Modified XJ Cherokee Tech XJ (84-01)
All modified tech questions. If it modifies your XJ beyond stock parts ask it here.
Sponsored by:
Sponsored by:

8.25 gear pattern opinion request

Thread Tools
 
Search this Thread
 
Old 07-24-2015, 02:13 PM
  #1  
Newbie
Thread Starter
 
MECRAM's Avatar
 
Join Date: Mar 2011
Location: AZ
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Year: 95
Model: Cherokee
Engine: 4.0L
Default 8.25 gear pattern opinion request

I am planning on replacing my gears soon - I had a "professional" install the gears only to replace them due them singing obnoxiously loud. I have never set gears up before and this is the pattern I came up with. With research of patterns and set up techniques I achieved a different mph range whine 35-55 and no coast whine. Going to start again and was looking for some direction. I feel I still need more pinion shim though from a forum chart it appears I may need less... Backlash from memory of nearly two years ago was 008-010.

Thanks for your help.
Attached Thumbnails 8.25 gear pattern opinion request-c360_2013-01-26-21-13-35.jpg  
Old 07-24-2015, 05:22 PM
  #2  
Banned
 
Jeep Driver's Avatar
 
Join Date: Jan 2014
Posts: 1,054
Likes: 0
Received 2 Likes on 1 Post
Model: Cherokee
Default

If it 'sings' it's typically a pinion bearing issue.

If it 'howls' it's likely the R&P.
Old 07-24-2015, 05:30 PM
  #3  
Newbie
Thread Starter
 
MECRAM's Avatar
 
Join Date: Mar 2011
Location: AZ
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Year: 95
Model: Cherokee
Engine: 4.0L
Default

Your correct, I should have clarified that it was from the R&P and not a bearing noise. It's very loud about 1/2 to 3/4 of a factory radio volume. I had to open up the diff due to a bearing noise from the carrier bearing failing, I suspect from excess preload from the shop that installed them 3x's in an attempt to address a whine. First time, whine was always, second was fwy speeds third at 35-55.

Last edited by MECRAM; 07-24-2015 at 05:38 PM. Reason: add details
Old 07-24-2015, 05:45 PM
  #4  
CF Veteran
 
SeriousOffroad's Avatar
 
Join Date: Apr 2008
Posts: 13,952
Likes: 0
Received 15 Likes on 13 Posts
Model: Cherokee
Default

What brand gears?
Old 07-24-2015, 05:46 PM
  #5  
Banned
 
Jeep Driver's Avatar
 
Join Date: Jan 2014
Posts: 1,054
Likes: 0
Received 2 Likes on 1 Post
Model: Cherokee
Default

I won't pretend to be an expert here......but......

If your backlash is correct.......the pattern looks good.
Old 07-24-2015, 06:27 PM
  #6  
Newbie
Thread Starter
 
MECRAM's Avatar
 
Join Date: Mar 2011
Location: AZ
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Year: 95
Model: Cherokee
Engine: 4.0L
Default

That's what I thought as well before I buttoned it up. Unfortunately it still howls - Thanks for the input.
Old 07-26-2015, 04:58 PM
  #7  
Newbie
Thread Starter
 
MECRAM's Avatar
 
Join Date: Mar 2011
Location: AZ
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Year: 95
Model: Cherokee
Engine: 4.0L
Default

They're Motive Gears
Old 07-26-2015, 11:51 PM
  #8  
Member
 
InitialForce's Avatar
 
Join Date: Jul 2015
Location: Bakersfield, CA
Posts: 100
Likes: 0
Received 1 Like on 1 Post
Year: 2001
Model: Cherokee
Engine: 4.0
Default

If you pattern, backlash and pinion bearing preload are good really only thing is left is maybe the carrier bearing shims? Possible deflection issue under load? (I am assuming that pattern is freewheeled manually under no load)
Old 07-27-2015, 06:18 AM
  #9  
CF Veteran
 
SeriousOffroad's Avatar
 
Join Date: Apr 2008
Posts: 13,952
Likes: 0
Received 15 Likes on 13 Posts
Model: Cherokee
Default

No shims on an 8.25" carrier.

Pinion deflection is not an issue at normal speeds, only under high torque.
Old 07-27-2015, 11:00 AM
  #10  
Senior Member
 
Alpha 1-4's Avatar
 
Join Date: Mar 2013
Posts: 655
Received 1 Like on 1 Post
Model: Cherokee
Default

Looks like the pattern might be too high on the tooth. What shim did you use behind the pinion?
Old 07-27-2015, 01:02 PM
  #11  
Seasoned Member
 
ZJMAX's Avatar
 
Join Date: May 2014
Location: Nor Cal
Posts: 371
Likes: 0
Received 2 Likes on 2 Posts
Year: 1993 & 1994
Model: Grand Cherokee
Engine: 4.0
Default

Did you follow the break in for the new gears?

Max
Old 07-27-2015, 04:37 PM
  #12  
Member
 
InitialForce's Avatar
 
Join Date: Jul 2015
Location: Bakersfield, CA
Posts: 100
Likes: 0
Received 1 Like on 1 Post
Year: 2001
Model: Cherokee
Engine: 4.0
Default

This might be a stupid question (reading a book on how to regear in prep for my own axles) did you double check your ring and pinion for matching serial numbers? My book warns about making sure the numbers match if there are any because i guess the ring and pinion are lapped at the factory to each other and you can't mix and match ring and pinions according to this book.
Old 07-28-2015, 11:01 AM
  #13  
Member
 
autosurgeon's Avatar
 
Join Date: Mar 2014
Location: Lawrence, MI
Posts: 228
Likes: 0
Received 1 Like on 1 Post
Year: 2000
Model: Cherokee
Engine: 4.0 HO
Default 8.25 gear pattern opinion request

Your pattern is good. Either you have a FUBAR bearing. Or you didn't break in the gears.. Or remotely you got a mismatched ring and pinion. They will make noise until they settle in. I always do 250 miles open her up clean out the pig look for any funny wear or metal and fill and go another 500 and do it again. If everything looks good at the 750 mark install whatever expensive gear oil you like and drive it.
Old 07-28-2015, 12:40 PM
  #14  
Newbie
Thread Starter
 
MECRAM's Avatar
 
Join Date: Mar 2011
Location: AZ
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Year: 95
Model: Cherokee
Engine: 4.0L
Default

Originally Posted by Alpha 1-4
Looks like the pattern might be too high on the tooth. What shim did you use behind the pinion?
That's what I believe as well.
It's been a while now, from memory I believe about 25 +/- or 17 really cannot remember

Last edited by MECRAM; 08-07-2015 at 02:19 PM. Reason: Add
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Longboard_757
Cherokee Chat
13
12-10-2015 08:04 AM
Azzy
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
0
09-08-2015 10:49 PM
SouthSeaPirate
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
17
09-07-2015 06:47 PM
ROCKRIDGE 4WD
Vendor Showcase
0
09-03-2015 05:29 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 


Quick Reply: 8.25 gear pattern opinion request



All times are GMT -5. The time now is 03:07 AM.