Need some help explaining pinion angles, YSE, CV joints, upper control arms....etc. - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > TJ Jeep Wrangler Forum > TJ Tech Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 06-30-2010, 08:33 PM   #1
Jeeper
 
Join Date: Jun 2010
Posts: 174
Need some help explaining pinion angles, YSE, CV joints, upper control arms....etc.

Ok - I have looked at these two write ups:

Tom Wood's Custom Drive Shafts - Driveline 101

Pinion Angle Alignment - 1

However I still don't know what all this stuff does!

Say my pinion angle is slightly off, like in this picture attached from under my jeep, what is the best way to remedy this? I have adjustable lower control arms, but I don't see how adjusting those will make the angle any better.

So what are my options?

A YSE to flatten the angle?

Installing adjustable upper arms and then dial the angle in?

Install a double cardan driveshaft?

I am unclear on what to do here...

Thanks,
Attached Thumbnails
Click image for larger version

Name:	_Media Card_BlackBerry_pictures_IMG00143-1.jpg
Views:	52
Size:	164.1 KB
ID:	21127  

CubbieBlue is offline   Quote Quick Reply
Old 06-30-2010, 08:42 PM   #2
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 33,231
Images: 2
For the OE style of conventional (non-CV) driveshaft you have, the rear pinion angle needs to be at the same angle that the transfer case output shaft is at. The two shafts need to be exactly parallel to each other.

If your rear pinion shaft angle is too high, as it appears it may be, lengthening your rear lower control arms will roll the bottom of the rear axle back towards the rear which will lower the axle's pinion shaft angle. The pinion shaft angle can be anywhere from exactly the same as the t-case output shaft angle to as low as 1 to 3 degrees under that of the t-case output shaft angle. The pinion angle absolutely cannot above the t-case output shaft's angle however.

Tom Wood's drawing, below, shows what I mean where the two shafts need to be parallel.

Make sense?
Attached Thumbnails
Click image for larger version

Name:	2joint_angle.jpg
Views:	53
Size:	33.2 KB
ID:	21128  

__________________
When you have a choice, buy American.

Jerry Bransford is offline   Quote Quick Reply
Old 06-30-2010, 08:48 PM   #3
Jeeper
 
Join Date: Aug 2007
Location: So Cal.
Posts: 1,146
Remember if you don't have a cv drive shaft joint on the top end of your drive shaft then both the transfer case output shaft and the pinion shaft must remain at the same angle in relationship to each other. If you have a cv joint drive shaft then you can adjust the rear end so that the pinion will be pointing at the transfer case output shaft. If this is clear like mud then check out this website and it will be explained much better than I can.

Driveline 101

Man I type too slow, You beat me too it Jerry but the link here is the one from your pic.

Donn
__________________
My Jeep is NOT an suv and Your suv is NOT a Jeep
30-284 is offline   Quote Quick Reply
Old 06-30-2010, 09:54 PM   #4
Jeeper
 
Join Date: Jun 2010
Posts: 174
Quote:
Originally Posted by Jerry Bransford View Post
For the OE style of conventional (non-CV) driveshaft you have, the rear pinion angle needs to be at the same angle that the transfer case output shaft is at. The two shafts need to be exactly parallel to each other.

If your rear pinion shaft angle is too high, as it appears it may be, lengthening your rear lower control arms will roll the bottom of the rear axle back towards the rear which will lower the axle's pinion shaft angle. The pinion shaft angle can be anywhere from exactly the same as the t-case output shaft angle to as low as 1 to 3 degrees under that of the t-case output shaft angle. The pinion angle absolutely cannot above the t-case output shaft's angle however.

Tom Wood's drawing, below, shows what I mean where the two shafts need to be parallel.

Make sense?
See it appears to me that the rear shaft is lower than the t-case shaft. How would I determine that accurately and if that is the case how do I adjust that?

Do you think it is possible that my driveshaft itself may be the issue? I can snap another few pics if it would help...

Edit: It may be possible I am confusing the term "lower" as we are talking about angles...are you saying the angle is lower, or the actual shaft is towards the ground lower.
CubbieBlue is offline   Quote Quick Reply
Old 06-30-2010, 10:06 PM   #5
Drives by Braille

WF Supporting Member
 
AzTJ's Avatar
 
Join Date: Dec 2006
Location: For-8-Oh!
Posts: 13,629
If you have adjustable lower control arms like stated, lengthen them out so that the pinion on the axle will drop. Without a CV shaft the outputs need to be parallel. If you had a CV shaft, your axles pinion output would need to be pointed up at an angle to aim at the output of the t-case.
AzTJ is offline   Quote Quick Reply
Old 06-30-2010, 10:33 PM   #6
Jeeper
 
Join Date: Jun 2010
Posts: 174
Quote:
Originally Posted by AzTJ View Post
If you have adjustable lower control arms like stated, lengthen them out so that the pinion on the axle will drop. Without a CV shaft the outputs need to be parallel. If you had a CV shaft, your axles pinion output would need to be pointed up at an angle to aim at the output of the t-case.
Like I said, it appears to me if I lengthen them the rear end will drop, and be out of angle even further. I think that I actually have to RAISE the diff. side.

again, how do I tell exactly and what would I need to do to raise the diff side - get adjustable upper arms?
CubbieBlue is offline   Quote Quick Reply
Old 06-30-2010, 10:39 PM   #7
Drives by Braille

WF Supporting Member
 
AzTJ's Avatar
 
Join Date: Dec 2006
Location: For-8-Oh!
Posts: 13,629
You need to LOWER the diff, not raise it do to the fact that you do not have a CV shaft.

But if your driveshaft is going to fall out, I wouldn't bother, and just get an SYE and CV shaft. It'll save a ton of headache.
AzTJ is offline   Quote Quick Reply
Old 06-30-2010, 10:46 PM   #8
Jeeper
 
Join Date: Jun 2010
Posts: 174
Quote:
Originally Posted by AzTJ View Post
You need to LOWER the diff, not raise it do to the fact that you do not have a CV shaft.

But if your driveshaft is going to fall out, I wouldn't bother, and just get an SYE and CV shaft. It'll save a ton of headache.
Huh? I THINK my ds is fine. Why do I need to lower the diff if (as it appears to me) I need to raise it to make the angles consistent?
CubbieBlue is offline   Quote Quick Reply
Old 06-30-2010, 10:57 PM   #9
Drives by Braille

WF Supporting Member
 
AzTJ's Avatar
 
Join Date: Dec 2006
Location: For-8-Oh!
Posts: 13,629
Is your diffs output parallel to the output of the t-case? If not, it needs to be. That's the issue at hand.

Refer to Jerry's image above.
AzTJ is offline   Quote Quick Reply
Old 06-30-2010, 11:05 PM   #10
Jeeper
 
Join Date: Jun 2010
Posts: 174
Ok I drew some lines in on this one

I think maybe the semantics here are getting me confused.

So what do I need to do to match these up?

Also if someone thinks my photoshop is crap, feel free to redraw better lines.
Attached Thumbnails
Click image for larger version

Name:	pangleedit.jpg
Views:	42
Size:	165.0 KB
ID:	21141  
CubbieBlue is offline   Quote Quick Reply
Old 06-30-2010, 11:15 PM   #11
Drives by Braille

WF Supporting Member
 
AzTJ's Avatar
 
Join Date: Dec 2006
Location: For-8-Oh!
Posts: 13,629
It would probably help to have a clearer picture from further back and more level. But what you highlighted are just the u-joints, not the outputs.

AzTJ is offline   Quote Quick Reply
Old 06-30-2010, 11:25 PM   #12
Jeeper
 
Join Date: Jun 2010
Posts: 174
Quote:
Originally Posted by AzTJ View Post
It would probably help to have a clearer picture from further back and more level. But what you highlighted are just the u-joints, not the outputs.

Ah hah! Ok, this works.

So, now back to my original question - what and how, do I go about adjusting that angle - and it is "low" correct?
CubbieBlue is offline   Quote Quick Reply
Old 06-30-2010, 11:33 PM   #13
Drives by Braille

WF Supporting Member
 
AzTJ's Avatar
 
Join Date: Dec 2006
Location: For-8-Oh!
Posts: 13,629
The image provided is too close to the drive shaft, one from a bit farther away that shows the t-case would help diagnose it better.
AzTJ is offline   Quote Quick Reply
Old 06-30-2010, 11:35 PM   #14
Jeeper
 
Join Date: Jun 2010
Posts: 174
Quote:
Originally Posted by AzTJ View Post
The image provided is too close to the drive shaft, one from a bit farther away that shows the t-case would help diagnose it better.
Ok, I'll snap a few tomorrow morning. I don't wanna be creepin' out the neighbors takin pictures of stuff underneath my Jeep in the dark...

Also thank you and I apologize for my newbness.
CubbieBlue is offline   Quote Quick Reply
Old 06-30-2010, 11:46 PM   #15
Drives by Braille

WF Supporting Member
 
AzTJ's Avatar
 
Join Date: Dec 2006
Location: For-8-Oh!
Posts: 13,629
No problem.
AzTJ is offline   Quote Quick Reply
Old 07-01-2010, 12:54 AM   #16
Jeeper
 
Join Date: Jun 2010
Posts: 174
OK I am wondering if the control arms installed on the rear of my TJ are actually FRONT lower control arms put in the wrong spot...these have a bend in them that only the front ones I have seen online have...hold on will get pics soon...

Hmmm..
CubbieBlue is offline   Quote Quick Reply
Old 07-01-2010, 12:59 AM   #17
Jeeper
 
Join Date: Jun 2010
Posts: 174
Eh nevermind they are shaped like these, which I guess can be used as either front or rear.

Front or Rear Lower Control Arms by 4Wheel Drive Hardware and Other Jeep Parts and Jeep Accessories by 4 Wheel Drive Hardware-RH1
CubbieBlue is offline   Quote Quick Reply
Old 07-01-2010, 01:08 AM   #18
Drives by Braille

WF Supporting Member
 
AzTJ's Avatar
 
Join Date: Dec 2006
Location: For-8-Oh!
Posts: 13,629
Yes, TJ lower arms are the same front and rear.
AzTJ is offline   Quote Quick Reply
Old 07-01-2010, 10:52 AM   #19
Jeeper
 
Join Date: Jun 2010
Posts: 174
New pics

It was really bright this morning so they are abit hard to see. Maybe click on them and get them enlarged to get a better version. I outlined the angles. On the second pic I outlined my control arms, which are kind of U shaped, so I don't think adjusting them will get the angle I need.

Also side question: The bolt in the middle of those control arms is NOT tight. I can loosen it with my hands. How imperative is to get those bolts really-freakin-tight? I tightened them as much as I could with my hand and drove to work and checked and they were still the same tightness, so driving isn't affecting them...

Thanks
Attached Thumbnails
Click image for larger version

Name:	markedwcontrol.jpg
Views:	51
Size:	190.4 KB
ID:	21148   Click image for larger version

Name:	marked-up-1.jpg
Views:	49
Size:	198.0 KB
ID:	21149  

CubbieBlue is offline   Quote Quick Reply
Old 07-01-2010, 10:53 AM   #20
Jeeper
 
Join Date: Jun 2010
Posts: 174
You can actually see the arms and the bolt I am talking about BETTER in the picture I didn't highlight it haha
CubbieBlue is offline   Quote Quick Reply
Old 07-01-2010, 11:52 AM   #21
Jeeper
 
Join Date: Jun 2010
Posts: 174
Quote:
Originally Posted by CubbieBlue View Post
It was really bright this morning so they are abit hard to see. Maybe click on them and get them enlarged to get a better version. I outlined the angles. On the second pic I outlined my control arms, which are kind of U shaped, so I don't think adjusting them will get the angle I need.

Also side question: The bolt in the middle of those control arms is NOT tight. I can loosen it with my hands. How imperative is to get those bolts really-freakin-tight? I tightened them as much as I could with my hand and drove to work and checked and they were still the same tightness, so driving isn't affecting them...

Thanks
From these it actually does look like the angle is too high. If that is the case I could just lengthen those control arms a bit...thoughts? And what I need to undo to do that?
CubbieBlue is offline   Quote Quick Reply
Old 07-01-2010, 11:58 AM   #22
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 33,231
Images: 2
Quote:
Originally Posted by CubbieBlue View Post
From these it actually does look like the angle is too high. If that is the case I could just lengthen those control arms a bit...thoughts? And what I need to undo to do that?
That's what I was saying in post #2 above. To lenghten the lower control arms, you just undo one end, unscrew both arms one turn, and reinstall it and test to see if your pinion angle is then ok. Just unscrew both arms an equal number of turns until the two angles are parallel as they should be. Better to have the pinion angle 1-2 degrees too low than too high.
__________________
When you have a choice, buy American.

Jerry Bransford is offline   Quote Quick Reply
Old 07-01-2010, 12:06 PM   #23
Jeeper
 
Join Date: Jun 2010
Posts: 174
Quote:
Originally Posted by Jerry Bransford View Post
That's what I was saying in post #2 above. To lenghten the lower control arms, you just undo one end, unscrew both arms one turn, and reinstall it and test to see if your pinion angle is then ok. Just unscrew both arms an equal number of turns until the two angles are parallel as they should be. Better to have the pinion angle 1-2 degrees too low than too high.
I am assuming undoing the top would be easier than the wheel end?

Also I would need to jack the jeep up for this correct?

Also what do you think about those loose control arm bolts?

(I should pay you for consulting!)
CubbieBlue is offline   Quote Quick Reply
Old 07-01-2010, 12:15 PM   #24
Jeeper
 
Join Date: Jun 2010
Posts: 174
Here, this pic is much better. I just thought though - what happens if I lengthen those control arms and the DS is not long enough?
Attached Thumbnails
Click image for larger version

Name:	better.jpg
Views:	50
Size:	201.1 KB
ID:	21150  
CubbieBlue is offline   Quote Quick Reply
Old 07-01-2010, 11:01 PM   #25
Jeeper
 
Join Date: Jun 2010
Posts: 174
Quote:
Originally Posted by CubbieBlue View Post
Here, this pic is much better. I just thought though - what happens if I lengthen those control arms and the DS is not long enough?
i've been browsing some other threads on this issue (it seems not many have updated with a solution!) that sometimes tightening the output shaft nut does the trick. Can someone point me to the location of this nut?
CubbieBlue is offline   Quote Quick Reply
Old 07-02-2010, 11:30 AM   #26
Jeeper
 
Join Date: Jun 2010
Posts: 174
Also I am going to go ahead and remove the rear driveshaft tomorrow. Can I just pop it off and drive around in 4H safely for awhile?
CubbieBlue is offline   Quote Quick Reply
Old 07-02-2010, 11:36 AM   #27
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 33,231
Images: 2
Quote:
Originally Posted by CubbieBlue View Post
Can I just pop it off and drive around in 4H safely for awhile?
Yep, no problem.
__________________
When you have a choice, buy American.

Jerry Bransford is offline   Quote Quick Reply
Old 07-02-2010, 12:52 PM   #28
Jeeper
 
Join Date: Jun 2010
Posts: 174
Thanks Jerry!
CubbieBlue is offline   Quote Quick Reply
Old 07-02-2010, 03:01 PM   #29
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 33,231
Images: 2
Quote:
Originally Posted by CubbieBlue View Post
i've been browsing some other threads on this issue (it seems not many have updated with a solution!) that sometimes tightening the output shaft nut does the trick. Can someone point me to the location of this nut?
There is no output shaft nut, the t-case output shaft is a splined shaft that the front of the rear driveshaft slips onto. You only get a rear output shaft nut after installing a SYE kit.
__________________
When you have a choice, buy American.

Jerry Bransford is offline   Quote Quick Reply
Old 07-03-2010, 05:48 PM   #30
Jeeper
 
Join Date: Jun 2010
Posts: 174
Alright today I swapped out my spark plugs (that was a breeze) and disconnected the rear driveshaft and took it for a spin. I had a little bit of trouble getting it to engage in 4wd (had to put it in 4L first then put it up to 4H for some reason, but eventually got her going) and took her for a spin.

Those front tires like to squeal!

The U joints in the rear driveshaft are perfect. No vibration on take off with it removed. HOWEVER on driving at 50-60 mph 98% of the rhythmic pulsing is gone, but still a little bit remains! It is very slight, and I am stumped. I am wondering if perhaps the front driveshaft might be vibing extremely slightly as well? I guess I will adjust lower the pinion angle one or two turns, take it for a spin and if it persists remove the front DS and see what happens.

Anybody got any other ideas?

Jeep actually rides real nice in front wheel drive haha.

CubbieBlue is offline   Quote Quick Reply
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum 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:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may 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 Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
control arms mrbigjeep TJ General Discussion Forum 8 08-23-2010 11:19 AM
Exact Measurement lenght for RE adj. upper control arms? EdJonesJeeper TJ Tech Forum 9 05-20-2010 11:09 PM
Changing out stock upper control arms thelightguy TJ Tech Forum 0 02-25-2010 04:08 PM
Upper Control Arms - SYE - Drive shaft CMLitzenberg TJ Tech Forum 10 04-11-2009 10:52 AM
Upper control arms 03rubi Classifieds Archive 0 11-28-2008 10:26 AM



Download our Mobile App

» Network Links
»Jeep Parts
» Featured Product

All times are GMT -5. The time now is 12:22 AM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC