are you sure it is a driveline problem? An out-of-balance wheel can cause vibration, sometimes felt only at certain speeds. How about the driveshaft itself, could you have knocked a weight off, or dented it minutely, throwing it out of balance? Did the vibe start all of a sudden, or has it been present since you've had the vehicle? More than once I have gotten all caught up in a complex problem only to find that it was something simple that I overlooked.

Max

82 CJ, some stuff stock, some stuff not
Have you hugged your Jeep today?
http://www.alpine14rs.org
CJ money pit is offline  
post #6 of (permalink) Old 02-12-2002, 08:26 AM
Official Historian
 
WILL's Avatar
 
Join Date: Sep 1999
Location: Hot Springs, AR
Posts: 8,339
Thanks: 1
Thanked 5 Times in 5 Posts
 
Re: Drive line angle/vibrations promblems?

Try turning you shim around so the thick part is to the front. That should get your angles more in line.

WILL is offline  
post #7 of (permalink) Old 02-12-2002, 10:25 AM
 
Join Date: Jan 2001
Posts: 769
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Drive line angle/vibrations promblems?

By the illustration the shim is in correctly. The limit for a conventional drive shaft is 15 degrees. If you are exceeding 15 degrees then a CV shaft is a way to eliminate most of the vibration. They are expensive and you will have to reposition the spring perches on your axle tubes so that the pinion will point at the transfer case output shaft less 2 degrees.
Here is a link to some very good reading material on this subject.
<a href=http://www.4xshaft.com/selection.html>Drive shaft angle info</a>


Trailhed.com
Jeeplvr is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome