Driveline vibration (pinion angle) help. - JeepForum.com
 5Likes
Reply
 
LinkBack Thread Tools
post #1 of 40 Old 02-11-2018, 11:43 AM Thread Starter
MrButterfield
Registered User
 
MrButterfield's Avatar
1976 CJ5 
 
Join Date: Jun 2017
Location: Portland
Posts: 105
Garage
Question Driveline vibration (pinion angle) help.

The meat of my question for those punchline kinda folks: What does a poor pinion angle vibration feel like?

Best I can tell, my operating angle is 6.1 degrees for my rear drive shaft. I have a terrible vibration that is speed and torque related, only under acceleration or deceleration. When I push the clutch in, its completely gone at any and all speeds. At a crawl going up the hill, my shifter does an orbital/oval motion. At 30mph, I feel a low frequency vibration starting that feels under my seat. At 45mph to 60mph, it buzzes like it wants all the screws loose. Its very intense and even distorts the reflection in the rear view mirror. It feels like I'm riding in a giant variable speed sander. At about 65-70, I think my poor 258 is trying so hard that it wouldn't know if a wheel fell off so the vibration disappears. I pulled the rear drive shaft and drove down using the front axle and the vibration was gone at all speeds.

Is this too much of an operating angle? What does a poor pinion angle vibration feel like? I'm excellent with engines and electrical but not so good from the transmission on.

A little back story, bought the Jeep a couple years ago. It had 16" heavy wheels with load range E tires on it. It vibrated somewhat back then, but nothing like now. I removed a bunch of excess weight from it, including a 150lb diamond plate in the cargo area and a terribly welded addition to the roll bar that ran into the front. The more weight I removed, the worse the vibration got. I put new wheels and tires on it, replaced the transmission mounts, etc. The more I fixed it up and drove it, the worse the vibration got. I do have a shudder in the clutch, but if the clutch was the culprit, I would think the vibration would be RPM related. I was told by a reputable suspension guy that my jeep has a 2" suspension lift.

I've read through almost all of the threads on this and the first thing people say is "It's your u-joints" or "Check your wheel balance". It isn't and I did on all the obvious accounts.

So here's a list of what I think ISN'T causing the vibration;

-wheel balance: Wheels and tires are brand new and have been balanced by a shop I know and trust. (vibration was present with old wheels and tires)
-U-joints: I replaced the rears with brand new Spicer brand heavy duty U-joints
-Transmission or transfer case: No excessive play on output. Removed driveshaft and observed rotation of output and didn't see a wobble. Vibration gone on test drive with rear driveshaft out.
-The drive shaft has very minimal side to side play and still has its balance weight attached.
-transmission mount and torque mount are brand new
-bent axle shafts or axle bearings: Replaced both side bearings/oil seals, inspected axle shafts.

I feel I'm answering my own question here but on the matter of drive train, I trust some of you guys way more than I trust myself.

Thanks guys!
Jeremy

MrButterfield is online now  
Sponsored Links
Advertisement
 
post #2 of 40 Old 02-11-2018, 12:17 PM
Fourtrail
Registered User
1974 CJ6 
 
Join Date: Dec 2007
Location: Illinois
Posts: 4,549
You need to measure the angle of the face of the pinion yoke and the transfercase yoke. they should be the same. also need to see if the springs are twisting up/down during accel/decel throwing off the angles.

80 CJ-5, 74 CJ-6, 56 CJ-5
Fourtrail is offline  
post #3 of 40 Old 02-11-2018, 01:52 PM
RenoF250
Registered User
1985 CJ7 
 
Join Date: Sep 2011
Location: Reno
Posts: 2,712
Do you have a pic? Single cardan at each end? As said transfer case output and pinion shaft should be parallel, not pointed at each other. You want equal deflection from both u-joints. U-joints change speed when bent, both need to be at the same angle to cancel that out. If one is straight and the other bent, you will get what you are talking about.

NormWild likes this.

1985 CJ7 with 1994 4.6, Dana 44 4.10 TrueTracs
2001 TJ 4.0 Dana 44 4.10 TrueTracs
RenoF250 is offline  
 
post #4 of 40 Old 02-11-2018, 03:21 PM Thread Starter
MrButterfield
Registered User
 
MrButterfield's Avatar
1976 CJ5 
 
Join Date: Jun 2017
Location: Portland
Posts: 105
Garage
Quote:
Originally Posted by Fourtrail View Post
You need to measure the angle of the face of the pinion yoke and the transfercase yoke. they should be the same. also need to see if the springs are twisting up/down during accel/decel throwing off the angles.
Hey Fourtrail

I measured the T-Case yoke at 6.1 degrees and the pinion yoke at 11.9 degrees. Ill grab my neighbor when he comes home to check for axle wrap, although if there is, I doubt its much. The springs are so stiff it rides like an old washing machine.
MrButterfield is online now  
post #5 of 40 Old 02-11-2018, 03:27 PM Thread Starter
MrButterfield
Registered User
 
MrButterfield's Avatar
1976 CJ5 
 
Join Date: Jun 2017
Location: Portland
Posts: 105
Garage
Quote:
Originally Posted by RenoF250 View Post
Do you have a pic? Single cardan at each end? As said transfer case output and pinion shaft should be parallel, not pointed at each other. You want equal deflection from both u-joints. U-joints change speed when bent, both need to be at the same angle to cancel that out. If one is straight and the other bent, you will get what you are talking about.

https://www.youtube.com/watch?v=gmV4qwLfOMY
Thanks for the vid link. Ive watched that over and over again. My pinion angle is off and I'll correct that today, Jeepgod willing. Heres a pic. Laying underneath, its a little difficult to see how off the angle is. Once I crammed my phone up there and snapped a few pics, the misalignment is plain as day on the photos.

So clearly about a 6 degree misalignment. Obviously this needs to be fixed but is this the source of my vibration woes? Can these silly 6 degrees turn my Jeep into a 4 wheel drive paint shaker? Also, what is the most cost effective way to rectify this? Shims?

Thanks a bunch!
Jeremy
Attached Thumbnails
driveshaft 2.jpg  

Last edited by MrButterfield; 02-11-2018 at 03:38 PM.
MrButterfield is online now  
post #6 of 40 Old 02-11-2018, 03:40 PM Thread Starter
MrButterfield
Registered User
 
MrButterfield's Avatar
1976 CJ5 
 
Join Date: Jun 2017
Location: Portland
Posts: 105
Garage
Ive tried several pics and 1000 ways to sunday to get the pic to post right side up. Sorry if anyone spills their beer standing on their head.
MrButterfield is online now  
post #7 of 40 Old 02-12-2018, 02:18 AM
BagusJeep
Web Wheeler
 
BagusJeep's Avatar
1981 CJ7 
 
Join Date: Jul 2009
Location: Bali
Posts: 7,502
Is that axle pinion pointing UP?

If so, you have shown the issue. That is not stock.

Do the "perches" the leaf springs attach to look like they have been rewelded or is there a big wedge under there? It is possibel the diff housing has twisted but that would be unusual.

With that big difference your drivetrain is changing its rotational velocity substantially twice in each rotation, it will feel like a strong vibration. Your choices are putting the axle back in correctly or buying a double cardan drive shaft from Tom Woods which will cure it.

BagusJeep lives in Bali.

1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
BagusJeep is offline  
post #8 of 40 Old 02-12-2018, 02:23 AM
BagusJeep
Web Wheeler
 
BagusJeep's Avatar
1981 CJ7 
 
Join Date: Jul 2009
Location: Bali
Posts: 7,502
The reason you have two joints is that they move equally but opposite to each other, eliminating that change in rotational velocity.

You now only have one doing any movement, the other is still. therefore is one unbalanced joint.

as you can see that change in angle results in a change in rotational velocity at your pinion. The 7 degree difference may not seem like much in the graph but it is what you are feeling, if it was 20 degrees you would be bunny jumping down the road
Attached Images
 

BagusJeep lives in Bali.

1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
BagusJeep is offline  
post #9 of 40 Old 02-12-2018, 11:33 AM Thread Starter
MrButterfield
Registered User
 
MrButterfield's Avatar
1976 CJ5 
 
Join Date: Jun 2017
Location: Portland
Posts: 105
Garage
Quote:
Is that axle pinion pointing UP?
The differential is pointing up. In another thread somewhere, I was trying to identify this axle as my jeep wasnt supposed to come with a Dana 44.


The graph you posted really made some sense to me. I think there's just enough slack in my drive train that when I hit certain speeds, the driveshaft is accelerating and decelerating against the slack. That would reproduce perfectly the buzzing sensation that I get at higher speeds. It would also explain the oval cyclical motion my shifter does crawling in low gear up a hill.

Has anyone had good experience with axle shims? This jeep will never see extreme trail use. Mostly a toad behind my rv, some daily driving, and the occasional moderate trail.
MrButterfield is online now  
post #10 of 40 Old 02-12-2018, 02:18 PM
stripperguy
Registered User
2005 LJ Wrangler 
 
Join Date: Mar 2010
Location: Schenectady
Posts: 759
If your pinion is tilted up, the PO must have made it so.
Given that, you will likely not be able to correct the angles using shims, there's too much difference. You likely need a double cardan shaft. Even with that, you need to be sure that the single, rear U-joint does not rotate out of plane by more than a degree or so.
For what it's worth, I have a very short DC rear driveshaft, operating at nearly 35 degrees, and it's as smooth as can be.

1977 CJ5 is a CJ build ever really done?
2002 TJ gone
2005 TJ also gone
2005 LJ insurance wreck
stripperguy is online now  
post #11 of 40 Old 02-12-2018, 03:01 PM
John Strenk
Moderator
 
John Strenk's Avatar
1976 CJ5 
 
Join Date: Feb 2005
Location: Shalersville Ohio
Posts: 20,342
Mine is at 28* and very smooth.

IF it was a Dana 20 I'd have you check the axle tubes to make sure they haven't rotated on you

Here's your picture...
Attached Thumbnails
Flipped.jpg  


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


I drive a Prius to save money and buy more Jeep Parts....
John Strenk is offline  
post #12 of 40 Old 02-12-2018, 03:02 PM
80cj
Web Wheeler
 
80cj's Avatar
1980 CJ5 
 
Join Date: May 2002
Location: Hawaii
Posts: 8,050
Quote:
Originally Posted by MrButterfield View Post
Thanks for the vid link. Ive watched that over and over again. My pinion angle is off and I'll correct that today, Jeepgod willing. Heres a pic. Laying underneath, its a little difficult to see how off the angle is. Once I crammed my phone up there and snapped a few pics, the misalignment is plain as day on the photos.

So clearly about a 6 degree misalignment. Obviously this needs to be fixed but is this the source of my vibration woes? Can these silly 6 degrees turn my Jeep into a 4 wheel drive paint shaker? Also, what is the most cost effective way to rectify this? Shims?

Thanks a bunch!
Jeremy
Silly 6 degrees? That's your problem right there. The operating angle at both ends of the shaft have to be within a degree of each other. from the factory the pinion angle is a degree lower than the transfer case output. This compensates for pinion rotation under load.
80cj is offline  
post #13 of 40 Old 02-12-2018, 03:04 PM Thread Starter
MrButterfield
Registered User
 
MrButterfield's Avatar
1976 CJ5 
 
Join Date: Jun 2017
Location: Portland
Posts: 105
Garage
Quote:
Originally Posted by stripperguy View Post
If your pinion is tilted up, the PO must have made it so.
Given that, you will likely not be able to correct the angles using shims, there's too much difference. You likely need a double cardan shaft. Even with that, you need to be sure that the single, rear U-joint does not rotate out of plane by more than a degree or so.
For what it's worth, I have a very short DC rear driveshaft, operating at nearly 35 degrees, and it's as smooth as can be.
I agree. If he did weld on the spring perches at this angle though, it would be the ONLY decent weld he ever did. This Jeep was supposed to come with an AMC 20 but its a Dana 44. Not only that, the BOM doesn't return on the dana lookup page.

And as for the shims, after re-measuring, there is a 5.8 degree difference on my pinion angle. The pinion needs to come down to align with the transfer case yoke. Why wouldn't a 6 degree steel shim sort the whole shebang out? From what I read here and a few other places, this would give me .2 degrees over which would help to account for any axle wrap I would incur under torque.
MrButterfield is online now  
post #14 of 40 Old 02-12-2018, 03:07 PM Thread Starter
MrButterfield
Registered User
 
MrButterfield's Avatar
1976 CJ5 
 
Join Date: Jun 2017
Location: Portland
Posts: 105
Garage
Quote:
Originally Posted by 80cj View Post
Silly 6 degrees? That's your problem right there. The operating angle at both ends of the shaft have to be within a degree of each other. from the factory the pinion angle is a degree lower than the transfer case output. This compensates for pinion rotation under load.
Completely agree, 80cj! I was being snarky about the 6 degrees. It was tough to see how misaligned it was while laying on my back looking up from the garage floor. Once I got a photo of it, BAM! Plain as day.
MrButterfield is online now  
post #15 of 40 Old 02-12-2018, 03:16 PM
80cj
Web Wheeler
 
80cj's Avatar
1980 CJ5 
 
Join Date: May 2002
Location: Hawaii
Posts: 8,050
Quote:
Originally Posted by MrButterfield View Post
Completely agree, 80cj! I was being snarky about the 6 degrees. It was tough to see how misaligned it was while laying on my back looking up from the garage floor. Once I got a photo of it, BAM! Plain as day.
Is the Jeep lifted? I see from your profile that it has a Dana 44 so the P.O. probably swapped it in and rewelded the spring perches without giving any thought to U-joint geometry.
80cj is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com 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 e-mail address for yourself.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



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 On
Refbacks are On

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